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Endophytic bacteria (EB) are ubiquitous in most plant species and they colonize plant tissues actively and systemically. Their colonization and persistence in the plant may be crucial to plant growth, yield and suppressing diseases. In this study, the long-term population dynamics of the two EB, namely Ochrobactrum spp. strain CB36/1 and Pantoea agglomerans strain CC37/2 in cucumber plants (Cucumis sativus L. cv. Gordion F1), were monitored. Also, the potential effects of these EB on plant growth, fruit quality, and yield, as well as the influences on Angular leaf spot disease of cucumber (ALS) and the yield under the disease pressure, were investigated. Plants were grown using the soilless cultivation technique in the greenhouse. Inoculation of the EB took place twice, and their population in plant tissues were monitored periodically for 62 days. Both EB isolates survived in plant organs until the end of the growing season, but over time, population densities dropped from 105 to 103 CFU g. plant?1 with the age of the plant. The EB applications had significant effects on fruit length, color and firmness. Total yield increased by 22% with CB36/1 and 21% with CC37/2 without disease pressure. Only CC37 / 2 significantly reduced the severity of ALS disease by 41% and increased yield by 22% compared to pathogen treatment alone. In this study, it was observed that the EB strain CC37/2 might contribute to reducing the chemical input and prevent the yield losses in soilless growing systems within the integrated agricultural concept. © 2021 Elsevier B.V., FA1103 Türkiye Bilimsel ve Teknolojik Araştirma Kurumu, TÜBITAK: TUBITAK-COST 111 O 505, The present study was sponsored by national grants from the Scientific and Technological Research Council of Turkey (TUBITAK-COST 111 O 505) and Ege University Science-Technology Research and Application Center (EBILTEM). The authors express their gratitude for the contribution of the participants in EU-COST Action FA1103., The present study was sponsored by national grants from the Scientific and Technological Research Council of Turkey ( TUBITAK-COST 111 O 505 ) and Ege University Science-Technology Research and Application Center ( EBILTEM ). The authors express their gratitude for the contribution of the participants in EU-COST Action FA1103.

Plant root secreted compounds alter the gene expression of associated microorganisms by acting as signal molecules that either stimulate or repel the interaction with beneficial or harmful species, respectively. However, it is still unclear whether two distinct groups of beneficial bacteria, non-plant-associated (soil) strains and plant-associated (endophytic) strains, respond uniformly or variably to the exposure with root exudates. Therefore, Bacillus mycoides, a potential biocontrol agent and plant growth-promoting bacterium, was isolated from the endosphere of potatoes and from soil of the same geographical region. Confocal fluorescence microscopy of plants inoculated with GFP-tagged B. mycoides strains showed that the endosphere isolate EC18 had a stronger plant colonization ability and competed more successfully for the colonization sites than the soil isolate SB8. To dissect these phenotypic differences, the genomes of the two strains were sequenced and the transcriptome response to potato root exudates was compared. The global transcriptome profiles evidenced that the endophytic isolate responded more pronounced than the soil-derived isolate and a higher number of significant differentially expressed genes were detected. Both isolates responded with the alteration of expression of an overlapping set of genes, which had previously been reported to be involved in plant-microbe interactions; including organic substance metabolism, oxidative reduction, and transmembrane transport. Notably, several genes were specifically upregulated in the endosphere isolate EC18, while being oppositely downregulated in the soil isolate SB8. These genes mainly encoded membrane proteins, transcriptional regulators or were involved in amino acid metabolism and biosynthesis. By contrast, several genes upregulated in the soil isolate SB8 and downregulated in the endosphere isolate EC18 were related to sugar transport, which might coincide with the different nutrient availability in the two environments. Altogether, the presented transcriptome profiles provide highly improved insights into the life strategies of plant-associated endophytes and soil isolates of B. mycoides.

Fusarium root rot is a major cryptogamic disease in olive trees caused by the soil-borne fungus Fusarium solani. Controlling this disease requires the extensive use of chemicals. However, using BCAs such as some Trichoderma strains may be an opportune alternative to fungicides in protecting olive plantations. A new isolate (Fso14) was isolated from young olive trees showing severe dieback symptoms. The objective of this work was to analyze the biocontrol behavior of a Tunisian strain of T. harzianum (Ths97) on olive trees against Fso14 by assessing both mycoparasitic activity (in planta and in vitro) and ability to locally modulate different gene-related defenses of the plant. Ths97 was found to inhibit Fso14 growth in vitro. Optical microscopic analysis at the confrontation zone between hyphae showed that Ths97 grew alongside Fso14 with numerous contact points suggesting parasitic activity. On olive trees, Ths97 developed a strong protective role against root infestation by Fso14, whether inoculated before or after the pathogenic agent. When inoculated alone, Fso14 and Ths97 did not modulate (or only slightly with inhibitions or inductions, respectively) the expression of genes involved in plant immunity (oxidative stress, phenylpropanoid pathway, PR-proteins and JA/Et-SA hormonal status). However, when Ths97 was inoculated in combination with Fso14, several defense-related genes were highly up-regulated, indicating probable primed-plant events. These promising results provided valuable information on using Ths97 as a beneficial agent to control fusarium root rot disease caused by F. solani in olive trees.

Until the 1990s, herbivory on aquatic vascular plants was considered to be of minor importance, and the predominant view was that freshwater and marine macrophytes did not take part in the food web: their primary fate was the detritivorous pathway. In the last 25 years, a substantial body of evidence has developed that shows that herbivory is an important factor in the ecology of vascular macrophytes across freshwater and marine habitats. Herbivores remove on average 40–48% of plant biomass in freshwater and marine ecosystems, which is typically 5–10 times greater than reported for terrestrial ecosystems. This may be explained by the lower C:N stoichiometry found in submerged plants. Herbivores affect plant abundance and species composition by grazing and bioturbation and therewith alter the functioning of aquatic ecosystems, including biogeochemical cycling, carbon stocks and primary production, transport of nutrients and propagules across ecosystem boundaries, habitat for other organisms and the level of shoreline protection by macrophyte beds. With ongoing global environmental change, herbivore impacts are predicted to increase. There are pressing needs to improve our management of undesirable herbivore impacts on macrophytes (e.g. leading to an ecosystem collapse), and the conflicts between people associated with the impacts of charismatic mega-herbivores. While simultaneously, the long-term future of maintaining both viable herbivore populations and plant beds should be addressed, as both belong in complete ecosystems and have co-evolved in these long before the increasing influence of man. Better integration of the freshwater, marine, and terrestrial herbivory literatures would greatly benefit future research efforts., JFP acknowledges financial support from the Welsh Government and Higher Education Funding Council for Wales through the Sêr Cymru National Research Network for Low Carbon, Energy and Environment.

Until the 1990s, herbivory on aquatic vascular plants was considered to be of minor importance, and the predominant view was that freshwater and marine macrophytes did not take part in the food web: their primary fate was the detritivorous pathway. In the last 25 years, a substantial body of evidence has developed that shows that herbivory is an important factor in the ecology of vascular macrophytes across freshwater and marine habitats. Herbivores remove on average 40-48% of plant biomass in freshwater and marine ecosystems, which is typically 5-10 times greater than reported for terrestrial ecosystems. This may be explained by the lower C:N stoichiometry found in submerged plants. Herbivores affect plant abundance and species composition by grazing and bioturbation and therewith alter the functioning of aquatic ecosystems, including biogeochemical cycling, carbon stocks and primary production, transport of nutrients and propagules across ecosystem boundaries, habitat for other organisms and the level of shoreline protection by macrophyte beds.With ongoing global environmental change, herbivore impacts are predicted to increase. There are pressing needs to improve our management of undesirable herbivore impacts on macrophytes (e.g. leading to an ecosystem collapse), and the conflicts between people associated with the impacts of charismatic mega-herbivores. While simultaneously, the long-term future of maintaining both viable herbivore populations and plant beds should be addressed, as both belong in complete ecosystems and have co-evolved in these long before the increasing influence of man. Better integration of the freshwater, marine, and terrestrial herbivory literatures would greatly benefit future research efforts. (C) 2016 Elsevier B.V. All rights reserved.

The entomopathogenic fungus Beauveria bassiana is able to colonize and establish a symbiotic relationship with plants as an endophyte, naturally as well as through artificial inoculation. This study aims at implementing a reliable and efficient method to establish endophytic B. bassiana in maize plants. The level of the endophytic establishment was evaluated and the survival and fecundity of the English grain aphid (Sitobion avenae) was investigated. Eight-days-old maize plants were sprayed with a fungal spore suspension, while control plants were treated only with a Tween solution. Two weeks after inoculation, seven clip cages per plant, each containing an adult aphid, were attached to different leaves and left for seven days. All inoculated plants contained endophytic B. bassiana as confirmed by plating surface disinfected leaf pieces on selective plates. None of the control plants showed growth of B. bassiana. The highest colonization levels were 61% in older inoculated leaves and 19% in younger non-inoculated leaves. The survival of S. avenae on inoculated plants was reduced up to 49% as compared to control plants. Dead aphids did not show any signs of mycosis. The number of nymphs produced by a single aphid was reduced up to 70% and 74% on inoculated and non-inoculated leaves, respectively. Presence of endophytic B. bassiana in non-inoculated younger leaves implies the movement of the endophyte inside plants. The negative effect on aphid fecundity appears to be systemic as implied by the almost equal reduction of mean numbers of nymphs produced on older and younger leaves on the inoculated plants, irrespective of the level of colonization by endophytic B. bassiana.

Beneficial Pseudomonas spp. produce an array of antimicrobial secondary metabolites such as cyclic lipopeptides (CLPs). We investigated the capacity of CLP-producing Pseudomonas strains and their crude CLP extracts to control rice blast caused by Magnaporthe oryzae, both in a direct manner and via induced systemic resistance (ISR). In planta biocontrol assays showed that lokisin-, white line inducing principle (WLIP)-, entolysin- and N3-producing strains successfully induced resistance to M. oryzae VT5M1. Furthermore, crude extracts of lokisin, WLIP and entolysin gave similar ISR results when tested in planta. In contrast, a xantholysin-producing strain and crude extracts of N3, xantholysin and orfamide did not induce resistance against the rice blast disease. The role of WLIP in triggering ISR was further confirmed by using WLIP-deficient mutants. The severity of rice blast disease was significantly reduced when M. oryzae spores were pre-treated with crude extracts of N3, lokisin, WLIP, entolysin or orfamide prior to inoculation. In vitro microscopic assays further revealed the capacity of crude N3, lokisin, WLIP, entolysin, xantholysin and orfamide to significantly inhibit appressoria formation by M. oryzae. In addition, the lokisin and WLIP biosynthetic gene clusters in the producing strains are described. In short, our study demonstrates the biological activity of structurally diverse CLPs in the control of the rice blast disease caused by M. oryzae. Furthermore, we provide insight into the non-ribosomal peptide synthetase genes encoding the WLIP and lokisin biosynthetic machineries. ispartof: FRONTIERS IN PLANT SCIENCE vol:10 ispartof: location:Switzerland status: published

Globally, Anastatus species (Hymenoptera: Eupelmidae) are associated with the invasive agricultural pest Halyomorpha halys (Stal) (Hemiptera: Pentatomidae). In Europe, the polyphagous Anastatus bifasciatus (Geoffroy) is the most prevalent native egg parasitoid on H. halys eggs and is currently being tested as a candidate for augmentative biological control. Anastatus bifasciatus frequently displays behavior without oviposition, and induces additional host mortality through oviposition damage and host feeding that is not measured with offspring emergence. This exacerbates accurate assessment of parasitism and host impact, which is crucial for efficacy evaluation as well as for pre- and post-release risk assessment. To address this, a general Anastatus primer set amplifying a 318-bp fragment within the barcoding region of the cytochrome oxidase I (COI) gene was developed. When challenged with DNA of three Anastatus species -A. bifasciatus, Anastatus japonicus Ashmead, and Anastatus sp.-, five scelionid parasitoid species that might be encountered in the same host environments and 11 pentatomid host species, only Anastatus DNA was successfully amplified. When applied to eggs of the target host, H. halys, and an exemplary non-target host, Dendrolimus pini L. (Lepidoptera: Lasiocampidae), subjected to host feeding, no Anastatus amplicons were produced. Eggs of the two host species containing A. bifasciatus parasitoid stages, from 1-h-old eggs to pupae, and emerged eggs yielded Anastatus fragments. Confirmation of parasitoid presence with dissections and subsequent PCRs with the developed primer pair resulted in 95% success for 1-h-old parasitoid eggs. For both host species, field-exposed sentinel emerged eggs stored dry for 6 months, 100% of the specimens produced Anastatus amplicons. This DNA-based screening method can be used in combination with conventional methods to better interpret host-parasitoid and parasitoid-parasitoid interactions. It will help address ecological questions related to an environmentally friendly approach for the control of H. halys in invaded areas.

In this study, molecular (ribosomal sequence data), morphological and cross-hybridization properties were used to identify a newSteinernemasp. from Florida, USA. Molecular and morphological data provided evidence for placing the novel species into Clade V, or the ‘glaseri-group’ ofSteinernemaspp. Within this clade, analysis of sequence data of the rDNA genes, 28S and internal transcribed spacer (ITS), depicted the novel species as a distinctive entity and closely related toS. glaseriandS. cubanum.Additionally, cross-hybridization assays showed that the new species is unable to interbreed with either of the latter two species, reinforcing its uniqueness from a biological species concept standpoint. Key morphological diagnostic characters forS. khuongin. sp. include the mean morphometric features of the third-stage infective juveniles: total body length (average: 1066 μm), tail length (average: 65 μm), location of the excretory pore (average: 80.5 μm) and the values ofc(average: 16.4),D% (average: 60.5),E% (average: 126) andH% (average: 46.6). Additionally, males can be differentiated fromS. glaseriandS. cubanumby the values of several ratios:D% (average: 68),E% (average: 323) and SW% (average: 120). The natural distribution of this species in Florida encompasses both natural areas and citrus groves, primarily in shallow groundwater ecoregions designated as ‘flatwoods’. The morphological, molecular, phylogenetic and ecological data associated with this nematode support its identity as a new species in theS. glaseri-group.

In hymenopterans, males are normally haploid (1n) and females diploid (2n), but individuals with divergent ploidy levels are frequently found. In species with ‘complementary sex determination’ (CSD), increasing numbers of diploid males that are often infertile or unviable arise from inbreeding, presenting a major impediment to biocontrol breeding. Non‐CSD species, which are common in some parasitoid wasp taxa, do not produce polyploids through inbreeding. Nevertheless, polyploidy also occurs in non‐CSD Hymenoptera. As a first survey on the impacts of inbreeding and polyploidy of non‐CSD species, we investigate life‐history traits of a long‐term laboratory line of the parasitoid Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) (‘Whiting polyploid line’) in which polyploids of both sexes (diploid males, triploid females) are viable and fertile. Diploid males produce diploid sperm and virgin triploid females produce haploid and diploid eggs. We found that diploid males did not differ from haploid males with respect to body size, progeny size, mate competition, or lifespan. When diploid males were mated to many females (without accounting for mating order), the females produced a relatively high proportion of male offspring, possibly indicating that these males produce less sperm and/or have reduced sperm functionality. In triploid females, parasitization rate and fecundity were reduced and body size was slightly increased, but there was no effect on lifespan. After one generation of outbreeding, lifespan as well as parasitization rate were increased, and a body size difference was no longer apparent. This suggests that outbreeding has an effect on traits observed in an inbred polyploidy background. Overall, these results indicate some phenotypic detriments of non‐CSD polyploids that must be taken into account in breeding.

Temperature influences biological processes of ectotherms including ecological interactions, but interaction strengths may depend on species-specific traits. Furthermore, ectotherms acclimate to prevailing thermal conditions by adjusting physiological parameters, which often implies costs to other fitness-related parameters. Both predators and prey may therefore pay thermal acclimation costs following exposure to suboptimal temperatures. However, these costs may be asymmetrical between predator and prey, and between the predator and different species of concurrent prey. We investigated whether thermal pre-exposure affected subsequent kill rate and predator fitness when foraging on prey that differ in ease of capture, and whether changes were primarily caused by predator or by prey pre-exposure effects. Specifically, we were interested in whether there were interactions between predator pre-exposed temperature and specific prey. Using the mesostigmatid mite Gaeolaelaps aculeifer as a generalist predator and the collembolans Folsomia candida and Protaphorura fimata as prey, we measured the impact of present temperature, predator pre-exposure temperature, prey pre-exposure temperature (all 10 or 20°C), prey species, and all interactions on prey numbers killed, predator eggs produced, and exploitation of killed prey in a full factorial design. Mites killed P. fimata in equal numbers independent of the presence of F. candida, but killed F. candida when P. fimata was absent. Mite kill rate and reproduction were significantly affected by mite pre-exposure temperature and test temperature, but not by prey pre-exposure temperature. Significantly more of the slower prey was killed than of the quicker prey. Importantly, we found significant synergistic negative interaction effects between predator cold pre-exposure and hunting prey of higher agility on predator kill rate and reproduction. Our findings show that the negative effects of cold and cold pre-exposure on kill rate and reproduction may be more severe when predators forage on quick prey. The study implies that predator cold exposure has consequences for specific prey survival following cold due to altered predation pressures, which in nature should influence the specific prey population dynamics and apparent competition outcomes. The findings exemplify how not only current but also preceding conditions affect ecological interactions, and that effect strength depends on the species involved.

International audience; Cocoyam (Xanthosoma sagittifolium (L.)), an important tuber crop in the tropics, is severely affected by the cocoyam root rot disease (CRRD) caused by Pythium myriotylum. The white cocoyam genotype is very susceptible while the red cocoyam has some field tolerance to CRRD. Fluorescent Pseudomonas isolates obtained from the rhizosphere of healthy red and white cocoyams from three different fields in Cameroon were taxonomically characterized. The cocoyam rhizosphere was enriched with P. fluorescens complex and P. putida isolates independent of the plant genotype. LC–MS and NMR analyses revealed that 50% of the Pseudomonas isolates produced cyclic lipopeptides (CLPs) including entolysin, lokisin, WLIP, putisolvin and xantholysin together with eight novel CLPs. In general, CLP types were linked to specific taxonomic groups within the fluorescent pseudomonads. Representative CLP‐producing bacteria showed effective control against CRRD while purified CLPs caused hyphal branching or hyphal leakage in P. myriotylum. The structure of cocoyamide A, a CLP which is predominantly produced by P. koreensis group isolates within the P. fluorescens complex is described. Compared with the white cocoyam, the red cocoyam rhizosphere appeared to support a more diverse CLP spectrum. It remains to be investigated whether this contributes to the field tolerance displayed by the red cocoyam.

Artificial sugar solutions can be used to disrupt the mutualism between aphids and ants. This provides natural enemies with increased access to aphid populations, thus enhancing biocontrol of hemipteran pests. However, research suggests that artificial solutions should be tailored to specific species in order to maximize the desired result. In this study, we test the effect of an alkaloid, caffeine, and a non-protein amino acid, γ-aminobutyric acid (GABA), on preference for sucrose solutions in two ant species, Lasius niger and Oecophylla smaragdina. These secondary metabolites have been shown to have attractive capabilities in other species of insects, who favor nectars from plants containing these compounds. In our first experiment, both species significantly preferred solutions containing GABA over sucrose-only controls, albeit L. niger favored higher concentrations of the amino acid. Caffeine did not significantly increase preference for sugar solutions in either of the tested species, and ants significantly dispreferred the highest concentration of caffeine offered. When the two metabolites were tested simultaneously against sucrose only, L. niger fed equally from all solutions, while O. smaragdina dispreferred caffeine. Thus, while GABA seems to be a promising ant attractant, caffeine is not an adequate choice, at least at the concentrations tested in this experiment.

Generalist predators potentially have access to a wide array of prey, but it is little studied how experience with specific prey affects preference for this prey. In particular, it is unknown how experience with pest prey affects predator foraging decisions in cases where the pest is nutritious but protected by a repelling, potentially deadly defence. We investigated preference of the soil predatory mite Gaeolaelaps aculeifer Canestrini for the risky pest springtail Protaphorura fimata Gisin relative to the safe non-pest springtail Folsomia candida Willem. Egg production under foraging on live or dead individuals of either prey showed that the two species had equal nutritional quality for G. aculeifer, but indicated that live F. candida were more difficult to catch than live P. fimata. Importantly, some G. aculeifer were killed by P. fimata defence secretions, demonstrating that live P. fimata are risky prey. Preference for P. fimata was generally high when mites were given a choice between a live individual of either prey, but this preference was reduced following exposure to live individuals of P. fimata. Furthermore, fewer G. aculeifer killed a prey and time until kill was longer after experience with live P. fimata. These findings indicate that live P. fimata induced a partial aversion on G. aculeifer during exposure. Our study shows that generalist predators can reduce their preference for risky prey following exposure. This indicates that generalist predators used in biological control against risky prey are most efficient against this prey if not exposed to it prior to release.

In this review, we examine how the principles of ecostacking could be used to manage the pollen beetle Brassicogethes aeneus in oilseed crucifer crops. We further describe hindrances preventing progress of keeping the pest under full biological control across Europe, and for other similar pest management situations. Ecological processes at different levels need to be considered and understood. The beneficial functions, which the various ecosystem service providers offer, need to be combined and exploited in an additive or synergistic manner, i.e., ecostacked. Levels to consider include landscape and off-crop habitats (e.g., field margins) and their effects on pest management in the rapeseed crop; and possibilities to generate the key ecosystem services within the crop itself; for example, by vegetation management (e.g., undersowing, variety mixtures, companion and trap crops), soil management (biotic and abiotic; fostering and steering soil microbial communities to benefit biocontrol), and crop management, including crop protection treatments and their impacts on ecosystem service provision. All these processes affect the populations of the pollen beetle. Abundant information exists about most of the key processes important in this context. Utilizing this knowledge and stacking the various beneficial ecosystem service functions into a comprehensive management strategy for the pollen beetle, has not been attempted nor described. After illustrating the potential of ecostacking in solving crop protection problems, as it is apparent in the case of the pollen beetle, we analyze a situation where our approach was lost in translation. The European Union Horizon 2020 program chose to support our vision of ecostacking with a 10million euro grant. Administrative decisions by the coordinating university (not to accept to host the grant), and subsequent failure of the European Commission and its Research Executive Agency to demonstrate leadership on issues of research policy, integrity, and ethics in the handling of the project, resulted in a shift of emphasis away from solutions based on integrative biocontrol.

[Departement_IRSTEA]Ecotechnologies [ADD1_IRSTEA]Dynamique et fonctionnement des écosystèmesSous presse; Green-veining policies aiming at restoring biodiversity in agricultural landscapes mainly focus on the connectivity of semi-natural habitats. However, little is known about the potential role of crop connectivity for the biodiversity using cropped habitats. The goal of the present study was to investigate the effects of habitat connectivity related to annual crops vs. semi-natural habitats (woody elements) on insect biodiversity (carabid beetles) in agricultural landscapes, considering contrasted groups of species in terms of habitat preference and dispersal ability. Results showed that the spatial configuration and connectivity of annual crops in the landscape (here, up to 500 m) can contribute to increased abundance of some groups of carabid species. Spatial continuities between spring and winter crops (in 250 m radius circles) had beneficial effects on farmland species with low mobility (brachypterous) in maize crops, possibly reflecting resource complementation processes. The connectivity of annual crops also had positive effects on abundances of dimorphic farmland species in maize crops and of forest species in woodland, but at contrasted spatial scales (in 250 m vs. 50 m radius circles respectively). The present study also revealed antagonistic effects of landscape patterns related to both crops (edge length between winter and spring crops) and semi-natural habitats (percent cover of woodland) on farmland and forest species, highlighting critical issues regarding the conservation of such contrasted ecological species groups in agricultural landscapes.

Agricultural practices often involve tank-mixing and co-application of insecticides with fungicides to control crop pests. However, natural methods relying on biological control agents such as hymenopteran parasitoids have been shown to be highly effective in suppressing crop pest populations. The current body of insecticide risk assessment data accounting for fungicide co-application is very small, the present study being the first to examine this in a parasitoid wasp. Through low-dose exposure to dry residues of the neonicotinoid insecticide thiacloprid, we examined its mortal and knockdown effect on Aphelinus abdominalis when co-applied with increasing doses of the fungicide tebuconazole. Both of these acute effects of thiacloprid were synergised (toxicity increased to a greater-than-additive effect) by tebuconazole, resulting in significant mortality from low-dose co-applications of tebuconazole, and significant knockdown even without co-applied tebuconazole, the effect increasing as tebuconazole concentration increased. We show the highly toxic effect that a low dose of thiacloprid imposes on A. abdominalis populations, and a synergistic toxicity when co-applied with low doses of tebuconazole. Our work suggests a need for updating pesticide risk assessment methods, accounting for pesticide mixtures, in order to make these risk assessments more field relevant.

Fusarium graminearum can cause Giberella Ear Rot (GER) and seedling blight in maize, resulting in major yield losses. Besides GER, the infected grains are consequently contaminated with multiple mycotoxins of F. graminearum. Zearalenone and trichothecenes, such as deoxynivalenol and its acetylated forms, are among the major mycotoxins associated with F. graminearum infection in maize. In the current work, we explored the effect of the endophytic fungal genera of Epicoccum and Sordaria, to control F. graminearum infection in comparative trials with Piriformospora spp., an elusive endophytic genus. Furthermore, we investigated the effect of these endophytes on zearalenone, deoxynivalenol, and 15-acetyldeoxynivalenol levels using in vitro and in planta assays. As plants are endowed with several detoxification mechanisms comprising e.g., glucosylation of trichothecenes, the effect of the isolated fungal endophytes on the deoxynivalenol-3-glucoside level was also assessed. In general, results showed a considerable variability in the antifungal activity, both among species and among isolates within one species. Additionally, the effect on mycotoxin levels was variable, and not necessarily related to the antifungal activity except for zearalenone levels which were consistently reduced by the endophytes. These results highlight the great potential of certain endophytic fungal strains as new biocontrol agents in agricultural science.

Plant microbiome plays an important role in maintaining the host fitness. Despite a significant progress in our understanding of the plant microbiome achieved in the recent years, very little is known about the effect of plant pathogens on composition of microbial communities associated with trees. In this study, we analysed the mycobiome of different anatomic parts of asymptomatic and symptomatic Norway spruce trees naturally infected by Heterobasidion spp. We also investigated the primary impact of the disease on the fungal communities, which are associated with Norway spruce trees. Our results demonstrate that the structure of fungal communities residing in the wood differed significantly among symptomatic and asymptomatic Heterobasidion-infected trees. However, no significant differences were found in the other anatomic regions of the trees. The results also show that not only each of individual tree tissues (wood, bark, needles and roots) harbours a unique fungal community, but also that symptomatic trees were more susceptible to co-infection by other wood-degrading fungi compared to the asymptomatic ones.

Powdery mildew (Blumeria graminis f.sp. tritici, f.sp. hordei, f.sp. avenae) is an important disease in cereal crops causing significant yield reductions, if not effectively controlled. The biofungicide Bacillus amyloliquefaciens (former subtilis) strain QST 713 suspension concentrate (Serenade®ASO) was investigated for its potential as a control agent against powdery mildew in winter wheat, spring barley, oats and triticale. Serenade®ASO reduced the severity of powdery mildew, providing moderate control in the range of 20–65%. The efficacy was highest at the earlier assessments and less pronounced at later assessments. With a few exceptions, no clear dose-response was seen between using 1, 2, 4, 6 or 8 L/ha Serenade®ASO applied four times at 8–10-day intervals. The efficacy was more variable compared with chemical references. Yield responses were positive following treatments. However, the yield increase by Serenade®ASO was insignificant and significantly inferior to that of prothioconazole. In a few cases, the use of Serenade®ASO in combination with the adjuvant Silwet®Gold improved the efficacy, but the results were inconsistent. The preventive and curative application of Serenade®ASO was tested at three dose rates in an artificially inoculated wheat and barley greenhouse pot trial. These trials confirmed the lack of a clear dose-response but confirmed that timing has a major impact on control, with the best control obtained when application took place on the day of inoculation in wheat and 0–2 days after inoculation in barley. This study revealed that powdery mildew challenges Serenade®ASO as a stand-alone control measure. The results show that further research is needed for the promotion of biofungicides as part of an integrated disease management approach in cereal diseases.

The relative importance of bottom‐up versus top‐down control of population dynamics has been the focus of much debate. In infectious disease biology, research is typically focused on the bottom‐up process of host resistance, wherein the direction of control flows from the lower to the higher trophic level to impact on pathogen population size and epidemiology. However, the importance of top‐down control by a pathogen's natural enemies has been mostly overlooked.Here, we explore the effects of, and interaction between, host genotype (i.e., genetic susceptibility to pathogen infection) and infection by a hyperparasitic fungus, Ampelomyces spp., on the establishment and early epidemic growth and transmission of a powdery mildew plant pathogen (Podosphaera plantaginis). We used a semi‐natural field experiment to contrast the impacts of hyperparasite infection, host‐plant resistance and spatial structure to reveal the key factors that determine pathogen spread. We then used a laboratory‐based inoculation approach to test whether the field experiment results hold across multiple pathogen–host genetic combinations and to explore hyperparasite effects on the pathogen's later life‐history stages.We found that hyperparasite infection had a negligible effect on within‐host infection development and between‐host spread of the pathogen during the onset of epidemics. In contrast, host‐plant resistance was the major determinant of whether plants became infected, and host genotype and proximity to an infection source determined infection severity.Our laboratory study showed that, while the interaction between host and pathogen genotypes was the key determinant of infection outcome, hyperparasitism did, on average, reduce the severity of infection. Moreover, hyperparasite infection negatively influenced the production of the pathogen's overwintering structures. Synthesis and applications. Our results suggest that bottom‐up host resistance affects pathogen spread, but top‐down control of powdery mildew pathogens is likely more effective against later life‐history stages. Further, while hyperparasitism in this system can reduce early pathogen growth under stable laboratory conditions, this effect is not detectable in a semi‐natural environment. Considering the effects of hyperparasites at multiple points in pathogen's life history will be important when considering hyperparasite‐derived biocontrol measures in other natural and agricultural systems., Our results suggest that bottom‐up host resistance affects pathogen spread, but top‐down control of powdery mildew pathogens is likely more effective against later life‐history stages. Further, while hyperparasitism in this system can reduce early pathogen growth under stable laboratory conditions, this effect is not detectable in a semi‐natural environment. Considering the effects of hyperparasites at multiple points in pathogen's life history will be important when considering hyperparasite‐derived biocontrol measures in other natural and agricultural systems.

Peat based growing media are not ecologically sustainable and often fail to support biological control. Miscanthus straw was (1) tested to partially replace peat; and (2) pre-colonized with a Trichoderma strain to increase the biological control capacity of the growing media. In two strawberry pot trials (denoted as experiment I & II), extruded and non-extruded miscanthus straw, with or without pre-colonization with T. harzianum T22, was used to partially (20% v/v) replace peat. We tested the performance of each mixture by monitoring strawberry plant development, nutrient content in the leaves and growing media, sensitivity of the fruit to the fungal pathogen Botrytis cinerea, rhizosphere community and strawberry defense responses. N immobilization by miscanthus straw reduced strawberry growth and yield in experiment II but not in I. The pre-colonization of the straw with Trichoderma increased the post-harvest disease suppressiveness against B. cinerea and changed the rhizosphere fungal microbiome in both experiments. In addition, defense-related genes were induced in experiment II. The use of miscanthus straw in growing media will reduce the demand for peat and close resource loops. Successful pre-colonization of this straw with biological control fungi will optimize crop cultivation, requiring fewer pesticide applications, which will benefit the environment and human health.

Ectotherms respond to their thermal environments by physiological acclimation, which increases tolerance to thermal extremes and may increase field performance. However, acclimation often has costs, and increased performance in some traits may be associated with reduced performance in other traits due to trade-offs. We investigated effects of thermal acclimation on predation, reproduction, starvation tolerance, and locomotor activity in the predatory mite Gaeolaelaps aculeifer Canestrini at 10, 15, and 20 degrees C after seven days of exposure to either of the same three temperatures, following rearing at 20 degrees C. To test for effects of cold acclimation on cold tolerance, another set of mites were acclimated at each of the three temperatures over four days including an additional group at 5 degrees C, and survival was assayed following a 24 h exposure to -2 degrees C. Our results showed highest cold-and starvation tolerance but lowest predation and reproduction across test temperatures in mites acclimated to 10 degrees C. These relationships were intermediate after 15 degrees C acclimation and opposite after 20 degrees C acclimation. Locomotor activity was unaffected by acclimation temperature. Since predation and reproduction of G. aculeifer are lowered across temperatures after cold acclimation, we recommend keeping cultures at 20 degrees C without cold exposure until release in the field when used against heavy pest infestations. However, if using G. aculeifer to keep small infestations minimized, we recommend using cold acclimated mites that better tolerate low temperature and low prey availability. Such thermal and metabolic robustness could be advantageous if predatory control agents are introduced in agroecosystems in early spring to prevent establishment of pest populations.

The Asian weaver ant Oecophylla smaragdina is of importance to Southeast Asian livelihoods as a source of human food and animal feed and as biological control agent in tree crops including mango and citrus. The introduction of weaver ants in plantations requires the inclusion of the reproductive queen. We report on locating the gravid queen in a mature O. smaragdina colony in Laos. The queen tree could be identified by considering tree height and number of nests in the tree: no tree was taller and housed more nests than the queen tree. The queen nest was a small nest, located near the tree top and near the trunk, and with more workers patrolling its exterior than at other small nests in the queen tree. The queen nest can be highly inconspicuous in dense tree crowns. Queen nest identification was ascertained by tapping and shaking nests, supporting branches, or entire trees, which elicits queen evacuation with retinue.

Pink ear rot of maize caused by Fusarium verticillioides, Fusariumproliferatum and Fusariumgraminearum can lead to severe yield losses and contamination of grain with a range of mycotoxins. Maize stalks colonized by Fusarium spp. are the main primary inoculum source for Fusarium incited epidemics in maize or other susceptible crops grown in rotation. The colonization of individual maize stalks originating from fields in The Netherlands, Italy and Nigeria by Fusarium spp. was quantified using specific TaqMan-PCR assays. Highest values were found for F. graminearum and Fusariumavenaceum in Dutch samples, for F. graminearum and FUM producing species (F. verticillioides and F. proliferatum) in Italian samples and FUM producing Fusarium spp. in Nigerian samples. The increase in Fusarium spp. colonization under field conditions during a period of 3-6 months after harvest of the maize crops varied considerably between individual stalks. The fungal and bacterial diversity was analyzed for sub-sets of stalks with high versus low increase of Fusarium colonization. Bacterial taxonomic groups such as Bacillus, Curtobacterium, Erwinia, Flavobacterium, Novosphingobium, Pantoea, Sphingomonas, Rahnella and Staphylococcus and fungal taxonomic groups such as Acremomium sp., Cryptococcus flavescens, Cryptococcus zeae, Leptosphaeria sp. and Microdochium bolleyi were more abundant in the stalks with lower increase in pathogen colonization. Such fungal and bacterial groups associated with 'suppressive stalks' may be antagonistic to Fusarium spp. and a source of candidate strains for the selection of new biological control agents.

There is limited understanding about how insect movement patterns are influenced by landscape features, and how landscapes can be managed to suppress pest phytophage populations in crops. Theory suggests that the relative timing of pest and natural enemy arrival in crops may influence pest suppression. However, there is a lack of data to substantiate this claim. We investigate the movement patterns of insects from native vegetation (NV) and discuss the implications of these patterns for pest control services. Using bi-directional interception traps we quantified the number of insects crossing an NV/crop ecotone relative to a control crop/crop interface in two agricultural regions early in the growing season. We used these data to infer patterns of movement and net flux. At the community-level, insect movement patterns were influenced by ecotone in two out of three years by region combinations. At the functional-group level, pests and parasitoids showed similar movement patterns from NV very soon after crop emergence. However, movement across the control interface increased towards the end of the early-season sampling period. Predators consistently moved more often from NV into crops than vice versa, even after crop emergence. Not all species showed a significant response to ecotone, however when a response was detected, these species showed similar patterns between the two regions. Our results highlight the importance of NV for the recruitment of natural enemies for early season crop immigration that may be potentially important for pest suppression. However, NV was also associated with crop immigration by some pest species. Hence, NV offers both opportunities and risks for pest management. The development of targeted NV management may reduce the risk of crop immigration by pests, but not of natural enemies.

In Pseudomonas species, production of secondary metabolites and exoenzymes is regulated by the GacS/GacA two-component regulatory system. In P. fluorescens SBW25, mutations in the Gac-system cause major transcriptional changes and abolished production of the lipopeptide viscosin and of an exoprotease. In contrast to many other Pseudomonas species and strains, inactivation of the Gac-system in strain SBW25 significantly enhanced its antimicrobial activities against oomycete, fungal and bacterial pathogens. Here, random plasposon mutagenesis of the gacS mutant led to the identification of seven mutants with reduced or loss of antimicrobial activity. In four mutants, the plasposon insertion was located in genes of the pyrroloquinoline quinone (PQQ) biosynthesis pathway. Genetic complementation, ectopic expression, activity bioassays and RP-HPLC analyses revealed that a gacS mutation in SBW25 leads to enhanced expression of pqq genes, resulting in an increase in gluconic and 2-ketogluconic acid production, which in turn acidified the extracellular medium to levels that inhibit growth of other microorganisms. We also showed that PQQ-mediated acidification comes with a growth penalty for the gacS mutant in the stationary phase. In conclusion, PQQ-mediated acidification compensates for the loss of several antimicrobial traits in P. fluorescens SBW25 and may help gac mutants to withstand competitors.

There is considerable evidence that both plant diversity and plant identity can influence the level of predation and predator abundance aboveground. However, how the level of predation in the soil and the abundance of predatory soil fauna are related to plant diversity and identity remains largely unknown. In a biodiversity field experiment, we examined the effects of plant diversity and identity on the infectivity of entomopathogenic nematodes (EPNs, Heterorhabditis and Steinernema spp.), which prey on soil arthropods, and abundance of carnivorous non-EPNs, which are predators of other nematode groups. To obtain a comprehensive view of the potential prey/food availability, we also quantified the abundance of soil insects and nonpredatory nematodes and the root biomass in the experimental plots. We used structural equation modeling (SEM) to investigate possible pathways by which plant diversity and identity may affect EPN infectivity and the abundance of carnivorous non-EPNs. Heterorhabditis spp. infectivity and the abundance of carnivorous non-EPNs were not directly related to plant diversity or the proportion of legumes, grasses and forbs in the plant community. However, Steinernema spp. infectivity was higher in monocultures of Festuca rubra and Trifolium pratense than in monocultures of the other six plant species. SEM revealed that legumes positively affected Steinernema infectivity, whereas plant diversity indirectly affected the infectivity of Heterorhabditis EPNs via effects on the abundance of soil insects. The abundance of prey (soil insects and root-feeding, bacterivorous, and fungivorous nematodes) increased with higher plant diversity. The abundance of prey nematodes was also positively affected by legumes. These plant community effects could not be explained by changes in root biomass. Our results show that plant diversity and identity effects on belowground biota (particularly soil nematode community) can differ between organisms that belong to the same feeding guild and that generalizations about plant diversity effects on soil organisms should be made with great caution.

Plant-associated bacteria are known for their high functional trait diversity, from which many are likely to play a role in primary and secondary succession, facilitating plant establishment in suboptimal soils conditions. Here we used an undisturbed salt marsh chronosequence that represents over 100 years of soil development to assess how the functional traits of plant associated bacteria respond to soil type, plant species and plant compartment. We isolated and characterized 808 bacterial colonies from the rhizosphere soil and root endosphere of two salt marsh plants, Limonium vulgare and Artemisia maritima, along the chronosequence. From these, a set of 59 strains (with unique BOX-PCR patterns, 16S rRNA sequence and unique to one of the treatments) were further screened for their plant growth promoting traits (siderophore production, IAA production, exoprotease production and biofilm formation), traits associated with bacterial fitness (antibiotic and abiotic stress resistance - pH, osmotic and oxidative stress, and salinity) and metabolic potential. An overall view of functional diversity (multivariate analysis) indicated that the distributional pattern of bacterial functional traits was driven by soil type. Samples from the late succession (Stage 105 year) showed the most restricted distribution, harboring strains with relatively low functionalities, whereas the isolates from intermediate stage (35 year) showed a broad functional profiles. However, strains with high trait performance were largely from stage 65 year. Grouping the traits according to category revealed that the functionality of plant endophytes did not vary along the succession, thus being driven by plant rather than soil type. In opposition, the functionality of rhizosphere isolates responded strongly to variations in soil type as observed for antibiotic resistance (P = 0.014). Specifically, certain Pseudomonas sp. and Serratia sp. strains revealed high resistance against abiotic stress and antibiotics and produce more siderophores, confirming the high plant-growth promoting activity of these two genera. Overall, this study contributes to a better understanding of the functional diversity and adaptation of the microbiome at typical salt marsh plant species across soil types. Specifically, soil type was influential only in the rhizosphere but not on the endosphere, indicating a strong plant-driven effect on the functionality of endophytes.

Tracking of fluorescent protein (FP)-labelled rhizobacteria is a key prerequisite to gain insights into plant-bacteria interaction mechanisms. However, the performance of FPs mostly has to be optimized for the bacterial host and for the environment of intended application. We report on the construction of mutational libraries of the superfolder green fluorescent protein sfGFP and the red fluorescent protein mKate2 in the bacterium B. mycoides, which next to its potential as plant-biocontrol agent occasionally enters an endophytic lifestyle. By fluorescence-activated cell sorting and comparison of signal intensities at the colony and single-cell level, the variants sfGFP(SPS6) and mKate (KPS12) with significantly increased brightness were isolated. Their high applicability for plant-bacteria interaction studies was shown by confocal laser scanning microscopy tracking of FP-tagged B. mycoides strains after inoculation to Chinese cabbage plants in a hydroponic system. During the process of colonization, strain EC18 rapidly attached to plant roots and formed a multicellular matrix, especially at the branching regions of the root hair, which probably constitute entrance sites to establish an endophytic lifestyle. The universal applicability of the novels FPs was proven by expression from a weak promoter, dual-labelling of B. mycoides, and by excellent expression and detectability in additional soil- and rhizosphere-associated Bacillus species.

The mutualistic relationship that the garden ant Lasius niger (L.) establishes with trophobiotic homopterans makes this ant an unwelcome host in commercial crops, as ants improve the survival of homopteran pests from which they collect honeydew as a source of carbohydrates. Because the offering of alternative sugar sources can be used to disrupt this relationship, the present study explored L. niger's preference towards sugar and amino acid components that may be used in sugar solutions to increase their attractiveness. We tested the ant's preference between basic sugars (mono- and disaccharides) used as main ingredients and attractants (trisaccharides and amino acid (AA) sources) added to basic sugar in small amounts. Results showed that ants preferred disaccharides over monosaccharides, and that trisaccharides increased the attractiveness of sucrose solutions, albeit not when a protein source was added to the mix. In the case of AA sources, ants preferred components with a more diverse composition. In conclusion, trisaccharides and AA sources can be used to increase the attractiveness of sugar solutions, leading to the development of solutions that when supplied in artificial feeders can out-compete honeydew and disrupt harmful ant-homopteran mutualisms in agriculture.

[EN] The production of new generation of wood preservatives (without addition of a co-biocide) in combination with an exchange of wood poles on identical sites with high fungal inoculum, has resulted in an increase of premature failures of wood utility poles in the last decades. Wood destroying basidiomycetes inhabiting sites where poles have been installed, have developed resistance against wood preservatives. The objective of the in vitro studies was to identify a Trichoderma spp. with a highly antagonistic potential against wood destroying basidiomycetes that is capable of colonizing Cu-rich environments. For this purpose, the activity of five Trichoderma spp. on Cu-rich medium was evaluated according to its growth and sporulation rates. The influence of the selected Trichoderma spp. on wood colonization and degradation by five wood destroying basidiomycetes was quantitatively analyzed by means of dry weight loss of wood specimens. Furthermore, the preventative effect of the selected Trichoderma spp. in combination with four Cu-based preservatives was also examined by mass loss and histological changes in the wood specimens. Trichoderma harzianum (T-720) was considered the biocontrol agent with higher antagonistic potential to colonize Cu-rich environments (up to 0.1% CuSO4 amended medium). T. harzianum demonstrated significant preventative effect on wood specimens against four wood destroying basidiomycetes. The combined effect of T. harzianum and Cu-based wood preservatives demonstrated that after 9 months incubation with two wood destroying basidiomycetes, wood specimens treated with 3.8 kg m-3 copper-chromium had weight losses between 55±65%, whereas containers previously treated with T. harzianum had significantly lower weight losses (0±25%). Histological studies on one of the wood destroying basidiomycetes revealed typical decomposition of wood cells by brown-rot fungi in Cu-impregnated samples, that were notably absent in wood specimens previously exposed to T. harzianum. It is concluded that carefully selected Trichoderma isolates can be used for integrated wood protection against a range of wood destroying basidiomycetes and may have potential for integrated wood protection in the field., The authors are pleased to acknowledge the financial support by the Swiss CTI (Project No. 17001.1 PFLS-LS).

This study was conducted to determine whether various food resources enhanced the longevity and fecundity of the egg parasitoid Trichogramma brassicae Bezdenko, 1968 (Hymenoptera: Trichogrammatidae) under laboratory conditions (25°C, 65% RH, 16L:8D h photoperiod) at Laboratory of Biological Control, Department of Plant Protection, Agriculture Faculty, Namık Kemal University in 2014. Newly hatched female wasps were fed on Ephestia kuehniella Zeller, 1879 (Lepidoptera: Pyralidae) eggs with either honey, grape molasses and royal jelly as a main food, alone or double combination of this main foods or supplemented with resin (derived from plants), acacia nectar, Paulownia nectar, red tulip nectar, yellow asphodel nectar, apple syrup, liquid of E. kuehniella eggs or mashed E. kuehniella larvae. Trichogramma brassicae, females that were fed on honey and acacia nectar (17.47 d), honey + apple syrup (17.20 d), honey (16.93 d) and honey + Paulownia nectar (16.60 d) lived significantly longer than females that fed on other floral nectars and artificial diets. Females were fed on royal jelly + mashed E. kuehniella larvae (1.40 d) had the shortest longevity. Trichogramma brassicae females that were fed on honey (106.8 eggs), honey + acacia nectar (105.4 eggs), Paulownia nectar (103.13 eggs) parasitized significantly more hosts than females that fed on other floral nectars and artificial diets. Females fed on royal jelly were had the lowest parasitizing ability (3.33 eggs). These results showed that providing T. brassicae with honey, honey + acacia nectar, honey + apple syrup resulted in greater longevity and total fecundity than other food resources., Bu çalışma, çeşitli besin kaynaklarının yumurta parazitoiti Trichogramma brassicae Bezdenko, 1968 (Hymenoptera: Trichogrammatidae)’e etkilerinin araştırılması amacıyla Namık Kemal Üniversitesi, Ziraat Fakültesi, Bitki Koruma Bölümü, Biyolojik Mücadele Laboratuvarı’nda laboratuvar koşullarında (25°C sıcaklık, %65 nem, 16:8 saat (aydınlık: karanlık) aydınlanma periyodu) 2014 yılında yürütülmüştür. Ergin dişi bireyler, değirmen güvesi Ephestia kuehniella Zeller, 1879 (Lepidoptera: Pyralidae) yumurtaları üzerinde ana besin (bal, üzüm pekmezi ve arı sütü) ve ara besin (reçine (bitkilerden salgılanan), akasya nektarı, çin kavağı nektarı, kırmızı lale nektarı, sarızambak nektarı, elma şurubu, E. kuehniella yumurta sıvısı ve ezilmiş E. kuehniella larvası) ve bu ana besinlerin ikili kombinasyonları ile beslenmiştir. Bal + akasya nektarı (17.47 gün), bal + elma şurubu (17.20 gün), bal + çin kavağı nektarı (16.60 gün) ile beslenen bireylerin diğer besin ve nektar ile beslenen bireylere göre daha uzun yaşadığı belirlenmiştir. En kısa ömür ise arı sütü + ezilmiş E. kuehniella larvası (1.40 gün) ile beslenen bireylerde görülmüştür. Çalışma sonucunda toplam parazitlenen yumurta sayısı, bal (106.8 yumurta), bal + akasya nektarı (105.4 yumurta), çin kavağı nektarı (103.13 yumurta) ile beslenen bireylerde ve belirgin olarak diğer besin ile beslenen bireylerin parazitledikleri yumurta sayılarından fazla bulunmuştur. Arı sütü ile beslenen bireylerin parazitledikleri yumurta sayısı (3.33 yumurta) en düşük olarak belirlenmiştir. Bu sonuçlar, T. brassicae'ye bal, bal + akasya nektarı, bal + elma şurubu verilmesinin diğer gıda kaynaklarına göre daha uzun ömür ve toplam doğurganlık sağladığını göstermiştir.

Immobilized preys are routinely used in agro-ecological exposure studies to quantify predation of pests under field conditions, but this method has not been validated. Our purpose was to determine the validity of using immobilized adults of the major rice pest Nilaparvata lugens, brown plant hopper (BPH), as sentinels. We used direct observation by video recording to determine the causal agents of removal of field exposed BPH sentinels with two experiments: 1) we recorded removal events of dead, immobilized BPH; and 2) we compared removal of (i) dead, immobilized BPH, (ii) live, immobilized BPH, and (iii) live, mobile BPH. Long-horned grasshoppers were responsible for most removals of dead, immobilized BPH, in both experiments. Predatory ground beetles removed most of the live, immobilized BPH, whereas frogs were the major predators of live, mobile BPH. Overall, we showed that removal of immobilized sentinel prey is not representative for predation of live, mobile prey, stressing the need for a critical assessment of commonly used sentinel methods. In addition, we found that frogs played the major role in predation of BPH in rice. As current strategies to enhance biocontrol of planthoppers in rice focus on arthropod natural enemies, this finding could have major implications.

Particular groups of plant-beneficial fluorescent pseudomonads are not only root colonizers that provide plant disease suppression, but in addition are able to infect and kill insect larvae. The mechanisms by which the bacteria manage to infest this alternative host, to overcome its immune system, and to ultimately kill the insect are still largely unknown. However, the investigation of the few virulence factors discovered so far, points to a highly multifactorial nature of insecticidal activity. Antimicrobial compounds produced by fluorescent pseudomonads are effective weapons against a vast diversity of organisms such as fungi, oomycetes, nematodes, and protozoa. Here, we investigated whether these compounds also contribute to insecticidal activity. We tested mutants of the highly insecticidal strains Pseudomonas protegens CHA0, Pseudomonas chlororaphis PCL1391, and Pseudomonas sp. CMR12a, defective for individual or multiple antimicrobial compounds, for injectable and oral activity against lepidopteran insect larvae. Moreover, we studied expression of biosynthesis genes for these antimicrobial compounds for the first time in insects. Our survey revealed that hydrogen cyanide and different types of cyclic lipopeptides contribute to insecticidal activity. Hydrogen cyanide was essential to full virulence of CHA0 and PCL1391 directly injected into the hemolymph. The cyclic lipopeptide orfamide produced by CHA0 and CMR12a was mainly important in oral infections. Mutants of CMR12a and PCL1391 impaired in the production of the cyclic lipopeptides sessilin and clp1391, respectively, showed reduced virulence in injection and feeding experiments. Although virulence of mutants lacking one or several of the other antimicrobial compounds, i.e., 2,4-diacetylphloroglucinol, phenazines, pyrrolnitrin, or pyoluteorin, was not reduced, these metabolites might still play a role in an insect background since all investigated biosynthetic genes for antimicrobial compounds of strain CHA0 were expressed at some point during insect infection. In summary, our study identified new factors contributing to insecticidal activity and extends the diverse functions of antimicrobial compounds produced by fluorescent pseudomonads from the plant environment to the insect host., Frontiers in Microbiology, 8, ISSN:1664-302X

International audience; Microorganisms comprise the majority of earth's biodiversity and are integral to biosphere processes. Biological invasions are no exception to this trend. The success of introduced macroorganisms can be deeply influenced by diverse microorganisms (bacteria, virus, fungus and protozoa) occupying the whole range of species interaction outcomes, from parasitism to obligate mutualism. This large range of interactions, often coupled with complex historical and introduction events, can result in a wide variety of ecological dynamics. In this chapter, we review different situations in which microorganisms affect biological invasions. First, we consider outcomes of microorganism loss during the introduction of alien species. Second, we discuss positive effects of microorganisms on the invasiveness of their exotic hosts. Third, we examine the influence of microorganisms hosted by native species on the success of introduced species. Finally, in an applied perspective, we envisage how microorganisms can be used (i) to better decipher invasion processes and (ii) as biological control agents.

Chitin and its derivatives are natural biopolymers that are often used as compounds for the control of soilborne plant pathogens. In spite of recent advances in agricultural practices involving chitin amendments, the microbial communities in chitin-amended soils remain poorly known. The objectives of this study were (1) to investigate the bacterial diversity and abundance in an agricultural soil supplemented with chitin that turned disease-suppressive and (2) to assess the emergence of chitinolytic bacteria under conditions of raised soil pH. Amplicon pyrosequencing of soil-extracted DNA based on the 168 rRNA genes was used to characterize the structures of bacterial communities in soil, chitin-amended or not, with native versus raised pH (5.7 vs 8.7), in microcosms and the field. As a result of chitin addition, changes in the relative abundances of Actinobacteria, Proteobacteria and Bacteroidetes were observed in the field soil. A large and significant increase of the relative abundance of Oxalobacteraceae (Betaproteobacteria, Burkholderiales) was found. Within the Oxalobacteraceae, the genera Duganella and Massilia showed large increases. Moreover, responses of the Alpha- and Gammaproteobacteria appeared shortly after the alteration of the soil pH in the microcosms. A significant decrease in the abundance of Actinobacteria was observed in the chitin-amended field soil and in the microcosm at high pH. Overall, the bacterial abundance in soil tended to decrease with the addition of chitin. Two groups, Actinobacteria and Oxalobacteraceae, were found to be most responsive to the amendment. These results enhance the understanding of responses to chitin and possible interactions within bacterial communities in soil that can be correlated to soil disease suppressiveness. (C) 2014 Elsevier Ltd. All rights reserved.

Knowledge about the orientation mechanisms used by two important predaceous mirids (Macrolophus pygmaeus Rambour and Nesidiocoris tenuis (Reuter)) in finding their prey (whitefly Bemisia tabaci (Gennadius) and the tomato borer Tuta absoluta (Meyrick)) is limited. In a Y-tube olfactometer, we tested the behavioral responses of naïve and experienced predators to uninfested plants, herbivore-induced plant volatiles (HIPVs) from plants infested with T. absoluta and/or B. tabaci, the sex pheromone of T. absoluta, and volatiles produced by plants injured by the predators. Nesidiocoris tenuis responds to volatiles produced by uninfested plants only after experience with the plant, whereas naïve and experienced M. pygmaeus show positive chemotaxis. Both predators are attracted to volatiles from prey-infested plants, and we provide the first evidence that experience affects this response in M. pygmaeus. Infestation of the same plant by both prey species elicited similar responses by the two predators as plants infested by either herbivore singly. Neither predator responded to sex pheromones of T. absoluta. Macrolophus pygmaeus avoided plants injured by conspecifics, while N. tenuis females were attracted by such plants. The implications of these results for augmentative biological control are discussed.

Understanding and disentangling different processes underlying the assembly and diversity of communities remains a key challenge in ecology. Species can assemble into communities either randomly or due to deterministic processes. Deterministic assembly leads to species being more similar (underdispersed) or more different (overdispersed) in certain traits than would be expected by chance. However, the relative importance of those processes is not well understood for many organisms, including terrestrial invertebrates. Based on knowledge of a broad range of species traits, we tested for the presence of trait underdispersion (indicating dispersal or environmental filtering) and trait overdispersion (indicating niche partitioning) and their relative importance in explaining land snail community composition on lake islands. The analysis of community assembly was performed using a functional diversity index (Rao's quadratic entropy) in combination with a null model approach. Regression analysis with the effect sizes of the assembly tests and environmental variables gave information on the strength of under- and overdispersion along environmental gradients. Additionally, we examined the link between community weighted mean trait values and environmental variables using a CWM-RDA. We found both trait underdispersion and trait overdispersion, but underdispersion (eight traits) was more frequently detected than overdispersion (two traits). Underdispersion was related to four environmental variables (tree cover, habitat diversity, productivity of ground vegetation, and location on an esker ridge). Our results show clear evidence for underdispersion in traits driven by environmental filtering, but no clear evidence for dispersal filtering. We did not find evidence for overdispersion of traits due to diet or body size, but overdispersion in shell shape may indicate niche differentiation between snail species driven by small-scale habitat heterogeneity. The use of species traits enabled us to identify key traits involved in snail community assembly and to detect the simultaneous occurrence of trait underdispersion and overdispersion.

Provision of additional floral resources in the crop is a successful strategy of conservation biological control for attracting several natural enemies including predatory syrphids. However, the selection of flower species is mainly based on visiting preferences, paying little attention to the link between preference and performance. In this study, we assess the influence of feeding on flowers of two insectary plants (sweet alyssum and coriander) and flowers of a crop species (sweet pepper) on performance of the parental and first generation of the syrphid Sphaerophoria rueppellii (Wiedemann) (Diptera: Syrphidae). We found that floral preference of the adults was linked to developmental performance of their offspring. Sweet alyssum was the flower most frequently visited by syrphid adults, enhancing adult body size and egg-to adult survival of the F1 generation. RAJ gratefully acknowledges funding through the JAE Predoc CSIC scholarship program (JAEPre_08_00457). The Authors acknowledge the financial support from the Spanish Ministry of Science and Education (AGL2005-01449/AGR project).

There is an urgent need to test and develop sustainable methods for management of soil pathogens, such as the root-lesion nematode Pratylenchus penetrans and the soil fungus Verticillium dahliae. Ultimately this should be investigated with a multidisciplinary approach, with long-term measurements of biological and chemical parameters and their final impact on crop yield under field conditions. The present study focusses on eight soil health treatments (compost, chitin, marigold, grass–clover, biofumigation, anearobic soil disinfestation, a physical control method and a combination of marigold, compost and chitin) and two control treatments (a chemical control with 300 L/ha Metam sodium and un untreated control). These 10 treatments were studied for their effects on soil chemical quality, soil pathogens and their impact on the yield of potato, lily and carrots during 6 years. The present study did demonstrate that in comparison to chemical control, additions of chitin, anaerobic soil disinfestation and marigold are already excellent alternatives for the control of plant-parasitic nematodes and V. dahliae. We also demonstrated that grass–clover, biofumigation, Cultivit and compost are not effective alternatives for chemical control yet and further development is needed. All treatments caused a yield increase in comparison with the control. The biggest increases of more than 60% were found for the treatments with chitin. Furthermore it was demonstrated that these yield increases were probably less influenced by changes in chemical soil properties, but the consequence of changes in the soil biota, in this case especially the effective control of P. penetrans and V. dahliae. Furthermore it has been demonstrated that most of these soil health treatments could already be implemented in an arable crop rotation and probably adapted for many areas of the world where other alternatives, such as solarisation or soil flooding, are not feasible or too risky.

International audience; The aim of this study was to investigate the influence of volatile compounds from four secondary host plants on the ability of [i]Dinarmus basalis[/i] Rond. (Hymenoptera: Pteromalidae) to locate, recognize, and parasitize its host, 4th instar larvae or pupae of [i]Callosobruchus maculatus[/i] F. ([i]Coleoptera: Chrysomelidae[/i]). To examine this, strains of [i]D. basalis[/i] were transferred from cowpea seeds [i](Vigna unguiculata[/i] (L.) Walp. (Fabales: [i]Fabaceae[/i])) to pigeon pea ([i]Cajanus cajan[/i] (L.) Millsp.) and two varieties of Bambara groundnut ([i]Vigna subterranea[/i] (L.) Verdc.) seeds. The ability of D. [i]basalis[/i] females to recognize the volatile compounds emanating from their complex host plant was tested by using a Y-tube olfactometer and a three-dimensional device. The results suggest that when females have a choice between pure air and the air emanating from their complex host of origin, they are attracted to the air tainted by the volatile compounds they have become accustomed to. They spent significantly more time (p < 0.0001) in the branch of the tube leading to the odorous air than in the tube leading to the pure air. When females from pigeon pea seed hosts were offered a choice between cowpea and pigeon pea seeds, all containing 4th instar larvae, the familiar odor of pigeon pea seeds were most attractive. When females from Bambara groundnut (white and striped) seed hosts were offered a choice between cowpea and pigeon pea seeds, all containing 4th instar larvae, they were significantly attracted to the odour of cowpea seeds. In the three-dimensional system, the females from the four strains did not appear to have any preference for a given type of seed containing 4th instar larvae or pupae. The parasitism rate remained high on all four types of seeds used. These results show that the use of D. [i]basalis[/i] as a biological control agent is possible in host changing situations where C. maculatus starts to attack other legumes. The results of this study also provide information supporting the behavioral plasticity of D. [i]basalis[/i]. Understanding the mechanisms involved in the adaptive phenomena of biological control agents is discussed in the context of the development of adequate methods of pest control.

This paper summarises workshop discussions at the 5th international MYCORED meeting in Ottawa, Canada (June 2012) with over 200 participants representing academics, government and industry scientists, government officials and farming organisations (present in roughly equal proportions) from 27 countries. Workshops centred on how mycotoxins in food and feed affect value chains and trade in the region covered by the North American Free Trade Agreement. Crops are contaminated by one or more of five important mycotoxins in parts of Canada and the United States every year, and when contaminated food and feed are consumed in amounts above tolerable limits, human and animal health are at risk. Economic loss from such contamination includes reduced crop yield, grain quality, animal productivity and loss of domestic and export markets. A systematic effort by grain producers, primary, transfer, and terminal elevators, millers and food and feed processers is required to manage these contaminants along the value chain. Workshops discussed lessons learned from investments in plant genetics, fungal genomics, toxicology, analytical and sampling science, management strategies along the food and feed value chains and methods to ameliorate the effects of toxins in grain on animal production and on reducing the impact of mycotoxins on population health in developing countries. These discussions were used to develop a set of priorities and recommendations.

Establishing continuous and reliable colonies of pest-parasitoid systems in the laboratory is an essential requirement for carrying out manipulative experiments on biological control. Here we describe in detail the rearing protocols that we optimized for the efficient rearing of the cabbage moth Mamestra brassicae and its key parasitoid Microplitis mediator.

BACKGROUND Polygodial, a sesquiterpene dialdehyde of the drimane family, has been shown to have deterrent and antifeedant effects on various insect species, including Myzus persicae (Sulzer), Spodoptera spp. and Leptinotarsa decemlineata (Say). This compound may have potential as a broad-spectrum biocontrol agent, similar to pyrethrins, given that it was previously reported to improve yield when sprayed on barley fields. RESULTS This study compares the deterrent effect of polygodial and pyrethrins against the silverleaf whitefly Bemisia tabaci (Gennadius) and the green peach aphid M. persicae in dual-choice assays using compound-coated tomato leaf discs. B. tabaci adults were deterred by polygodial at an ED50 (effective dose at which 50% of the insects are deterred) of about 25 µg g-1 fresh weight (FW), and green peach aphids at about 54 µg g-1 FW. Bioassays were benchmarked with pyrethrins that had a 20-fold lower ED50 of approximately 1.4 µg g-1 FW against whiteflies, but only a twofold lower ED50 (about 28 µg g-1 FW) against peach aphids. Polygodial showed moderate phytotoxic effects (score of 2 on a scale of 1–5) on tomato leaves at concentrations above the ED50 concentrations (=90 µg g-1 FW). CONCLUSION The sesquiterpene dialdehyde polygodial is 2–20 times less deterrent than pyrethrins, depending on the insect species, but it could provide a useful complement to pyrethrin sprays as it has a different mode of action, is food grade and has low volatility. However, a formulation that reduces the risks of phytotoxic effects should be developed. © 2013 Society of Chemical Industry

[KEYWORDS: Agriculture Ecosystem services Land use Management optimization Soil Urban Trade-off] On-going human population growth and changing patterns of resource consumption are increasing global demand for ecosystem services, many of which are provided by soils. Some of these ecosystem services are linearly related to the surface area of pervious soil, whereas others show non-linear relationships, making ecosystem service optimization a complex task. As limited land availability creates conflicting demands among various types of land use, a central challenge is how to weigh these conflicting interests and how to achieve the best solutions possible from a perspective of sustainable societal development. These conflicting interests become most apparent in soils that are the most heavily used by humans for specific purposes: urban soils used for green spaces, housing, and other infrastructure and agricultural soils for producing food, fibres and biofuels. We argue that, despite their seemingly divergent uses of land, agricultural and urban soils share common features with regards to interactions between ecosystem services, and that the trade-offs associated with decision-making, while scale- and context-dependent, can be surprisingly similar between the two systems. We propose that the trade-offs within land use types and their soil-related ecosystems services are often disproportional, and quantifying these will enable ecologists and soil scientists to help policy makers optimizing management decisions when confronted with demands for multiple services under limited land availability.

The bronze bug, Thaumastocoris peregrinus Carpintero et Dellape (Heteroptera Thaumastocoridae), is one of the most important emerging pests of Eucalyptus LHeritier plantations worldwide. In the development of strategies to control this pest, establishing effective rearing protocols is fundamental to future research programs. We assessed life-history parameters of the bronze bug in a newly designed mass rearing strategy. Separated units were set up to contain different developmental stages. Egg production by females reared on commonly found Eucalyptus grandis Hill ex Maiden and Eucalyptus tereticornis Smith was evaluated in order to determine which plant species to use in rearing. Females laid more eggs on E. tereticornis than on E. grandis, so the former species was chosen for the rearing. A cohort of 207 eggs was followed in Petri dishes until the last individual died or reached the adult stage. We followed egg production by 15 adult couples from the original cohort. Preparation of 150-200 dishes with hatching eggs per week allows for an average production of 7,500 eggs per week. Under our rearing conditions, eggs started hatching on day six, and the first adults were obtained 23 days after oviposition. Almost half of the eggs did not hatch, and the highest nymphal mortality was recorded in the second instar, while the lowest mortality occurred in the last instar. We discuss the relevance of this mass rearing strategy, both within the context of basic behavioural studies of T. peregrinus, and as a tool for the mass rearing of the biological control agent, Cleruchoides noackae Lin et Huber.