56 results
Search Results
2. Population genomics and demographic modeling enhance our understanding of trophic level interactions in biological control.
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Sethuraman, Arun and Obrycki, John J.
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FOOD chains , *POPULATION dynamics , *NUCLEOTIDE sequencing , *GENOMICS , *PROOF of concept - Abstract
• Population genomics can elucidate historical and contemporary population dynamics of natural enemies, their pests, conspecific competitors, and parasitoids. • Demographic models based on genomic data can enhance understanding of trophic level interactions across species. • In this paper we present a proof of concept using population genomic techniques to complement ecological studies of population dynamics across trophic levels. In this paper, we focus on the application of population genomics, including next-generation sequencing and demographic modeling, to enhance the understanding of historical and contemporary trophic level interactions that are a fundamental basis of biological control. We outline how the integration of ecological approaches with population genomics and demographic modeling can provide additional insights into existing trophic interactions and how natural enemies, their parasitoids, and pest species evolve through these interactions, potentially affecting future levels of biological control. We briefly review and summarize our recent population genomic studies of predatory ladybird beetles and discuss how our results provide guidelines for the use of population genomics techniques and population demographic modeling to enhance our understanding of trophic level interactions. Our intent is to demonstrate as a proof of concept, how these methods can supplement currently used techniques and add a complementary genomic aspect to ecological understandings of trophic level interactions, including estimates of effective population sizes of natural enemies and pest species, examination of correlations between these effective population sizes, and evolutionary changes in natural enemies and pest species which may influence levels of biological control. This in combination with experiments and simulations provide a well-rounded framework for using population genomics to inform multi-tier trophic level interactions. [ABSTRACT FROM AUTHOR]
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- 2024
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3. PROSPECTS FOR THE BIOLOGICAL CONTROL OF WEEDS IN ARGENTINA.
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Anderson, F.E., Zalba, S.M., Ansaldi, J., Sosa, A, Mc Kay, F., and Cabrera Walsh, G.J.
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BIOLOGICAL weed control , *AGRICULTURE , *INTRODUCED species , *PUBLIC support , *PHYSIOLOGICAL control systems , *INVASIVE plants - Abstract
• Classical weed biological control is hardly practiced in Argentina today. • There is a small community of local experts that work mostly for overseas projects. • The National Strategy on Invasive Alien Species promotes biocontrol initiatives. • A prioritization process is developed to select the best target(s) for biocontrol. • Public awareness and outreach activities could help gain biocontrol public support. Argentina hosted pioneering classical weed biological control projects that were carried out by state institutions between the 1970s and 1990s, at a time when the practice was almost unheard of in Latin America. Despite the early development of these initiatives, the discipline did not prosper and all projects were discontinued. Notwithstanding, Argentina continued to provide biological control agents for the control of weeds in many other parts of the world, ensuring the expertise persisted. Although public concern about invasive plants and chemical-dependent agricultural practices has increased over time, it did not lead to a greater acceptance of classical biological control of weeds, which is still regarded with mistrust or ignored in many public and academic circles alike. Furthermore, there are no systems in place to reach a consensus on declaring weeds as targets for biological control in Argentina. In this paper we discuss different ways in which the community of researchers working in the field in Argentina can help relaunch the biological control of weeds, including the preparation of a prioritized list of target species. A list of this kind would not only reduce costs, but also help in developing trust in the discipline of biological control informing regulators and decision makers in this regard. Prospects are brighter today than a few years ago, but considerable communication and educational work on the benefits of this practice is still required to gain more support before it can effectively be re-implemented. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Use of the generalist predator Anystis baccarum in greenhouse IPM: Interactions with other biological control agents, a laboratory study.
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Saito, Taro, Buitenhuis, Rosemarije, and Brownbridge, Michael
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PREDATORY mite , *BIOLOGICAL pest control agents , *GREENHOUSES , *FUNGAL spores , *MEDITERRANEAN flour moth , *PREDATORY animals , *BEAUVERIA bassiana - Abstract
[Display omitted] • Anystis baccarum attacked and fed on smaller phytoseiid predatory mites, but mortality was reduced when A. baccarum was provided with an alternate food source. • Orius insidiosus, Stratiolaelaps scimitus and Delphastus catalinae were rarely attacked by A. baccarum , presumably due to their similarity in size, or limited habitat overlap. • Anystis baccarum was not susceptible to Beauveria bassiana (GHA strain) when exposed to surface residues of conidia on filter paper. A generalist predatory mite, Anystis baccarum (L.), was developed as a new biocontrol agent in Canada, and became commercially available in 2022. Because successful biological control programs in greenhouse crops rely on the release of several natural enemies simultaneously to deal with multiple pest species, this study assessed the interaction of A. baccarum with other commonly used biocontrol agents in laboratory trials. Note that only adult stages were used, because the agents tested are predominantly sold and released as adults. Anystis baccarum killed and consumed the generalist phytoseiid mites, Neoseiulus cucumeris (Oudemans) and Amblyseius swirskii Athias-Henriot; however, the mortality of the phytoseiid mites was reduced when an alternative food, Ephestia kuehniella Zeller eggs, was available. There was no intra-guild interaction between A. baccarum and the soil-dwelling predatory mite, Stratiolaelaps scimitus (Womersley). No statistically significant mortality was observed when Orius insidiosus (Say), a generalist hemipteran, or Delphastus catalinae (Horn), a coccinelid beetle used to control whiteflies, were confined with A. baccarum without alternative food for 24 h. The susceptibility of A. baccarum to the entomopathogenic fungus Beauveria bassiana (Balsamo) GHA strain was evaluated by exposing the mites to conidia in a filter paper bioassay. Differences in mite mortality were not significant across all treatments, and only one case of successful sporulation fungal growth was observed from cadavers recovered in the experiments; similarly, differences in the number of eggs produced were not significant across all treatments. Although the laboratory trials sometimes showed severe predation pressure from A. baccarum on other biocontrol agents, they are likely to be functionally compatible in the greenhouse owing to differences in habitat preferences and availability of other prey (pests) or another food source. Results of the current study provide insights that will enable the development of rational biocontrol programs that include A. baccarum. [ABSTRACT FROM AUTHOR]
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- 2023
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5. Analysis of Trichoderma as an effective biological control agent against the honey fungus (Armillaria spp.).
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Poveda, Jorge, Millen, Morgan R., and Bailey, Andy M.
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TRICHODERMA , *ROOT rots , *HONEY , *MYCOSES , *PLANT colonization , *AGRICULTURE - Abstract
• Trichoderma spp. is a BCA widely studied and used in agriculture. • Armillaria spp. is a globally important pathogen of agricultural/forestry species. • So far, there are 30 studies on the effective control of ARR by Trichoderma. • Trichoderma effectively control Armillaria in different experimental conditions. • So far, there are four mechanisms of action identified in this biological control. • More research is needed on the use of Trichoderma against Armillaria. Trichoderma is a genus of filamentous fungi with several species widely studied and used as biological control agents (BCAs) in agriculture. With respect to fungal disease control, Trichoderma spp. can use different mechanisms of action, including mycoparasitism, antibiosis, competition and/or activation of plant defences. Armillaria spp. are the causal pathogens of Armillaria root rot (ARR) disease, which is widely distributed and of great economic and environmental importance in agriculture and forestry. ARR can be devastating to plant health, through colonisation and rotting of the root system and collar of the infected plant/tree, which can cause a reduction in yield and eventually death. Armillaria can live as a saprophyte that survives on dead plant material, making eradication of ARR extremely difficult. In an exhaustive analysis of work published to date on the control of Armillaria spp. by Trichoderma spp., using the WoS and Scopus databases, we identified 31 papers. We discuss these reports in light of their key findings, including number of publications per year, the countries where they were published, the journals and the citations obtained so far. Although the vast majority do not identify the mechanism of action involved in control, some describe mycoparasitism, antibiosis, competition or modification of the rhizospheric microbiota as being responsible for effective biological control of the pathogen. Further research into these mechanisms and additional in-depth analysis of less studied or currently unidentified mechanisms, such as the activation of plant defences, would be highly beneficial to our understanding of Trichoderma as a BCA of Armillaria. [ABSTRACT FROM AUTHOR]
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- 2024
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6. RETRACTED: Biocontrol of Fusarium wilt in tomato by Trichoderma spp.
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Liu, Qingchun, Zhang, Shouan, and De Cote, Jose Antonio
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FUSARIUM , *AUTHOR-editor relationships , *COLLEGE buildings , *TOMATOES , *FUSARIUM oxysporum , *APOLOGIZING , *TRICHODERMA - Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). This article has been retracted at the request of the authors. The strains T. atroviride T11 and T. asperellum T25 are property of the University of Salamanca. Post publication, the authors informed the editor that the material transfer agreement (MTA) between the project sponsor (iQBiotech LLC.) and the owner (University of Salamanca) of the Trichoderma strains tested in this study had been terminated. The authors did not have permission to publish work done with these strains and have therefore requested the retraction of this paper. The authors wish to the apologize to the University of Salamanca and to the readers. [ABSTRACT FROM AUTHOR]
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- 2024
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7. A systematic methodological approach to estimate the impacts of a classical biological control agent's dispersal at landscape: Application to fruit fly Bactrocera dorsalis and its endoparasitoid Fopius arisanus.
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Agboka, Komi Mensah, Tonnang, Henri E.Z., Abdel-Rahman, Elfatih M., Kimathi, Emily, Mutanga, Onisimo, Odindi, John, Niassy, Saliou, Mohamed, Samira A., and Ekesi, Sunday
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FRUIT flies , *BIOLOGICAL pest control agents , *ORIENTAL fruit fly , *FRUIT fly control , *ECOLOGICAL models , *ECOLOGICAL niche , *PSYCHOLOGICAL feedback - Abstract
• This paper proposes and describes an interesting and potentially powerful means to validate large-scale biocontrol agent impacts during a Classical biological control (CBC) programme. • The methodology derives the beneficiaries' farmers from the dispersal of parasitoids at a landscape level. • The methodology was applied to the endoparasitoid Fopius arisanus release to control fruit fly Bactrocera dorsalis in Africa. • The study's outcome is appropriate for agriculture stakeholders and development partners to evaluate the benefits of CBC programme. Following the invasion of Africa by the oriental fruit fly, Bactrocera dorsalis , Classical biological control (CBC) has been exploited as a safer alternative for its suppression by the introduction and release of the koinobiont endoparasitoid, Fopius arisanus. Although the parasitoids have been released in several African countries, the extent of their dispersal and the resulting extent in benefits to fruit growers have not yet been elucidated. This paper proposes an innovative, multi-level CBC impact analysis that combines cellular automata (CA) and ecological niche models to estimate parasitoid dispersal ranges and the range of farmers who benefit from it. Firstly, we provided a generic, systematic methodological approach using CA rules incorporated into species distribution. Secondly, the model was used to estimate the dispersal range of the parasitoid, based on the life history and bioecology of the host insect (fruit fly) and the parasitoid. Finally, the parasitoid dispersal coverage was mapped across fruit crops attacked by the target fruit fly, and the number of households that benefited from the parasitoids release programme was extracted from the area of the dispersal. The data was projected across all countries where the parasitoid has been released and validated. In Kenya, the model showed that F. arisanus had covered a total area of 50.34 km2 from the initial point of open field release; and at the continental scale, the model predicted that the parasitoid had covered a total area of 229.97 km2. The model estimated that 351,855 and 3,731,330 households had directly benefited from the release of F. arisanus between 2013 and 2018 in Kenya and at the continental level, respectively. The study's outcome is appropriate for providing feedback information on the impact of CBC to government and development partners to assist in making informed decisions on technological interventions. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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8. Guidelines and framework to assess the feasibility of starting pre-emptive risk assessment of classical biological control agents.
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Avila, Gonzalo A., Seehausen, M. Lukas, Lesieur, Vincent, Chhagan, Asha, Caron, Valerie, Down, Rachel E., Audsley, Neil, Collatz, Jana, Bukovinszki, Tibor, Sabbatini Peverieri, Giuseppino, Tanner, Rob, Maggini, Ramona, Milonas, Panagiotis, McGee, Connor F., Horrocks, Kiran, Herz, Annette, Lemanski, Kathleen, Anfora, Gianfranco, Batistič, Luka, and Bohinc, Tanja
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BIOLOGICAL pest control agents , *RISK assessment , *INTEGRATED pest control , *ARTHROPOD pests , *BIOLOGICAL pest control , *EXTERNALITIES - Abstract
• In this perspective paper we address the concept of pre-emptive biological control as a novel approach to enhance biocontrol preparedness. • We highlight the importance of pre-emptive biological control and provide examples of pre-emptive biological control programmes conducted, or currently underway, against different high-risk pests. • We define a set of aspects that should be considered when selecting a suitable target pest for pre-emptive biocontrol risk assessment. • We provide a set of guidelines and a decision framework to assess the feasibility of conducting pre-emptive risk assessment for candidate biological control agents against high-risk arthropod pests. • We comment on how the proposed guidelines and decision framework will provide biocontrol practitioners with a suitable tool to assess if biocontrol risk assessment against a high-risk pest could be initiated pre-emptively. Non-native invasive arthropod species threaten biodiversity and food security worldwide, resulting in substantial economic, environmental, social and cultural costs. Classical biological control (CBC) is regarded as a cost-effective component of integrated pest management programmes to manage invasive arthropod pests sustainably. However, CBC programmes are traditionally conducted once a pest has established in a new environment, and invariably all research needed to achieve approval to release a biological control agent can take several years. During that time, adverse impacts of the pest accelerate. A pre-emptive biocontrol approach will provide the opportunity to develop CBC for invasive pests before they arrive in the country at risk of introduction and therefore enhance preparedness. A critical aspect of this approach is that risk assessment is carried out in advance of the arrival of the pest. Implementing pre-emptive biocontrol risk assessment means that natural enemies can be selected, screened in containment or abroad and potentially pre-approved prior to a pest establishing in the country at risk, thus improving CBC effectiveness. However, such an approach may not always be feasible. This contribution defines the fundamental prerequisites, principles, and objectives of pre-emptive biocontrol risk assessment. A set of guidelines and a decision framework were developed, which can be used to assess the feasibility of conducting a pre-emptive risk assessment for candidate biological control agents against high-risk arthropod pests. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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9. Systematic cultivar selection for weed biological control risk assessment.
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Lefoe, Greg, Hauser, Cindy E., Steel, Jackie, Slater, Anthony T., Kwong, Raelene M., Lubanga, Umar K., and Rumpff, Libby
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BIOLOGICAL weed control , *WEEDS , *RISK assessment , *CULTIVATED plants , *BIOLOGICAL pest control agents , *NOXIOUS weeds , *NATIVE plants - Abstract
• We reviewed current practice for selecting plant cultivars for host-specificity test lists. • We found cultivar selection and testing is under-reported in peer-reviewed papers. • We propose a decision tool for selecting crop and ornamental cultivars. • The tool considers past testing, cultivar exposure, phylogeny, and sampling capacity. • The decision tool improves transparency, reproducibility, and defensibility of test lists. Classical biological control is important for long-term, sustainable management of invasive species such as weeds. To be acceptable for introduction, new biocontrol agents must not damage crops, native plants, or other valued non-target species. Host-specificity experiments inform risk assessment of new biocontrol agents by prioritising and testing non-target plant species. Susceptibility to damage can also vary between cultivars of the same species, yet current protocols for the selection of test plant species inadequately address cultivar differences. Poor selection increases the risk of failing to detect non-target damage. We developed criteria for prioritising cultivars and a process chart (the 'decision support tool') to guide the selection of cultivars for biological control host-specificity testing. We reviewed and documented current cultivar selection practice published in prominent biological control journals and government documents to further explore current best practice for cultivar selection. To demonstrate the utility of the tool, we then applied the decision support tool to a complex host-specificity testing case study. In our review, most papers either did not mention cultivars of the cultivated plant species being tested, or they provided incomplete descriptions of cultivars without explaining omissions. Only one of 29 papers fully described the method for selecting and prioritising cultivars and reported the results for each cultivar tested. Our application of the process chart to a potato testing case study generated a feasible short-list of cultivars which can be scrutinized and updated. We showed how selections could be made through a collaborative and transparent process involving key stakeholders and decision makers. We have identified an example of under-reporting in classical biological control which, if not addressed, could impede progress in the sustainable management of invasive species. The decision support tool we developed has broad application in weed biological control risk assessment. We demonstrated that the decision tool is easy to use, can account for uncertainty, is adaptable to different species, and is suitable for both small and large cultivar groups irrespective of complexity. Our approach will result in more transparent, defensible, and reproducible cultivar selection practices, leading to greater confidence in biological control risk assessments. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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10. First record of the spatio-temporal variation of Plutella xylostella (Lepidoptera: Plutellidae) and its parasitoids complex in the horticultural area of Córdoba city in central Argentina.
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Espinoza-Gavilanez, Rosita and Grilli, Mariano P.
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DIAMONDBACK moth , *SPATIO-temporal variation , *PLUTELLIDAE , *LEPIDOPTERA , *ICHNEUMONIDAE , *BRACONIDAE - Abstract
• Plutella xylostella is the most destructive pest of horticultural crucifer crops in Córdoba Argentina. • The lack of information on its natural enemies in the region is limiting an IMP approach. • A full description of the dynamics of the pest and its parasitoid complex is presented for the area for the first time. • The potential of our findings for management of the pest is discussed. The diamondback moth, Plutella xylostella (L.) (Plutellidae: Yponomeutoidea) is the most destructive pest in Brassicaceae crops worldwide. This paper describes the status of P. xylostella and its natural enemies in a wide area around Córdoba city in the central region of Argentina. Samples were collected from fifteen horticultural plots near Córdoba City. In each plot, larvae and pupae were obtained from 10 cabbage plants during the spring of 2016 and 2017. Immature specimens were kept until an adult DBM or a parasitoid emerged. Maximum density of immature individuals per plant occurred at different moments in each sampling site, indicating local effects and dynamics of the pest. Higher densities of immature P. xylostella were observed in sites in the north-east horticultural zone of Córdoba city, where most of the farms are located. The percentage of total parasitism also varied between sites and between years but, in general, higher percentages of parasitism were observed at the end of the sampling season. Five parasitoid species were identified: Siphona sp. (Diptera: Tachinidae), Diadegma leontiniae (Hymenoptera: Ichneumonidae), Apanteles piceotrichosus (Hymenoptera: Braconidae) , Oomyzus sokolowskii (Hymenoptera: Eulophidae) and the hyperparasitoid Conura pseudofulvovariegata (Hymenoptera: Chalcididae). Parasitoids behaved in a similar way to P. xylostella. Densities and dynamics were particular to each sampling site. Implications for management are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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11. Behavioural responses of the parasitoid Aphytis melinus to volatiles organic compounds (VOCs) from Aonidiella aurantii on its host fruit Tahitian lime fruit Citrus latifolia.
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Mohammed, Khalid, Agarwal, Manjree, Du, Xin Bob, Newman, James, and Ren, YongLin
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LIME (Fruit) , *CITRUS fruits , *ORGANIC compounds , *VOLATILE organic compounds , *CITRUS , *BIOLOGICAL pest control - Abstract
• 26 volatiles (HIPVs) are characteristic of healthy and CRS-infested lime fruit. • Aphytis melinus prefer CRS-infested lime fruit over the control of no host fruit. • No significant differences for wasps' attraction between healthy and infested fruit. • d -limonene and β-ocimene elicited a strong attraction to wasps at dosages 15 μl/ml. Aphytis melinus DeBach (Hymenoptera: Aphelinidae) is a parasitoid of Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae). However, the cues used by A. melinus for host location have not been extensively investigated. Many studies have shown that mating parasitoids are strongly attracted by specific volatiles from infested plants. This paper investigated the response of A. melinus to volatiles from Tahitian lime fruit infested with A. aurantii through two-choice olfactometer bioassays. First, we identified the chemicals emitting from non-infested and A. aurantii -infested lime fruit via gas chromatography-mass spectrometry analyses and solid phase microextraction and identified 26 volatile organic compounds (VOCs). Eighteen of these were increased by A. aurantii infestation, and one was decreased, whereas five compounds were produced exclusively from infested fruit. Innate positive chemotaxis of mating A. melinus females toward lime fruit and their VOCs was then tested in olfactometer assays. Compared to the control without fruit, female A. melinus showed significantly greater attraction to healthy and A. aurantii -infested lime fruit, while there were no significant differences in the attraction of the parasitoid between healthy fruit or fruit infested with the second and third instar of A. aurantii. Among the two synthetic compounds tested, d -limonene and β -ocimene elicited a strong attraction for parasitoids at tested dosages (15 μl/ml), indicating an intrinsic response to this compound as a short-range attractant. Results from this study suggest that A. melinus parasitoids mainly rely on olfactory cues in host habitat location and that d -limonene and β -ocimene are the major attractants in infested fruit volatiles. Practically, field applications of this volatile may play a significant role in attracting more A. melinus to enhance the efficiency of biological control of A. aurantii in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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12. Field assessment of microbial inoculants to control Rhizoctonia root rot on wheat.
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Barnett, Stephen J., Ballard, Ross A., and Franco, Christopher M.M.
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ROOT rots , *MICROBIAL inoculants , *GRAIN - Abstract
Graphical abstract Highlights • Seed applied microbes assessed for Rhizoctonia root rot control in field. • An alternate row microplot system developed for initial field assessment. • Effective strains then tested in 20 m split-plots for disease control and yield. • Paenibacillus S4 and Streptomyces F5 were equal or better than chemical controls. • Best performing strain reduced root disease 30% and increased yield up to 4.2%. Abstract Rhizoctonia root rot caused by Rhizoctonia solani AG8 is a major disease in dryland cereal crops. Previous research identified a suite of microbes using in planta bioassay screening that are effective as seed-coated inoculants for control of Rhizoctonia root rot on wheat. This paper assessed 23 strains in fields in Australia with a history of naturally occurring R. solani AG8. Due to the patchy nature of Rhizoctonia root rot in the field, a 2-phase split-plot field trial system was used to allow comparison for disease control efficacy in the same disease space. Seed applied strains were first assessed for their ability to reduce Rhizoctonia using 'microplots' which compare adjacent treated and untreated one metre rows. Up to 10% increases in plant growth and a 32% reduction in root disease was measured at eight weeks after sowing. Selected strains were then assessed in 20 m six row (3 + 3) split plots for their effects on early season wheat growth and root damage and for grain yield. A Paenibacillus and a Streptomyces strain were identified which were able to reduce root damage by 20% and 32% and increase grain yield by 4.2% and 2.8%, respectively, compared to untreated controls. The current best registered chemical control for Rhizoctonia root rot reduced root disease by 35% and increased yield by 3.0% in the same trial. [ABSTRACT FROM AUTHOR]
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- 2019
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13. Diversity, plant growth promoting and downy mildew disease suppression potential of cultivable endophytic fungal communities associated with pearl millet.
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Nandhini, M., Rajini, S.B., Udayashankar, A.C., Niranjana, S.R., Lund, Ole S., Shetty, H.S., and Prakash, H.S.
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SEEDLINGS , *ENDOPHYTES , *ENDOSYMBIOSIS , *GROWTH factors , *SCANNING electron microscopy - Abstract
Highlights • Fungal endophytes isolated from leaf, shoot and root of pearl millet varied among different geographic and soil conditions. • All the isolated endophytic fungi belonged to Phylum Ascomycota, among which Fusarium was the most commonly isolated genus. • Molecular authentication and plant growth promoting traits were carried out for representative isolates. • Seed treatment with the endophytes improved the germination percentage and seedling vigour of pearl millet. • Downy mildew incidence was reduced to 36% in endophyte treated seedlings from 89% in control seedlings. Abstract In the present study, endophytic fungi were isolated from different parts of pearl millet crop from different regions of Karnataka. Endophytes were screened for diversity in tissue types, plant growth promoting (PGP) traits and downy mildew disease suppression ability in pearl millet. A total of 202 fungal isolates were isolated from leaves, shoot and root regions. The diversity analysis revealed that the plant harbored diverse fungal groups and the dominant fungi varied according to the sampling regions. The isolates were assigned to 29 fungal species based on morphology and molecular characterization using ITS sequence. All the isolates belonged to the phylum Ascomycota. Fusarium species were the most dominant fungi. Out of 29 representative isolates tested for plant growth promoting traits in vitro and in vivo , seven isolates were observed to improve the growth of pearl millet in comparison to control. Among the seven isolates, Fusarium oxysporum , Trichoderma asperellum and Acremonium sp. were found to suppress the downy mildew disease incidence by 36% in greenhouse conditions. The potent isolates were confirmed to behave as endophytes using pathogenicity, SEM and confocal microscopy experiments. This paper underlines the value of the endophytes as untapped suitable source of beneficial microorganisms that can be used to control pathogens in a sustainable way. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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14. Enhancing the pathogenicity of Arthrobotrys conoides and A. oligospora against Meloidogyne javanica J2 by transferring of protease (Ac1) gene and evaluation of antagonistic capability of transgenic isolates.
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Nourani, Seyedeh Lavin, Goltapeh, Ebrahim Mohammadi, Safaie, Naser, Javaran, Mokhtar Jalali, and Pourjam, Ebrahim
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ANTAGONISTIC fungi , *PROTEOLYTIC enzyme genetics , *ARTHROBOTRYS conoides , *JAVANESE root-knot nematode , *TRANSGENIC organisms , *BIOLOGICAL assay - Abstract
Antagonistic fungi are well-known as viable alternatives to chemical control of root-knot nematodes. In this paper, serine protease Ac1 as an important pathogenicity factor was used to enhance the antagonistic activity of Arthrobotrys conoides and A. oligospora against Meloidogyne javanica J 2 (second stage juveniles). Ac1 gene was extracted from A. conoides and cloned in pCAMBIA1304 vector. The recombinant plasmid was then transferred to these fungi using two strains of Agrobacterium tumefaciens (LBA4404 and AGL1). Transgenic isolates were confirmed by PCR amplification of Hygromycin B resistance gene ( hph ) as selectable marker, protease assay using casein substrate and in vitro bioassay. Transferring of Ac1 gene by homologous recombination to A. conoides , increased protease activity. Our results showed that production of protease in both transgenic species was increased compared to wild type. Bioassay results indicated that pathogenicity rates of transformants, in both the number of traps formed and the number of trapped J 2 , increased compared to the wild type. The results showed that inhibition of root-knot nematode , M. javanica , was markedly increased by transgenic isolates of Arthrobotrys spp. compared to the wild types. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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15. Molecular characterization of interspecific competition of Diachasmimorpha longicaudata (Ashmead) and Fopius arisanus (Sonan) parasitizing the oriental fruit fly, Bactrocera dorsalis (Hendel).
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Liang, Guang Hong, Fu, Lie Qing, Zheng, Jun Xian, Lin, Hao Yu, Lin, Jian Hui, Sim, Sheina B., Jang, Eric B., Heller, Wade P., and Geib, Scott M.
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PARASITIC wasps , *COMPETITION (Biology) , *BIOLOGICAL pest control agents , *ORIENTAL fruit fly , *BRACONIDAE - Abstract
Diachasmimorpha longicaudata (Ashmead) and Fopius arisanus (Sonan), are two of the most abundant and widely used parasitoids for biological control of Bactrocera dorsalis (Hendel) worldwide. However, interspecific competition between them frequently occurs within a single host once they coexit in same orchard, resulting in reduction of their combined impact. However, thus far, it is difficult to characterize these complex interactions. This paper demonstrates qPCR-methods for detection of parasitism for single D. longicaudata , and methods to determine interspecific interaction with F. arisanus . Utilizing qPCR-based methodologies, a species-specific probe was designed for D. longicaudata , which was coupled with a previously published probe for F. arisanus . An assay was developed that is sensitive enough to detect parasitism of solitary D. longicaudata across all developmental stages including one egg per host larva (0.01 ng/40 ng parasitoid/host DNA). The detected parasitism of D. longicaudata was higher than that of using traditional rearing-methods. For the lab-reared and wild strain of multiple species parasitization, qPCR-methods also detected higher parasitism by the above two species from one assay respectively when compared to conventional rearing-based methods. In the later experiment, the majority of D. longicaudata larvae were dying or dead within hollow-like host pupae probably due to interspecific competition. This method is a reliable and robust technique to determine parasitism by a single species or both species of parasitoid across all life stages within one host. It will be useful to evaluate parasitoid combined suppression, and to characterize complex interspecific competition between these two species of parasitoids. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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16. Insect and weed biological control in Hawaii: Recent case studies and trends.
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Ramadan, Mohsen M., Kaufman, Leyla V., and Wright, Mark G.
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BIOLOGICAL control of insects , *NUMBERS of species , *INTRODUCED insects , *INSECT-plant relationships , *BIOLOGICAL weed control , *INTRODUCED species - Abstract
• Selected recent biocontrol successes in Hawaii are reviewed. • Current trends show improved perceptions of biocontrol in Hawaii. • Numbers of biocontrol introductions in Hawaii remain low, in large part because of a lack of quarantine facilities. • The need for a multi-agency biocontrol research facility in Hawaii is underscored. Hawaii has a long history of classical biological control research and implementation. Many successes have been achieved in suppressing invasive insect species and plants though the introduction of insect and plant pathogenic natural enemies. This review paper details selected recent introductions and discusses selected cases highlighting successes with highly impactful invasive species control in diverse environments. The current state of biological control in Hawaii is discussed, including recent trends in numbers of species released, concerns about non-target impacts, and how these are addressed. Research on the biological aspects is thorough, but the ability to expand research to address continuing invasive species issues is constrained largely by infrastructure limitations. Urgent research needs for continued biological control research are identified. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
17. The Brazilian peppertree biological control agent Pseudophilothrips ichini (Thysanoptera: Phlaeothripidae) displays a flexible feeding strategy between foliage and reproductive tissues.
- Author
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Nestle, R., Palacios, J., David, A.S., Read, Q.D., and Wheeler, G.S.
- Subjects
- *
BIOLOGICAL pest control agents , *FLEXIBLE display systems , *THRIPS , *PLANT reproduction , *ANACARDIACEAE , *NOXIOUS weeds - Abstract
[Display omitted] • Thrips chose flush foliage over reproductive tissues. • In the absence of flush foliage, thrips chose reproductive tissues. • Thrips directly damage host reproductive tissues and survive to adulthood. • Tissues differed in their volatile constituents. The biological control agent, Pseudophilothrips ichini, is being released for control of Brazilian peppertree, Schinus terebinthifolia (Anacardiaceae), an invasive weed of natural and agricultural areas of California, Florida, Hawaii, and Texas (USA). The thrips larvae and adults feed on flushed leaves and stems that are produced during the vegetative season of the host. However, during the reproductive season from September to December in Florida, few flushing leaves are available as resources are shunted to plant reproduction. As field releases were being implemented, thrips were found feeding and damaging immature fruits and flowers of their host. We hypothesized that the thrips used volatile organic compounds produced by reproductive tissues to locate and feed on these tissues. When examined under laboratory choice tests, individual thrips or groups of either 20 adults or larvae, chose flushing leaves over all reproductive tissues, female flowers, male flowers, and immature fruit. However, to simulate seasons when few flushing leaves were available, additional choice tests were conducted where flushing leaves were omitted, and only reproductive tissues and a filter paper control were included. Individual thrips or groups of either 20 adults or larvae selected all reproductive tissues over controls. When presented with a choice between immature and mature fruit, thrips chose immature fruit. Thrips caused significant damage to live female flowers, male flowers, and immature fruit, and thrips survival rates were similar when fed flush leaves, female flowers, or male flowers. The thrips responses could be tied to VOC production, which significantly varied among tissue types. Volatile blends from flush leaves that include DMNT, Terpinolene, and δ-Elemene may attract P. ichini whereas those that repel them include α-Thujene, α-Pinene, β-Pinene, Camphene, and β-Phellandrene. These results suggest P. ichini has a flexible feeding strategy and exploits Brazilian peppertree reproductive tissues when few flushing tips were available. Further they suggest thrips feeding will have direct impacts on Brazilian peppertree reproduction. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
18. Biocontrol effects of Brevibacillus laterosporus AMCC100017 on potato common scab and its impact on rhizosphere bacterial communities.
- Author
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Chen, Shengfu, Zhang, Mingshuo, Wang, Jianyu, Lv, Da, Ma, Yanfang, Zhou, Bo, and Wang, Bing
- Subjects
- *
POTATO scab , *BIOLOGICAL pest control , *BREVIBACILLUS brevis , *RHIZOBACTERIA , *BACTERIAL communities - Abstract
Potato common scab (PCS) is an economically important disease caused by Streptomyces spp. which occurs in potato planting areas worldwide. In this paper, pot experiments were conducted in the greenhouse to evaluate the biocontrol effects of Brevibacillus laterosporus AMCC100017 on potato common scab, and to assess the impact of the biocontrol bacterium on soil bacterial communities at four plant growth stages of potato. Results revealed that B. laterosporus AMCC100017 colonized steadily in potato rhizosphere ranging from 5.47 to 6.87 Log 10 CFU g −1 soil detected by real-time PCR. It significantly (P < 0.05) reduced the pathogen population of Streptomyces bottropensis from 4.54 to 4.28 Log 10 CFU g −1 soil in the harvesting stage of potato, decreased the disease severity from 2.60 down to 0.77, and the biocontrol efficacy against common scab reached as great as 70.51%. Meanwhile, the relationship between B. laterosporus AMCC100017 and the functional microorganisms such as actinomycetes, Bacillus spp. and Pseudomonas spp. in the rhizosphere of potato, was discussed based on cultural method and the analyses of terminal restriction fragment length polymorphism (T-RFLP). The adding of B. laterosporus AMCC100017 had only slight transient impact on the native bacteria community in the flowering stage of potato. B. laterosporus AMCC100017 has the promising perspective developing into a biocontrol agent against potato common scab in the field. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
19. Low labor “in vivo” mass rearing method for entomopathogenic nematodes.
- Author
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Testa, Antonio M. and Shields, Elson J.
- Subjects
- *
INSECT nematodes , *INSECT rearing , *BIOLOGICAL pest control agents , *HUMIDITY , *IN vivo studies - Abstract
The wide spread use of biological control agents in commercial agriculture is frequently limited by the high cost of the biological control agents. We describe in this paper an entomopathogenic nematode (EPN) “in vivo” mass rearing method, not based on the White trap concept, which is both “low technology” and “low labor”, reducing the cost of producing large quantities of EPN IJ to the level conducive for use in an area-wide biocontrol program. Rearing temperature has a significant impact on the number of EPN IJ produced per host larvae and the IJ viability at any point in time. Emerged IJs remain within a non-aqueous, high humidity environment with improved oxygen access without extra steps or equipment. Depending on storage conditions, IJs remain viable for 7–14 d without extra labor. Our laboratory has used this rearing method to rear more than 100 billion IJ in the past 8 years to support an area wide biological control program. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
20. Alterations in the proteome as a regulating mechanism for patulin stress by the antagonistic yeast Meyerozyma guilliermondii.
- Author
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Solairaj, Dhanasekaran, Yang, Qiya, Ma, Junfang, Fu, Yu, and Zhang, Hongyin
- Subjects
- *
MEMBRANE proteins , *APPLE blue mold , *PATULIN , *PROTEIN expression , *GENE expression , *YEAST - Abstract
• PAT stress altered the proteome of M. guilliermondii. • PAT up-regulated proteins related to drug resistance and antioxidant stress. • PAT up-regulated proteins related to multidrug transporter and transporter. Meyerozyma guilliermondii is an antagonistic yeast; our research team has recently reported its biocontrol activities against blue mold decay of pears and strong patulin (PAT) reduction ability in vitro. PAT is a harmful mycotoxin produced by some species of Penicillium , Aspergillus , and Byssochlamys. The PAT degradation process and molecular mechanism(s) of M. guilliermondii remain unclear. The data-independent acquisition (DIA) strategies promise a comprehensive, reproducible, digital, qualitative and quantitative record of the proteins present in a sample. Differentially expressed proteins accompanying PAT degradation in M. guilliermondii were observed to investigate PAT reduction mechanisms. The comparative proteomic analysis of M. guilliermondii showed that 136 proteins were up-regulated and 122 were down-regulated upon PAT degradation. The M. guilliermondii's regulation of PAT response mainly includes the up-regulation of (1) growth and reproduction-related protein expression, (2) transcription and translation-related protein expression, (3) resistance-related protein expression, (4) multidrug transporters, (5) anti-oxidative stress-related proteins, (6) the cell wall and cell membrane production-related proteins, and (7) PAT degradation-related protein expression. This paper analyzed M. guilliermondii's molecular response and regulation upon PAT reduction at the gene and protein expression levels. Our results provide a solid foundation for PAT control in fruits and their products by antagonistic yeasts. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
21. Antagonistic effects of volatile organic compounds of Saccharomyces cerevisiae NJ-1 on the growth and toxicity of Aspergillus flavus.
- Author
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Yang, Ting, Wang, Chengzhong, Li, Chenjie, Sun, Rui, and Yang, Mingguan
- Subjects
- *
ASPERGILLUS flavus , *VOLATILE organic compounds , *SACCHAROMYCES cerevisiae , *FIG , *POISONS , *BIOLOGICAL pest control agents , *FUNGAL growth - Abstract
• S. cerevisiae NJ-1 VOCs isolated from pomace of Ficus carica were used as biocontrol agents to against A. flavus. • VOCs has a strong inhibitory effect on the growth and production of aflatoxin. • The cell membrane is the potential target of S. cerevisiae NJ-1 VOCs. • S. cerevisiae NJ-1 VOCs contain alcohols, esters and other substances. Aspergillus flavus is capable of producing highly toxic aflatoxins that can infest grains, cereals and nuts, causing serious economic losses and food safety concerns. Therefore, it is especially necessary to study safe and efficient biological control methods. In this paper, an edible strain of Saccharomyces cerevisiae NJ-1 was isolated from pomace of Ficus carica , the inhibitory effects of S. cerevisiae NJ-1 volatile organic compounds (VOCs) on the growth and aflatoxin production of A. flavus were studied, and the mechanisms of inhibitory effects were initially investigated. The results revealed that the inhibitory effects of S. cerevisiae NJ-1 VOCs on the growth, sporulation, and conidial germination of A. flavus varied significantly with the preculture time. Scanning electron microscopy (SEM) images showed that the morphology of the mycelium of A. flavus treated with VOCs was distorted. Meanwhile, the absorbance at 260 nm and 280 nm had a significant increasing trend, which indicated that the cell membrane was one of the action targets of S. cerevisiae NJ-1 VOCs. A total of nine compounds were identified from S. cerevisiae NJ-1 VOCs by headspace solid-phase microextraction gas chromatography (GC/MS). Among them, 3-methyl-1-butanol showed a significant inhibitory effect on A. flavus and may play an important role in the inhibitory effect of NJ-1 VOCs. The study showed that S. cerevisiae NJ-1 VOCs have great potential to be developed as biopesticides for the control of A. flavus. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
22. The potential for biological control on cryptic plant invasions.
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Canavan, Kim, Canavan, Susan, Harms, Nathan E., Lambertini, Carla, Paterson, Iain D., and Thum, Ryan
- Subjects
- *
PLANT invasions , *PLANT populations , *PLANT capacity , *PLANT species , *BIOLOGICAL pest control , *NATIVE plants , *SPECIES hybridization , *CHEMICAL plants - Abstract
Cryptic invasions can be defined as 'the occurrence of an invasive species or genotype that was not previously recognised as alien in origin or not distinguished from other aliens'. Such invasions can result in negative impacts on the recipient ecosystems and disturb the evolutionary history of native plant populations. Many cryptic invasions have become so problematic that there is a need to implement control measures. This paper explores the potential for biological control to be implemented as a means of managing cryptic invasions. Firstly, the paper defines the different forms of cryptic invasion, differentiating between interspecific and intraspecific invasions; this hierarchy influences how to detect, study and ultimately implement biological control when cryptic invasions occur. Secondly, unique challenges associated with biological control programmes for cryptic invasions are addressed, including: the need for intraspecific level host specificity in agents, the occurrence of hybridisation between native species/lineages and the target weed, the role of enemy release in cryptic invasions in the presence of closely related native plant species/lineages, and a review of potential stakeholder conflicts of interest and legislation. Biological control of cryptic invasions has been shown to be possible, however the process will be more difficult and complex than controlling traditional targets and will likely take up more time and resources. If these challenges are overcome, then biological control programmes against cryptic invasions should be able to proceed and maintain the same standards as traditional biological control programmes. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
23. The current trend in biological control approaches in the mitigation of golden apple snail Pomacea spp.
- Author
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Azmi, Wahizatul Afzan, Khoo, Shing Ching, Ng, Lee Chuen, Baharuddin, Nursalwa, Aziz, Azlina Abd, and Ma, Nyuk Ling
- Subjects
- *
POMACEA canaliculata , *INSECT nematodes , *POMACEA , *PEST control , *TECHNOLOGICAL innovations , *ENTOMOPATHOGENIC fungi - Abstract
• Climate change is expected to worsen GAS infestation and threaten food security. • Entomopathogenic fungi and nematodes are potential GAS biological controls. • Integrated and precision pest management improved pest monitoring system. Golden apple snails (GAS) (Pomacea spp.) is one of the major pests that rampantly invaded many countries and brought a heavy bloom to agricultural cultivation. Their invasion had resulted in huge crop damage and ultimately caused massive economic loss. For the past few decades, many strategies had been developed to overcome the GAS infestation. Among all the strategies, chemical synthetic molluscicides had been the mainstay within the farmer community. Despite their effectiveness in controlling the GAS infestation, extensive use of chemical molluscicides has negative impacts on humans, non-targeted organisms, and the environment. Climate change is expected to hasten the reproduction of GAS, necessitating the development of more sustainable GAS mitigation strategies. This paper examines the current stage of GAS invasion and its implications for global rice production. This review also includes an in-depth discussion of the various potential biological based strategies involved in pest management, and the recent technological breakthroughs in entomopathogenic nematodes and entomopathogenic fungi as molluscicides, integrated pest management, and precision pest management. To summarize, this review provides a potential trend in the use of biocontrol as a substitute for chemically manufactured synthetic molluscicides for the sustainable management of GAS. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
24. Evaluation and optimization of blends for attracting Trichogramma dendrolimi based on semiochemicals mediating tritrophic interactions in the orchard habitat.
- Author
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Zhao, Jinhao, Liang, Minmin, Wang, Zhongyan, Zhao, Yanyan, Cheng, Jingli, and Du, Yongjun
- Subjects
- *
TRICHOGRAMMA , *SEMIOCHEMICALS , *GRAPHOLITA , *ORCHARDS , *BIOLOGICAL pest control , *HERBIVORES , *LADYBUGS - Abstract
• A compound library was built based on the semiochemicals derived from flowers, intact plants, herbivore-attacked plants, and insects in the orchard habitats. • Trichogramma dendrolimi was attracted to 17 volatile compounds when using a Y-tube olfactometer and EAG technology. • Two formulations comprising methyl salicylate and benzaldehyde and supplemented with linalool oxide or cis -3-hexenyl caproate (10:3:3) attracted more T. dendrolimi to orchards than positive (methyl salicylate only) and solvent controls. • In addition to T. dendrolimi , these same formulas also seem to attract other natural enemies in the orchards such as Syrphidae and ladybeetles. Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae) is one of the most important parasitic natural enemies of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) in peach and pear orchards. The artificial rearing T. dendrolimi have been widely used in biological control programs in recent years. However, its actual parasitic effect on the pest in the field is less, so it is important to develop attractants to increase the parasitic efficiency of the parasitoids. T. dendrolimi can be easily attracted by semiochemicals derived from flowers, intact plants, herbivore-attacked plants, and insects in its orchard habitats. In this paper, 73 semiochemicals were evaluated as potential attractants at three concentrations (0.1 mg/mL, 1 mg/mL, and 10 mg/mL) to T. dendrolimi by Y-tube olfactometer bioassays and Electroantennogram (EAG) technology, and then the mixtures of active individual compounds were further tested and evaluated in the field. As a result, 17 individual compounds showed attractive bioactivity to T. dendrolimi. Interestingly, when methyl salicylate and benzaldehyde mixed with linalool oxide or cis -3-hexenyl caproate in a volume ratio of 10:3:3 respectively showed excellent attractant bioactivity for T. dendrolimi in the orchard field. Thus, introducing such parasitoid attractants in orchard habitat may improve the biological control effect to pests. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
25. Dissemination of Lathrolestes ensator (Ichneumonidae), a larval parasite of the European Apple Sawfly, Hoplocampa testudinea (Tenthredinidae), in Eastern North America.
- Author
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Vincent, Charles, Appleby, Margaret, Eaton, Alan, and Lasnier, Jacques
- Subjects
- *
APPLE sawfly , *LARVAL dispersal , *AGRICULTURAL pests , *PARASITES , *APPLE orchards - Abstract
The larval parasite Lathrolestes ensator Brauns (Hymenoptera: Ichneumonidae) has only one known host, Hoplocampa testudinea Klug (Hymenoptera: Tenthredinidae), a pest that attacks only one host: the apple tree. A classical biological program conducted from 1994 to 2001 successfully led to the establishment of L. ensator in Frelighsburg, QC, Canada. This paper reports on work conducted from 2002 to 2015 to disseminate L. ensator in eastern North America. Each year, fruitlets showing secondary damage of H. testudinea were collected in source orchards of Frelighsburg. Random samples of these fruitlets were dissected to estimate % parasitized larvae: the remaining fruitlets were used for releases in apple orchards located in Quebec, Ontario, Nova Scotia and New Hampshire. Collection of fruitlets with secondary damage in participating orchards showed that L. ensator successfully established in Quebec in Henryville, Saint-Hilaire, Magog and St-Georges de Windsor, and in Ontario in Hilton. L. ensator is the only known natural enemy of H. testudinea in North America. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
26. Impact of macrocidins, produced by Phoma macrostoma, on carotenoid profiles of plants.
- Author
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Hubbard, M., Hynes, R.K., and Bailey, K.L.
- Subjects
- *
PHOMA , *CAROTENOIDS , *PLANT species , *HERBICIDES , *ORIGIN of life , *PHYTOTOXINS - Abstract
Phoma macrostoma (Montagne) is a bioherbicide that controls broadleaf weeds such as Canada thistle ( Cirsium arvense L. (Scop.)) and dandelion ( Taraxacum officinale Weber ex F.H. Wigg.), while leaving crop plants, such as wheat ( Triticum aestivum L.) and pumpkin ( Cucurbita L. spp), unharmed. The bioherbicidal activity of P. macrostoma is largely due to the production of phytotoxic secondary metabolites, macrocidins. While macrocidins produce photobleaching symptoms in susceptible plants, the mechanism(s) by which this occurs are not known. The hypothesis that macrocidins inhibit carotenoid biosynthesis was tested by comparing the carotenoid profiles and other physiological parameters of macrocidin-treated Canada thistle, dandelion, pumpkin and wheat with control plants and plants treated with the known carotenoid biosynthesis inhibitor, diflufenican. Only in susceptible plants, macrocidins induced photobleaching symptoms, lowered total chlorophyll content and reduced photosynthetic gas exchange while increasing the percentage of the carotenoid precursor phytoene. While diflufenican also led to chlorosis in dandelion and thistles, its impacts differed from those of macrocidins in that diflufenican-treated dandelion, thistle and pumpkin had increased total carotenoid and carotenoid precursor content compared to the control. Diflufenican-treated dandelion and thistle contained 88 ± 3% and 94 ± 2% phytoene, respectively. In contrast, macrocidins-treated dandelion and thistle (at the higher dose) contained 54 ± 12% and 80 ± 3% phytoene, respectively, while the controls contained only 4 ± 0.5% and 10 ± 1%. The β-carotene to lutein ratio in diflufenican-treated dandelion or thistles did not differ from that of the control, while this ratio was reduced in thistles treated with the higher dose of macrocidins. This paper provides the first proof that macrocidins impact the carotenoid biosynthesis by partially inhibiting the carotenoid biosynthetic enzyme phytoene desaturase (PDS) and at one or more other steps in carotenoid biogenesis. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
27. Biological control of the coffee berry borer: Main natural enemies, control success, and landscape influence.
- Author
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Escobar-Ramírez, Selene, Grass, Ingo, Armbrecht, Inge, and Tscharntke, Teja
- Subjects
- *
BIOLOGICAL pest control , *ANT communities , *PARASITIC wasps , *COFFEE , *MYCOSES , *CROPPING systems - Abstract
• Economic losses due to coffee berry borer (CBB) amount half a billion US-dollar annually. • We review the success of CBB biocontrol in the field considering the role of the landscape context. • Taxonomic groups such as fungi, ants, parasitic wasps, birds and nematodes, can provide successful CBB biocontrol. • Shade coffee systems and nearby forest patches typically enhance CBB biocontrol. • Landscape management can significantly enhance CBB biocontrol but needs further research. Coffee is one of the most important commodities globally and the Coffee Berry Borer (CBB) is its main pest, causing losses of more than half a billion dollars annually. In this systematic review, we quantify the available evidence of successful biological control in coffee agroforestry. There is a recent research trend of switching from the traditional focus on classical biological control to conservation biocontrol, considering a broad range of enemy groups inhabiting the cropping system. We found 19 papers proving CBB biocontrol success in the field and 25 studies suggesting potential biocontrol. Most papers showed effects of fungal infections, followed by papers on ant communities, parasitic Hymenoptera, birds, and nematodes. With respect to local coffee management, arboreal canopy cover providing shade as well as organic practices enhances biocontrol success. Landscape-scale studies are almost missing, although CBB predation by birds can be significant and benefits from the presence of forest patches in the surrounding landscape. Insectivorous birds successfully reduce yield losses by CBB, whereas in many other taxa there is a need for identifying economic impacts of biocontrol. In conclusion, understanding successful coffee management to reduce CBB pest pressure requires more studies on conservation biocontrol, and analyzing the relative importance of local and landscape management for fungal infections as well as for invertebrate and vertebrate predators. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
28. Selecting non-target species for risk assessment of entomophagous biological control agents: Evaluation of the PRONTI decision-support tool.
- Author
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Todd, Jacqui H., Barratt, Barbara I.P., Tooman, Leah, Beggs, Jacqueline R., and Malone, Louise A.
- Subjects
- *
RISK assessment , *BIOLOGICAL control of insects , *ENTOMOPHAGOUS arthropods , *PREDATION , *KIWIFRUIT - Abstract
The release of entomophagous biological control agents can pose risks to non-target invertebrate species in the release area and beyond. Pre-release risk assessment of these agents often involves tests with non-target species; however, selecting appropriate test species can be difficult when there is a large number to choose from. The PRONTI (priority ranking of non-target invertebrates) tool has been developed to aid this selection process. This automated tool prioritises species for testing using five criteria: (1) direct and indirect hazards posed by the agent, (2) likelihood of exposure to the hazards, (3) ecological impacts that may result from that exposure, (4) species’ anthropocentric value and (5) testability. Criteria (1) and (2) produce a risk estimate that drives the ranking process. In a test of PRONTI’s ability to identify non-target species at most risk from a proposed biological control agent, we used a generalist predator already present in New Zealand, the Asian paper wasp Polistes chinensis , as if it were the agent in a hypothetical biocontrol programme aimed at lepidopteran pests in New Zealand kiwifruit orchards. A ranked list of 340 invertebrate taxa known to occur in kiwifruit orchards was produced. To validate the risk estimates for a direct attack by P. chinensis on each taxon, wasps were introduced to kiwifruit orchards and prey taxa identified. Risk estimates were accurate except where identified prey taxa had not previously been recorded from kiwifruit orchards. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
29. Inhibitory efficacy of endophytic Bacillus subtilis EDR4 against Sclerotinia sclerotiorum on rapeseed.
- Author
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Chen, Yafei, Gao, Xiaoning, Chen, Yongxuan, Qin, Huqiang, Huang, Lili, and Han, Qingmei
- Subjects
- *
BACTERIAL inactivation , *BACILLUS subtilis , *SCLEROTINIA sclerotiorum , *RAPESEED , *ENDOPHYTIC bacteria , *CALCIUM pumps , *CELL suspensions , *HYPHOMYCETES , *BACTERIA - Abstract
Stem rot, caused by Sclerotinia sclerotiorum , is a serious disease of rapeseed worldwide. This paper tested the inhibitory effect of an endophytic bacterial Bacillus subtilis strain, EDR4, on the sclerotial germination and hyphal growth of S. sclerotiorum . The cell-free filtrate solution and cell suspension of strain EDR4 were sprayed on rapeseed leaves and stems one day before, at the same time and one day after inoculation in the greenhouse experiments. There was no significant difference in inhibitory efficacy between the cell-free filtrate solution and cell suspension. The best biocontrol efficacy was achieved by spraying either the cell-free filtrate solution or cell suspension at the same time as inoculation. In the field trials, the efficacy of two applications of EDR4 cell suspension at the initial flowering stage and full bloom stage was the best, but there was no significant difference in efficacy between the one-application and two-application treatments during the initial flowering stage. The efficacy decreased gradually with the culture suspension dilutions. Scanning electron microscopy revealed that EDR4 cells significantly suppressed the hyphal growth. The bacterial treatment caused shrink, cytoplasm leakage and irregular tip swelling of fungal hyphae. The hyphal cells in the treated groups had higher numbers of vacuoles in the cytoplasm than the non-treated hyphal cells. The hyphal cytoplasm was disintegrated; the hyphal biomass was reduced; the formation of infection cushions was delayed; and the infection was suppressed after spraying the bacterial culture on rapeseed leaves. The results showed that the EDR4 bacterial strain could be used to control stem rot of rapeseed. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
30. Epiblema tetragonana and Epinotia ustulana (Lepidoptera: Tortricidae), two potential biological control agents for the invasive plant, Rubus ellipticus.
- Author
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Kai Wu, Jun Zhang, Guoan Zhang, and Jianqing Ding
- Subjects
- *
LEPIDOPTERA , *BIOLOGICAL control of insects , *RUBUS , *INVASIVE plants , *CLASSIFICATION of insects , *PLANT species - Abstract
Himalayan yellow raspberry, Rubus ellipticus is one of the world's 100 worst invasive alien species. The plant has become a serious problematic weed in Hawaii, USA and is naturalized in many other countries. Screening of potential biological control agents is being conducted in its native region in Asia. In this paper, we report on the field distribution, abundance and host specificity of two leaf-rolling moth species, Epinotia ustulana and Epiblema tetragonana (Lepidoptera: Tortricidae). In larval non-choice tests both species only developed on plants in the genus Rubus. However, in adult choice oviposition tests, both leaf rollers showed a strong preference for R. ellipticus over other species. Furthermore, leaf-rolls by these two insects were only found on R. ellipticus in the field. These results indicate the moths have a narrow host range. Our field surveys also showed that both moth species are widely distributed in Yunnan Province, southeastern China, with up to 115 leaf rolls per plant, suggesting high levels of damage. These findings indicate that the two insects have considerable potential for biological control of R. ellipticus, though further host range tests should be conducted using more native plant species in Hawaii. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
31. Enhancing the biological control potential of Steinernema feltiae with protection from desiccation and UV radiation.
- Author
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Acar, Ismet and Sipes, Brent
- Subjects
- *
ULTRAVIOLET radiation , *INSECT pests , *INSECT nematodes , *INSECT pest control , *RADIATION protection , *TITANIUM dioxide nanoparticles , *INSECTICIDES , *DRYING agents - Abstract
• P-amino benzoic acid and octyl methoxycinnamate are not toxic to Steinernema feltiae. • UV absorbing chemicals protect Steinernema feltiae from adverse effects up to 12 h. • A desiccant and UV protectant mix prolongs the ability of Steinernema feltiae to infect insects on leaves. • Steinernema feltiae mixed with desiccant and UV protectants increases potential for foliar pest control. Entomopathogenic nematodes (EPNs) are obligate parasites of insects. EPNs generally have a broad host range, are easily mass reared, and can kill some insects within 48 h. EPNs are safe for vertebrates, plants, and other non-target organisms. However, EPNs have disadvantages that make them less effective against foliar insect pests such as sensitivity to desiccation, ultraviolet (UV) radiation, and high temperatures. The goal of this research was to improve the efficacy of aboveground application of Steinernema feltiae by protecting the nematodes against desiccation and UV radiation. The objectives were to evaluate the effect of UV chemical protectants on S. feltiae viability and demonstrate enhanced insect control with S. feltiae formulated to protect them against UV radiation and desiccation. The UV radiation protectant chemicals P-amino benzoic acid (PABA), octyl methoxycinnamate (OMC), Congo red, titanium dioxide, and zinc oxide were not toxic to mealworm larvae nor the EPNs. PABA, OMC, Congo red, titanium dioxide, and zinc oxide protected Infective Juveniles (IJ) of S. feltiae exposed to UV light for 0, 4, 8 and 12 hrs. After 48 hrs exposure, PABA afforded the greatest protection to S. feltiae compared to other chemicals. OMC provided the second greatest protection to the S. feltiae compared to other chemicals. The UV protectants PABA and OMC were individually combined with Barricade® fire gel, a desiccant protectant, and IJs of S. feltiae were added to the mixture. The IJs were exposed to full spectra UV light in the laboratory for up to 12 hrs before introduction of a mealworm host. The subsequent number of dead mealworm larvae on filter paper or on detached leaves was greatest in the combination treatments of OMC + Barricade and PABA + Barricade and lowest in water controls demonstrating the protection afforded to S. feltiae. The survival of S. feltiae can be enhanced when applied with a desiccant protectant such as Barricade and a chemical such as PABA or OMC to protect against UV radiation. The protection afforded to the IJ by these chemicals allows for greater infection and mortality of target insect pests. The formulation of IJs with desiccant and UV radiation protection will allow the greater use of S. feltiae for the management of foliar insect pests. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
32. Biological control agents against the cabbage stem flea beetle in oilseed rape crops.
- Author
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Hoarau, Claire, Campbell, Heather, Prince, Gillian, Chandler, Dave, and Pope, Tom
- Subjects
- *
FLEA beetles , *BIOLOGICAL pest control agents , *CABBAGE , *OILSEEDS , *INSECT nematodes , *INTEGRATED pest control , *PEST control - Abstract
• The cabbage stem flea beetle is an economically important pest of oilseed rape. • Control using only conventional insecticides often ineffective. • Entomopathogens and natural enemies are potentially effective biocontrol agents. • Additional research needed to create integrated pest management programs. • Research gaps: need to understand interactions between agents to optimize control. The cabbage stem flea beetle (CSFB 1 1 CSFB: cabbage stem flea beetle.) Psylliodes chrysocephala Linnaeus is the most important pest of oilseed rape (Brassica napus) crops in Europe. Control has become more difficult since the European Union ban in 2013 on the use of neonicotinoid seed treatments. This situation is made more challenging by the development of resistance to pyrethroid insecticides, the only remaining conventional synthetic insecticides with which to control CSFB. The purpose of this paper is to review the potential of biological alternatives to the use of synthetic pesticides for the control of the CSFB. Only a small number of studies have investigated biological control agents against CSFB itself. More research has, however, been published on two other, closely related chrysomelid pests of brassica crops that have similar life cycles, namely the crucifer flea beetle Phyllotreta cruciferae and the striped flea beetle Phyllotreta striolata , which enable us to extrapolate reasonably across to CSFB. The biological control agents investigated include entomopathogenic fungi (EPF 2 2 EPF: entomopathogenic fungi.) such as Metarhizium anisopliae and Beauveria bassiana , entomopathogenic nematodes (EPN 3 3 EPN: entomopathogenic nematode.) such as Steinernema feltiae and Steinernema carpocapsae , parasitoids such as Microctonus brassicae and predators such as the ground beetle Trechus quadristriatus. Results vary depending on the setting (laboratory versus field), but several biological control agents investigated resulted in CSFB mortality greater than 50% under laboratory conditions. The biological control of the CSFB shows potential as a viable alternative to the use of conventional synthetic insecticides. Nonetheless, many research gaps remain, as current research has focused largely on crucifer flea beetle and striped flea beetle, with comparatively few studies investigating the potential of biological controls against the CSFB. The research published to date on CSFB has been limited to a small number of species of EPN and EPF with little work investigating the potential of parasitoids and predators. More field studies using EPF are required, while in contrast laboratory studies are underrepresented for EPN. Further research is required, testing existing and new strains of fungi and nematodes, exploring the potential of endophytic fungi, enhancing the formulation and application of biological control for use in inundative strategies, and investigating the potential of conservation biological control. Effective biological control agents should ultimately be combined with cultural control methods in Integrated Pest Management (IPM 4 4 IPM: Integrated Pest Management.) systems for the sustainable management of this pest. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
33. Efficacy of entomopathogenic nematodes against Tuta absoluta.
- Author
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Ben Husin, Taha O. and Port, Gordon R.
- Subjects
- *
INSECT nematodes , *INTEGRATED pest control , *HUMIDITY control , *HUMIDITY , *PLANT parasites , *HETERORHABDITIS - Abstract
• Entomopathogenic nematodes can control tomato leafminer. • Relative humidity affected control by entomopathogenic nematodes. • Different nematode species performed differently, interacting with temperature. • Late instar larvae of the leafminer were easier to control. The South American tomato pinworm, Tuta absoluta (Meyrick) is one of the most serious insect pests of tomato plants. Current control strategies for T. absoluta primarily involve the use of insecticides, but increasing resistance in field populations has prompted research on alternative control measures. Biological control with entomopathogenic nematodes (EPNs) can be an alternative or one component of an Integrated Pest Management programme. In foliar application, EPNs encounter many factors that affect their survival and efficacy. This paper reports investigations into some of these factors for several EPN species; relative humidity (RH), temperature, time required by EPNs to enter a leaf and number of applications in whole leaf bioassays on tomato leaves. RH was the most important factor; EPNs efficacy and survival decreased as RH declined. Steinernema feltiae was the most effective species followed by Steinernema carpocapsae then Heterorhabditis bacteriophora. Steinernema carpocapsae survived better at low RH than S. feltiae. The two Steinernema species induced similar mortality at 25 °C, but S. feltiae was more virulent at lower temperatures (15 and 20 °C) while S. carpocapsae was more virulent at higher temperatures (30 and 35 °C). First and second instar larvae of T. absoluta required more applications compared to third and fourth instar larvae. The species of EPN used to control T. absoluta requires careful selection in relation to the temperature and relative humidity environment of the crop to maximise efficacy. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
34. The response strategies of Colletotrichum gloeosporioides s.s. due to the stress caused by biological control agent Bacillus amyloliquefaciens deciphered by transcriptome analyses.
- Author
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Wang, Qing-Hai, Ji, Yan-Ping, Qu, Yong-Yun, Qi, Yu-Kun, Li, De-Wei, Liu, Zhen-Yu, and Wu, Xiao-Qin
- Subjects
- *
COLLETOTRICHUM gloeosporioides , *BACILLUS amyloliquefaciens , *BIOLOGICAL pest control , *AMINO acid metabolism , *BIOTRANSFORMATION (Metabolism) , *GENE expression , *EFFLUX (Microbiology) - Abstract
• In the interaction system, the DEGs of C. gloeosporioides s.s. were analyzed. • The response model of C. gloeosporioides s.s. to B. amyloliquefaciens was discussed. • The hypothetical response strategies of C. gloeosporioides s.s. was validated. Walnut is cultivated all over the world for its precious woody nut and edible oil. Walnut anthracnose caused by Colletotrichum spp. is a disastrous disease in the walnut plantation. In China, this disease is difficult to control. The efficacies of the traditional preventing and controlling measures are inadequate. It causes serious losses every year. In the interaction systems of 'antagonistic organism-pathogen', the response mechanisms of the pathogen to the stress of antagonistic organisms were largely unknown. To understand the response mechanisms of walnut anthracnose pathogen, Colletotrichum gloeosporioides sensu stricto (s.s.) TS-09R was treated with Bacillus amyloliquefaciens , and RNAseq gene expression analyses were performed. A total of 610 genes expressed differentially (DEGs). Among these genes, 387 genes were up-regulated and 223 genes were down-regulated. Gene ontology (GO) analysis showed that 409 DEGs involved in the categories of biological process, and cellular component. The KEGG pathway enrichment analysis showed that all up-regulated DEGs were enriched in amino acid metabolism, biosynthesis of other secondary metabolites, and xenobiotics biodegradation and metabolism. Further analyses indicated that C. gloeosporioides s.s. TS-09R up-expressed significantly some DEGs associated with cell membrane synthesis and, or maintaining stabilization, antioxidant and anti-stress to build the cell membrane, maintain the normal physiological function of cells. At the same time, it improved detoxification efficiency and reduced its sensitivity to the exogenous antimicrobial substance (EAS). It also improved the activity of the efflux pump translocating EAS out of the cells, reduced accumulation, and minimized injuries to cells. C. gloeosporioides s.s. TS-09R also up-expressed significantly genes associated with sporulation to promote spore production for survival in adversity. C. gloeosporioides s.s. TS-09R recruited numerous genes to respond to or resist the biocontrol of B. amyloliquefaciens. The response model was a holistic and complex network involving multiple genes and multiple signaling pathways. Additionally, the glutathione-S-transferases (GST) activities of C. gloeosporioides s.s. TS-09R, TS-09 cultured for 5 days and 9 days were calculated, and the GST activity had a similar change trend to the GST-related gene expression. The result indicated that the hypothetical response strategies were reliable. In this paper, we provided new insights into the onset of the interaction system of ' C. gloeosporioides s.s. – B. amyloliquefaciens '. The results will contribute to exploring comprehensively the mechanism of B. amyloliquefaciens according to the response mechanisms of C. gloeosporioides s.s. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
35. Biocontrol of the cat flea, Ctenocephalides felis, by entomopathogenic nematodes and fungi.
- Author
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Samish, Michael, Rot, Asael., Gindin, Galina, Ment, Dana, Behar, Adi, and Glazer, Itamar
- Subjects
- *
CAT flea , *ENTOMOPATHOGENIC fungi , *INSECT nematodes , *FLEAS , *BIOLOGICAL pest control , *RHABDITIDA , *NEMATODES - Abstract
• Entomopathogenic nematodes and fungi kill all cat flea stages except eggs. • Nematodes are more virulent against pre-imaginal stages, fungi against adults. • Efficacy depends on temperature, % RH and substrate type. The cat flea, Ctenocephalides felis (Bouche) (Siphonaptera: Pulicidae), is the most important ectoparasite of domestic pets. Its control is mainly based on chemical insecticides. In this study, the potential of fungi and nematodes to control this pest was evaluated. The various life stages of the cat flea were exposed to several variables: strains and species of entomopathogenic nematodes and fungi at different ambient temperatures and levels of relative humidity (RH), as well as in\on filter paper, sand or carpet as substrates. The nematode Steinernema feltiae (Nematoda: Steinernematidae) was most virulent against flea larvae, cocoons and adults, and the nematode Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) was highly effective against flea cocoons on all substrates evaluated. Overall, the nematodes were most effective at 28o C and 95% RH. The fungus Metarhizium robertsii 2575 (Bischoff) (Hypocreales: Clavicipitaceae), was highly virulent against adult fleas. Flea eggs were resistant to both nematodes and the fungus evaluated. The results indicate high potential for use of microbial control agents against cat fleas. While the fungus, M. robertsii , could be effective in killing adult fleas on infested vertebrates, the nematodes S. feltiae and H. bacteriophora could be successful in controlling pre-imaginal stages on the soil. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
36. Biological control of the coffee berry borer: Main natural enemies, control success, and landscape influence
- Author
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Teja Tscharntke, Selene Escobar-Ramírez, Ingo Grass, and Inge Armbrecht
- Subjects
2. Zero hunger ,0106 biological sciences ,Canopy ,Arboreal locomotion ,Agroforestry ,Range (biology) ,Biological pest control ,Insectivore ,15. Life on land ,Biology ,01 natural sciences ,Predation ,010602 entomology ,13. Climate action ,Insect Science ,PEST analysis ,Cropping system ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
Coffee is one of the most important commodities globally and the Coffee Berry Borer (CBB) is its main pest, causing losses of more than half a billion dollars annually. In this systematic review, we quantify the available evidence of successful biological control in coffee agroforestry. There is a recent research trend of switching from the traditional focus on classical biological control to conservation biocontrol, considering a broad range of enemy groups inhabiting the cropping system. We found 19 papers proving CBB biocontrol success in the field and 25 studies suggesting potential biocontrol. Most papers showed effects of fungal infections, followed by papers on ant communities, parasitic Hymenoptera, birds, and nematodes. With respect to local coffee management, arboreal canopy cover providing shade as well as organic practices enhances biocontrol success. Landscape-scale studies are almost missing, although CBB predation by birds can be significant and benefits from the presence of forest patches in the surrounding landscape. Insectivorous birds successfully reduce yield losses by CBB, whereas in many other taxa there is a need for identifying economic impacts of biocontrol. In conclusion, understanding successful coffee management to reduce CBB pest pressure requires more studies on conservation biocontrol, and analyzing the relative importance of local and landscape management for fungal infections as well as for invertebrate and vertebrate predators.
- Published
- 2019
37. Biological control ginseng grey mold and plant colonization by antagonistic bacteria isolated from rhizospheric soil of Panax ginseng Meyer.
- Author
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Sun, Zhuo, Yang, Li-min, Han, Mei, Han, Zhong-ming, Yang, Li, Cheng, Lin, Yang, Xiao, and Lv, Ze-liang
- Subjects
- *
GINSENG , *PLANT colonization , *PLANT growth , *BIOLOGICAL pest control , *PLANT growth promoting substances , *BIOFERTILIZERS , *ANTIFUNGAL agents , *BACILLUS amyloliquefaciens - Abstract
• Bacillus amyloliquefaciens SW-34 exerted the broad-spectrum antibiotic activity. • SW-34 established a population and stable colonization in the ginseng plants. • SW-34 suppressed disease lesions of ginseng grey mold with strong control efficacy. Botrytis cinerea Pers.ex Fr. is a common soil borne fungal pathogen that infects economic crops, such as ginseng, worldwide. One ideal strategy for controlling B. cinerea is to develop and use beneficial rhizobacteria. The goal of this study was to assess the potential of rhizospheric bacteria as antifungal agents against ginseng grey mold disease. In this study, 169 bacterial strains isolated from rhizospheric soil of ginseng plants were screened using the K-B paper dispersion method and the Oxford cup plate assay. Subsequently, strain SW-34 was selected as a potential stock for biocontrol due to the broad-spectrum antibiotic activity of the SW-34 fermentation liquor against pathogens. To assess the antifungal efficacy of SW-34 against ginseng grey mold as well as its ginseng growth promotion abilities, pot experiments were performed under plastic greenhouse conditions. The morphology, physiological and biochemical characteristics, 16S rRNA and gyrB gene sequence were assessed to for the taxonomic characterization of strain SW-34. The results showed that, SW-34 (which was identified as Bacillus amyloliquefaciens) exhibited an antagonistic activity against B. cinerea of 85.13% and also provided broad-spectrum antibiotic activity. Inoculation of the SW-34 cell suspension suppressed disease lesions caused by ginseng grey mold with a strong control efficacy of 72.29%, which was significantly higher than that of the Mancozeb 70% WP fungicide treatment (p < 0.05). Moreover, SW-34 exhibited high cell densities in ginseng plants (root, leaf and stem) and promoted ginseng plant growth. Because the B. amyloliquefaciens SW-34 successfully inhibited ginseng grey mold, the results of our study provides a basis for the potential biocontrol of ginseng grey mold caused by B. cinerea. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
38. First record of the spatio-temporal variation of Plutella xylostella (Lepidoptera: Plutellidae) and its parasitoids complex in the horticultural area of Córdoba city in central Argentina
- Author
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Mariano Pablo Grilli and Rosita Espinoza-Gavilanez
- Subjects
Ichneumonidae ,Horticulture ,Eulophidae ,biology ,Plutellidae ,Insect Science ,Siphona ,Plutella ,Tachinidae ,biology.organism_classification ,Agronomy and Crop Science ,Braconidae ,Chalcididae - Abstract
The diamondback moth, Plutella xylostella (L.) (Plutellidae: Yponomeutoidea) is the most destructive pest in Brassicaceae crops worldwide. This paper describes the status of P. xylostella and its natural enemies in a wide area around Cordoba city in the central region of Argentina. Samples were collected from fifteen horticultural plots near Cordoba City. In each plot, larvae and pupae were obtained from 10 cabbage plants during the spring of 2016 and 2017. Immature specimens were kept until an adult DBM or a parasitoid emerged. Maximum density of immature individuals per plant occurred at different moments in each sampling site, indicating local effects and dynamics of the pest. Higher densities of immature P. xylostella were observed in sites in the north-east horticultural zone of Cordoba city, where most of the farms are located. The percentage of total parasitism also varied between sites and between years but, in general, higher percentages of parasitism were observed at the end of the sampling season. Five parasitoid species were identified: Siphona sp. (Diptera: Tachinidae), Diadegma leontiniae (Hymenoptera: Ichneumonidae), Apanteles piceotrichosus (Hymenoptera: Braconidae), Oomyzus sokolowskii (Hymenoptera: Eulophidae) and the hyperparasitoid Conura pseudofulvovariegata (Hymenoptera: Chalcididae). Parasitoids behaved in a similar way to P. xylostella. Densities and dynamics were particular to each sampling site. Implications for management are discussed.
- Published
- 2019
39. Behavioural responses of the parasitoid Aphytis melinus to volatiles organic compounds (VOCs) from Aonidiella aurantii on its host fruit Tahitian lime fruit Citrus latifolia
- Author
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Xin Bob Du, Manjree Agarwal, Yonglin Ren, Khalid Mohammed, and James Newman
- Subjects
0106 biological sciences ,biology ,fungi ,biology.organism_classification ,Diaspididae ,Aphytis melinus ,01 natural sciences ,Attraction ,Parasitoid ,010602 entomology ,Horticulture ,Positive chemotaxis ,Aphelinidae ,Olfactometer ,Insect Science ,parasitic diseases ,Agronomy and Crop Science ,010606 plant biology & botany ,Aonidiella aurantii - Abstract
Aphytis melinus DeBach (Hymenoptera: Aphelinidae) is a parasitoid of Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae). However, the cues used by A. melinus for host location have not been extensively investigated. Many studies have shown that mating parasitoids are strongly attracted by specific volatiles from infested plants. This paper investigated the response of A. melinus to volatiles from Tahitian lime fruit infested with A. aurantii through two-choice olfactometer bioassays. First, we identified the chemicals emitting from non-infested and A. aurantii-infested lime fruit via gas chromatography-mass spectrometry analyses and solid phase microextraction and identified 26 volatile organic compounds (VOCs). Eighteen of these were increased by A. aurantii infestation, and one was decreased, whereas five compounds were produced exclusively from infested fruit. Innate positive chemotaxis of mating A. melinus females toward lime fruit and their VOCs was then tested in olfactometer assays. Compared to the control without fruit, female A. melinus showed significantly greater attraction to healthy and A. aurantii-infested lime fruit, while there were no significant differences in the attraction of the parasitoid between healthy fruit or fruit infested with the second and third instar of A. aurantii. Among the two synthetic compounds tested, d-limonene and β-ocimene elicited a strong attraction for parasitoids at tested dosages (15 μl/ml), indicating an intrinsic response to this compound as a short-range attractant. Results from this study suggest that A. melinus parasitoids mainly rely on olfactory cues in host habitat location and that d-limonene and β-ocimene are the major attractants in infested fruit volatiles. Practically, field applications of this volatile may play a significant role in attracting more A. melinus to enhance the efficiency of biological control of A. aurantii in the future.
- Published
- 2019
40. Field assessment of microbial inoculants to control Rhizoctonia root rot on wheat
- Author
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Christopher M. M. Franco, Ross Ballard, and Stephen J. Barnett
- Subjects
0106 biological sciences ,biology ,Crop yield ,fungi ,Biological pest control ,Biocontrol ,food and beverages ,Sowing ,field trials ,biology.organism_classification ,Rhizoctonia ,01 natural sciences ,Streptomyces ,Rhizoctonia solani ,010602 entomology ,Paenibacillus ,Horticulture ,wheat ,Insect Science ,Root rot ,Agronomy and Crop Science ,Microbial inoculant ,010606 plant biology & botany - Abstract
© 2019 Elsevier Inc. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 12 month embargo from date of publication (February 2019) in accordance with the publisher’s archiving policy, Rhizoctonia root rot caused by Rhizoctonia solani AG8 is a major disease in dryland cereal crops. Previous research identified a suite of microbes using in planta bioassay screening that are effective as seed-coated inoculants for control of Rhizoctonia root rot on wheat. This paper assessed 23 strains in fields in Australia with a history of naturally occurring R. solani AG8. Due to the patchy nature of Rhizoctonia root rot in the field, a 2-phase split-plot field trial system was used to allow comparison for disease control efficacy in the same disease space. Seed applied strains were first assessed for their ability to reduce Rhizoctonia using ‘microplots’ which compare adjacent treated and untreated one metre rows. Up to 10% increases in plant growth and a 32% reduction in root disease was measured at eight weeks after sowing. Selected strains were then assessed in 20 m six row (3 + 3) split plots for their effects on early season wheat growth and root damage and for grain yield. A Paenibacillus and a Streptomyces strain were identified which were able to reduce root damage by 20% and 32% and increase grain yield by 4.2% and 2.8%, respectively, compared to untreated controls. The current best registered chemical control for Rhizoctonia root rot reduced root disease by 35% and increased yield by 3.0% in the same trial.
- Published
- 2019
41. Diversity, plant growth promoting and downy mildew disease suppression potential of cultivable endophytic fungal communities associated with pearl millet
- Author
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Siddapura Ramachandrappa Niranjana, Sollepura B Rajini, M. Nandhini, H. S. Shetty, Ole Lund, A. C. Udayashankar, and Harishchandra S. Prakash
- Subjects
0106 biological sciences ,0301 basic medicine ,Fusarium ,biology ,food and beverages ,engineering.material ,biology.organism_classification ,01 natural sciences ,Plant use of endophytic fungi in defense ,Crop ,03 medical and health sciences ,030104 developmental biology ,Insect Science ,Fusarium oxysporum ,Shoot ,Botany ,engineering ,Downy mildew ,Beneficial organism ,Agronomy and Crop Science ,Pearl ,010606 plant biology & botany - Abstract
In the present study, endophytic fungi were isolated from different parts of pearl millet crop from different regions of Karnataka. Endophytes were screened for diversity in tissue types, plant growth promoting (PGP) traits and downy mildew disease suppression ability in pearl millet. A total of 202 fungal isolates were isolated from leaves, shoot and root regions. The diversity analysis revealed that the plant harbored diverse fungal groups and the dominant fungi varied according to the sampling regions. The isolates were assigned to 29 fungal species based on morphology and molecular characterization using ITS sequence. All the isolates belonged to the phylum Ascomycota. Fusarium species were the most dominant fungi. Out of 29 representative isolates tested for plant growth promoting traits in vitro and in vivo, seven isolates were observed to improve the growth of pearl millet in comparison to control. Among the seven isolates, Fusarium oxysporum, Trichoderma asperellum and Acremonium sp. were found to suppress the downy mildew disease incidence by 36% in greenhouse conditions. The potent isolates were confirmed to behave as endophytes using pathogenicity, SEM and confocal microscopy experiments. This paper underlines the value of the endophytes as untapped suitable source of beneficial microorganisms that can be used to control pathogens in a sustainable way.
- Published
- 2018
42. Enhancing the pathogenicity of Arthrobotrys conoides and A. oligospora against Meloidogyne javanica J2 by transferring of protease (Ac1) gene and evaluation of antagonistic capability of transgenic isolates
- Author
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Ebrahim Pourjam, Seyedeh Lavin Nourani, Naser Safaie, Ebrahim Mohammadi Goltapeh, and Mokhtar Jalali Javaran
- Subjects
0301 basic medicine ,Protease ,biology ,medicine.medical_treatment ,Wild type ,Agrobacterium tumefaciens ,biology.organism_classification ,Arthrobotrys ,Microbiology ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,Insect Science ,medicine ,Bioassay ,Agronomy and Crop Science ,Hygromycin B ,Meloidogyne javanica ,Selectable marker - Abstract
Antagonistic fungi are well-known as viable alternatives to chemical control of root-knot nematodes. In this paper, serine protease Ac1 as an important pathogenicity factor was used to enhance the antagonistic activity of Arthrobotrys conoides and A. oligospora against Meloidogyne javanica J2 (second stage juveniles). Ac1 gene was extracted from A. conoides and cloned in pCAMBIA1304 vector. The recombinant plasmid was then transferred to these fungi using two strains of Agrobacterium tumefaciens (LBA4404 and AGL1). Transgenic isolates were confirmed by PCR amplification of Hygromycin B resistance gene (hph) as selectable marker, protease assay using casein substrate and in vitro bioassay. Transferring of Ac1 gene by homologous recombination to A. conoides, increased protease activity. Our results showed that production of protease in both transgenic species was increased compared to wild type. Bioassay results indicated that pathogenicity rates of transformants, in both the number of traps formed and the number of trapped J2, increased compared to the wild type. The results showed that inhibition of root-knot nematode, M. javanica, was markedly increased by transgenic isolates of Arthrobotrys spp. compared to the wild types.
- Published
- 2018
43. Molecular characterization of interspecific competition of Diachasmimorpha longicaudata (Ashmead) and Fopius arisanus (Sonan) parasitizing the oriental fruit fly, Bactrocera dorsalis (Hendel)
- Author
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Guang Hong Liang, Scott M. Geib, Hao Yu Lin, Jun Xian Zheng, Wade P. Heller, Sheina B. Sim, Jian Hui Lin, Eric B. Jang, and Lie Qing Fu
- Subjects
0106 biological sciences ,Larva ,Host (biology) ,fungi ,Biological pest control ,Zoology ,Parasitism ,Interspecific competition ,Biology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Bactrocera dorsalis ,Parasitoid ,Pupa ,010602 entomology ,Insect Science ,Agronomy and Crop Science - Abstract
Diachasmimorpha longicaudata (Ashmead) and Fopius arisanus (Sonan), are two of the most abundant and widely used parasitoids for biological control of Bactrocera dorsalis (Hendel) worldwide. However, interspecific competition between them frequently occurs within a single host once they coexit in same orchard, resulting in reduction of their combined impact. However, thus far, it is difficult to characterize these complex interactions. This paper demonstrates qPCR-methods for detection of parasitism for single D. longicaudata, and methods to determine interspecific interaction with F. arisanus. Utilizing qPCR-based methodologies, a species-specific probe was designed for D. longicaudata, which was coupled with a previously published probe for F. arisanus. An assay was developed that is sensitive enough to detect parasitism of solitary D. longicaudata across all developmental stages including one egg per host larva (0.01 ng/40 ng parasitoid/host DNA). The detected parasitism of D. longicaudata was higher than that of using traditional rearing-methods. For the lab-reared and wild strain of multiple species parasitization, qPCR-methods also detected higher parasitism by the above two species from one assay respectively when compared to conventional rearing-based methods. In the later experiment, the majority of D. longicaudata larvae were dying or dead within hollow-like host pupae probably due to interspecific competition. This method is a reliable and robust technique to determine parasitism by a single species or both species of parasitoid across all life stages within one host. It will be useful to evaluate parasitoid combined suppression, and to characterize complex interspecific competition between these two species of parasitoids.
- Published
- 2018
44. Efficacy of entomopathogenic nematodes against Tuta absoluta
- Author
-
Taha O. Ben Husin and Gordon Port
- Subjects
Integrated pest management ,Larva ,biology ,fungi ,Biological pest control ,food and beverages ,biology.organism_classification ,Toxicology ,Crop ,Insect Science ,Heterorhabditis bacteriophora ,Bioassay ,Instar ,Tuta absoluta ,Agronomy and Crop Science - Abstract
Background The South American tomato pinworm, Tuta absoluta (Meyrick) is one of the most serious insect pests of tomato plants. Current control strategies for T. absoluta primarily involve the use of insecticides, but increasing resistance in field populations has prompted research on alternative control measures. Biological control with entomopathogenic nematodes (EPNs) can be an alternative or one component of an Integrated Pest Management programme. In foliar application, EPNs encounter many factors that affect their survival and efficacy. This paper reports investigations into some of these factors for several EPN species; relative humidity (RH), temperature, time required by EPNs to enter a leaf and number of applications in whole leaf bioassays on tomato leaves. Results RH was the most important factor; EPNs efficacy and survival decreased as RH declined. Steinernema feltiae was the most effective species followed by Steinernema carpocapsae then Heterorhabditis bacteriophora. Steinernema carpocapsae survived better at low RH than S. feltiae. The two Steinernema species induced similar mortality at 25 °C, but S. feltiae was more virulent at lower temperatures (15 and 20 °C) while S. carpocapsae was more virulent at higher temperatures (30 and 35 °C). First and second instar larvae of T. absoluta required more applications compared to third and fourth instar larvae. Conclusion The species of EPN used to control T. absoluta requires careful selection in relation to the temperature and relative humidity environment of the crop to maximise efficacy.
- Published
- 2021
45. Biocontrol effects of Brevibacillus laterosporus AMCC100017 on potato common scab and its impact on rhizosphere bacterial communities
- Author
-
Wang Jianyu, Chen Shengfu, Ma Yanfang, Zhang Mingshuo, Bing Wang, Bo Zhou, and Da Lv
- Subjects
0106 biological sciences ,0301 basic medicine ,Rhizosphere ,education.field_of_study ,Common scab ,Microorganism ,fungi ,Population ,Pseudomonas ,Biological pest control ,food and beverages ,Streptomyces bottropensis ,Biology ,biology.organism_classification ,01 natural sciences ,03 medical and health sciences ,Horticulture ,Terminal restriction fragment length polymorphism ,030104 developmental biology ,Agronomy ,Insect Science ,education ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
Potato common scab (PCS) is an economically important disease caused by Streptomyces spp. which occurs in potato planting areas worldwide. In this paper, pot experiments were conducted in the greenhouse to evaluate the biocontrol effects of Brevibacillus laterosporus AMCC100017 on potato common scab, and to assess the impact of the biocontrol bacterium on soil bacterial communities at four plant growth stages of potato. Results revealed that B. laterosporus AMCC100017 colonized steadily in potato rhizosphere ranging from 5.47 to 6.87 Log10 CFU g−1 soil detected by real-time PCR. It significantly (P
- Published
- 2017
46. Low labor 'in vivo' mass rearing method for entomopathogenic nematodes
- Author
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Elson J. Shields and Antonio M. Testa
- Subjects
0106 biological sciences ,010602 entomology ,business.industry ,Insect Science ,Biological pest control ,Entomopathogenic nematode ,Biology ,business ,01 natural sciences ,Agronomy and Crop Science ,010606 plant biology & botany ,High humidity ,Biotechnology - Abstract
The wide spread use of biological control agents in commercial agriculture is frequently limited by the high cost of the biological control agents. We describe in this paper an entomopathogenic nematode (EPN) “in vivo” mass rearing method, not based on the White trap concept, which is both “low technology” and “low labor”, reducing the cost of producing large quantities of EPN IJ to the level conducive for use in an area-wide biocontrol program. Rearing temperature has a significant impact on the number of EPN IJ produced per host larvae and the IJ viability at any point in time. Emerged IJs remain within a non-aqueous, high humidity environment with improved oxygen access without extra steps or equipment. Depending on storage conditions, IJs remain viable for 7–14 d without extra labor. Our laboratory has used this rearing method to rear more than 100 billion IJ in the past 8 years to support an area wide biological control program.
- Published
- 2017
47. The response strategies of Colletotrichum gloeosporioides s.s. due to the stress caused by biological control agent Bacillus amyloliquefaciens deciphered by transcriptome analyses
- Author
-
Zhen-Yu Liu, Yan-Ping Ji, Yu-Kun Qi, De-Wei Li, Xiao-Qin Wu, Qing-Hai Wang, and Yong-Yun Qu
- Subjects
0106 biological sciences ,Genetics ,biology ,Bacillus amyloliquefaciens ,biology.organism_classification ,01 natural sciences ,Transcriptome ,010602 entomology ,Colletotrichum ,Insect Science ,Gene expression ,Efflux ,Signal transduction ,Agronomy and Crop Science ,Gene ,Pathogen ,010606 plant biology & botany - Abstract
Walnut is cultivated all over the world for its precious woody nut and edible oil. Walnut anthracnose caused by Colletotrichum spp. is a disastrous disease in the walnut plantation. In China, this disease is difficult to control. The efficacies of the traditional preventing and controlling measures are inadequate. It causes serious losses every year. In the interaction systems of ‘antagonistic organism-pathogen’, the response mechanisms of the pathogen to the stress of antagonistic organisms were largely unknown. To understand the response mechanisms of walnut anthracnose pathogen, Colletotrichum gloeosporioides sensu stricto (s.s.) TS-09R was treated with Bacillus amyloliquefaciens, and RNAseq gene expression analyses were performed. A total of 610 genes expressed differentially (DEGs). Among these genes, 387 genes were up-regulated and 223 genes were down-regulated. Gene ontology (GO) analysis showed that 409 DEGs involved in the categories of biological process, and cellular component. The KEGG pathway enrichment analysis showed that all up-regulated DEGs were enriched in amino acid metabolism, biosynthesis of other secondary metabolites, and xenobiotics biodegradation and metabolism. Further analyses indicated that C. gloeosporioides s.s. TS-09R up-expressed significantly some DEGs associated with cell membrane synthesis and, or maintaining stabilization, antioxidant and anti-stress to build the cell membrane, maintain the normal physiological function of cells. At the same time, it improved detoxification efficiency and reduced its sensitivity to the exogenous antimicrobial substance (EAS). It also improved the activity of the efflux pump translocating EAS out of the cells, reduced accumulation, and minimized injuries to cells. C. gloeosporioides s.s. TS-09R also up-expressed significantly genes associated with sporulation to promote spore production for survival in adversity. C. gloeosporioides s.s. TS-09R recruited numerous genes to respond to or resist the biocontrol of B. amyloliquefaciens. The response model was a holistic and complex network involving multiple genes and multiple signaling pathways. Additionally, the glutathione-S-transferases (GST) activities of C. gloeosporioides s.s. TS-09R, TS-09 cultured for 5 days and 9 days were calculated, and the GST activity had a similar change trend to the GST-related gene expression. The result indicated that the hypothetical response strategies were reliable. In this paper, we provided new insights into the onset of the interaction system of ‘C. gloeosporioides s.s. – B. amyloliquefaciens’. The results will contribute to exploring comprehensively the mechanism of B. amyloliquefaciens according to the response mechanisms of C. gloeosporioides s.s.
- Published
- 2020
48. Biocontrol of the cat flea, Ctenocephalides felis, by entomopathogenic nematodes and fungi
- Author
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Dana Ment, Michael Samish, Itamar Glazer, Adi Behar, Asael Rot, and Galina Gindin
- Subjects
Veterinary medicine ,Flea ,biology ,animal diseases ,Cat flea ,Felis ,fungi ,Biological pest control ,bacterial infections and mycoses ,biology.organism_classification ,Pulicidae ,Insect Science ,Heterorhabditis bacteriophora ,Agronomy and Crop Science ,Rhabditida ,Ctenocephalides - Abstract
The cat flea, Ctenocephalides felis (Bouche) (Siphonaptera: Pulicidae), is the most important ectoparasite of domestic pets. Its control is mainly based on chemical insecticides. In this study, the potential of fungi and nematodes to control this pest was evaluated. The various life stages of the cat flea were exposed to several variables: strains and species of entomopathogenic nematodes and fungi at different ambient temperatures and levels of relative humidity (RH), as well as in\on filter paper, sand or carpet as substrates. The nematode Steinernema feltiae (Nematoda: Steinernematidae) was most virulent against flea larvae, cocoons and adults, and the nematode Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) was highly effective against flea cocoons on all substrates evaluated. Overall, the nematodes were most effective at 28o C and 95% RH. The fungus Metarhizium robertsii 2575 (Bischoff) (Hypocreales: Clavicipitaceae), was highly virulent against adult fleas. Flea eggs were resistant to both nematodes and the fungus evaluated. The results indicate high potential for use of microbial control agents against cat fleas. While the fungus, M. robertsii, could be effective in killing adult fleas on infested vertebrates, the nematodes S. feltiae and H. bacteriophora could be successful in controlling pre-imaginal stages on the soil.
- Published
- 2020
49. Dissemination of Lathrolestes ensator (Ichneumonidae), a larval parasite of the European Apple Sawfly, Hoplocampa testudinea (Tenthredinidae), in Eastern North America
- Author
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Charles Vincent, Alan Eaton, Jacques Lasnier, and Margaret Appleby
- Subjects
0106 biological sciences ,biology ,Ecology ,Apple tree ,Parasitism ,Hymenoptera ,biology.organism_classification ,01 natural sciences ,010602 entomology ,Ichneumonidae ,Sawfly ,Horticulture ,Insect Science ,Hoplocampa testudinea ,PEST analysis ,Agronomy and Crop Science ,Tenthredinidae ,010606 plant biology & botany - Abstract
The larval parasite Lathrolestes ensator Brauns (Hymenoptera: Ichneumonidae) has only one known host, Hoplocampa testudinea Klug (Hymenoptera: Tenthredinidae), a pest that attacks only one host: the apple tree. A classical biological program conducted from 1994 to 2001 successfully led to the establishment of L. ensator in Frelighsburg, QC, Canada. This paper reports on work conducted from 2002 to 2015 to disseminate L. ensator in eastern North America. Each year, fruitlets showing secondary damage of H. testudinea were collected in source orchards of Frelighsburg. Random samples of these fruitlets were dissected to estimate % parasitized larvae: the remaining fruitlets were used for releases in apple orchards located in Quebec, Ontario, Nova Scotia and New Hampshire. Collection of fruitlets with secondary damage in participating orchards showed that L. ensator successfully established in Quebec in Henryville, Saint-Hilaire, Magog and St-Georges de Windsor, and in Ontario in Hilton. L. ensator is the only known natural enemy of H. testudinea in North America.
- Published
- 2016
50. Impact of macrocidins, produced by Phoma macrostoma, on carotenoid profiles of plants
- Author
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Karen L. Bailey, Michelle Hubbard, and Russell K. Hynes
- Subjects
chemistry.chemical_classification ,Phytoene desaturase ,food.ingredient ,food and beverages ,Dandelion ,Biology ,biology.organism_classification ,chemistry.chemical_compound ,food ,Phytoene ,chemistry ,Taraxacum officinale ,Insect Science ,Botany ,Thistle ,Cucurbita ,Agronomy and Crop Science ,Carotenoid ,Bioherbicide - Abstract
Phoma macrostoma (Montagne) is a bioherbicide that controls broadleaf weeds such as Canada thistle ( Cirsium arvense L. (Scop.)) and dandelion ( Taraxacum officinale Weber ex F.H. Wigg.), while leaving crop plants, such as wheat ( Triticum aestivum L.) and pumpkin ( Cucurbita L. spp), unharmed. The bioherbicidal activity of P. macrostoma is largely due to the production of phytotoxic secondary metabolites, macrocidins. While macrocidins produce photobleaching symptoms in susceptible plants, the mechanism(s) by which this occurs are not known. The hypothesis that macrocidins inhibit carotenoid biosynthesis was tested by comparing the carotenoid profiles and other physiological parameters of macrocidin-treated Canada thistle, dandelion, pumpkin and wheat with control plants and plants treated with the known carotenoid biosynthesis inhibitor, diflufenican. Only in susceptible plants, macrocidins induced photobleaching symptoms, lowered total chlorophyll content and reduced photosynthetic gas exchange while increasing the percentage of the carotenoid precursor phytoene. While diflufenican also led to chlorosis in dandelion and thistles, its impacts differed from those of macrocidins in that diflufenican-treated dandelion, thistle and pumpkin had increased total carotenoid and carotenoid precursor content compared to the control. Diflufenican-treated dandelion and thistle contained 88 ± 3% and 94 ± 2% phytoene, respectively. In contrast, macrocidins-treated dandelion and thistle (at the higher dose) contained 54 ± 12% and 80 ± 3% phytoene, respectively, while the controls contained only 4 ± 0.5% and 10 ± 1%. The β-carotene to lutein ratio in diflufenican-treated dandelion or thistles did not differ from that of the control, while this ratio was reduced in thistles treated with the higher dose of macrocidins. This paper provides the first proof that macrocidins impact the carotenoid biosynthesis by partially inhibiting the carotenoid biosynthetic enzyme phytoene desaturase (PDS) and at one or more other steps in carotenoid biogenesis.
- Published
- 2015
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