Search

The cucurbitaceae family comprises of economically important vegetable crops grown for food and medicine. Most cucurbit crops produce cucurbitacins in leaves, flowers, fruit, seed and roots which possess various pharmacological and pharmaceutical values. Cucurbitacins are toxic to pests and diseases, and allelopathic to noxious weeds thus providing opportunities for improving tolerance to biotic stresses. Further, cucurbitacins are responsive to environmental stimuli and can therefore enhance tolerance to abiotic stress. The objective of this review was to highlight the breeding value of cucurbitacins to develop cucurbitacins-enriched genotypes for food and medicine, and for management of biotic and abiotic stresses. The following themes were discussed: a comparative analysis of cucurbitacin concentrations in edible and non-edible plant parts; genetic control and associated quantitative trait loci and molecular markers associated with cucurbitacins; pharmacological and pharmaceutical values of cucurbitacins, and potential applications for management of biotic and abiotic stresses. Results of the present study will guide genetic improvement of cucurbitacins for use as food and medicine, and in the development of genotypes tolerant to biotic and abiotic stresses.

The biology of the weed goat’s-rue, Galega officinalis (Fabaceae), is reviewed. Introduced to Canada in the late 19th Century as an ornamental, it has become established at scattered localities and is spreading locally in southern Ontario. The plant is considered a noxious weed and is legally regulated in many jurisdictions due to the production of toxic alkaloids and its invasive characteristics. Primarily a weed of pastures, grasslands and perennial crops, it also displaces native vegetation in areas where it becomes established. Originally endemic in the Black Sea region, it was spread by humans through Europe and eastward to Pakistan as a herbal medicine. More recently it has been introduced widely as a forage and ornamental plant. As a folk remedy it has been used primarily to treat diabetes in humans and to enhance milk production in both humans and livestock. The plant has also been used as a forage by limiting consumption to early growth stages and the quantity ingested. Effective control has been achieved with 2,4-D, dicamba, tryclopyr, metsulfuron methyl and other herbicides. Goat’s-rue forms a highly specific nitrogen-fixing symbiosis with the soil bacterium Neorhizobium galegae symbiovar officinalis. Successful establishment of Goat’s rue in new regions depends on the co-introduction of plant and bacterium. The lack of long-distance dispersal adaptations, soil pH requirements and its symbiont dependency, reduces the ability of G. officinalis to spread into novel areas without anthropogenic activities. These constraints to establishment may facilitate management and eradication strategies.

Murray-Darling Freshwater Research CentreMDFRC item.Management of aquatic weeds is often handled primarily at the local level. However, both water and water weeds do not recognise political boundaries even when these coincide with rivers or catchment areas. Thus potentially effective management of a weed in one area may be undermined by absence of a complementary program of management in an adjacent area. Authorities in each of the eight States or Territories that make up Australia are separately responsible for managing water weeds in their own State or Territory. Originally there was little coordination of these programs, but during the 1980s a national strategy for control of Australian water weeds has been progressively devised and put into practice. This stresses prevention and includes policies on plant importation, nomination of noxious weeds, development of a research strategy, a public awareness campaign, guidelines on the use of herbicides in or near water, and a field guide. This strategy is currently being incorporated into a National Weeds Strategy.

Cyperus esculentus (yellow nutsedge) is an alien species that started to spread in arable fields in Slovenia and has already become a noxious weed. In this study we present the spatio-temporal pattern of this invasion in Slovenia. Species was first recorded in 1980 and currently two hotspots are evident (Ljubljana Basin and Posočje). Habitat preferences of Cyperus esculentus and the floristic compostion of invaded plant communities were studied. These communites were compared to similar communities in Slovenia and to so far described vegetation types with dominating Cyperus esculentus in Europe. Based on these analyses we described new weed association, namely Digitario sanguinalis-Cyperetum esculenti.

The results of the study of toxicity level for the lamb's quarters (Chenopodium album L.) of well-known herbicides used in soybean crops as well as herbicides promising for soybean production in the Far East are presented. Lamb's quarters (Chenopodium album L.) is a highly noxious weed species that is widespread in the south of the region. Weediness monitoring conducted in 2006-2020 showed that this species was present in the Primorsky Territory on 63-100% of fields occupied by soybeans with an average growth density of 3-117 pcs/m2. In 2013-2020 in a series of experiments, conducted in the conditions of the vegetation house and on the experimental fields of the institute, the toxicity level for Common lamb's quarters was determined by 20 herbicides (based on 14 active substances) used in soybean crops. It was found that the control of this weed species is most effective when applying herbicides in the soil and treating plants with a height of up to 4-11 cm at the early stages of development - 1-3 pairs of leaves. Reliable suppression of lamb's quarters in experiments was provided by the soil (before sowing or before soybean seedlings) use of herbicides containing active substances metribuzin, imazetapir, trifluralin, pendimetalin and acetochlor. Among the active ingredients of the tested foliar herbicides, fomesafen, combinations of bentazone + acifluorfen and imazamox + chlorimuron-ethyl were the most toxic for lamb's quarters. It is recommended to use the following herbicidal preparations to control the spread of lamb's quarters: before sowing or sprouting of soybeans - Lazurit, Zenkor Ultra, Pivot, Proponit, Fabian; for processing vegetative plants - Flex, Galaksi Top, Concept, Classic Forte (Harmony Classic), Proponit.

Barnyardgrass (Echinochloa spp.) is the most common noxious weed in rice paddies as it inhibits rice growth and reduces grain yield. To date, little information is available on above- and belowground-growth changes in rice due to neighboring barnyardgrass. This study aimed to investigate the changes in root traits and shoot growth of rice when it is grown with different kinds of barnyardgrass. Japonica rice plants (var. Nanjing 9108) were co-cultured with two varieties of Echinochloa crusgalli (L.) Beauv. (EP, var. mitis (pursh) Petern; EH, var. zelayensis (H.B.K.) Hitchc), and E. colonum (L.) Link (EL) in the field in 2017 and 2018. Four treatments included control (i.e., weed free rice plants) and co-cultures with each of three barnyardgrasses (EP, EH, and EL). The results revealed that EP, EH, and EL treatments significantly reduced rice grain yields by 30.6%–36.2%, 42.5%–46.5%, and 10.6%–14.3%, respectively. Shoot growth including shoot dry weight, leaf photosynthetic rate, zeatin (Z) and zeatin riboside (ZR) in grains, and activities of key enzymes involved in sucrose-to-starch conversion in grains and root traits, such as length density, root dry weight, total absorbing surface area, active absorption surface area, oxidation activity, and Z + ZR contents in roots were dramatically reduced during post-heading stages of rice when grown with the three kinds of barnyardgrass. Moreover, above-mentioned rice shoot growth indices were strongly and positively correlated with root traits. These results suggested the decrease in rice shoot growth and root traits during post-heading stages contributes to the reduction in the rice yield when it grows with barnyardgrass neighbors.

A thorough understanding of the emergence pattern and persistence of weed seeds is a prerequisite in framing appropriate weed management options for noxious weeds. In a study conducted at the University of Queensland, Australia, the emergence and seed persistence behavior of three major weeds Sonchus oleraceous, Rapistrum rugosum, and Argemone mexicana were explored with seeds collected from Gatton and St George, Queensland, Australia, with an average annual rainfall of 760 and 470 mm, respectively. Seed persistence was evaluated by placing seeds at the surface layer (0 cm) or buried at 2 and 10 cm depths enclosed in nylon mesh bags and examined their viability for 42 months. In another study, the emergence pattern of four populations, each from these two locations, was evaluated under a rainfed environment in trays. In the mesh-bag study, rapid depletion of seed viability of S. oleraceous from the surface layer (within 18 months) and lack of seed persistence beyond two years from 2 and 10 cm depths were observed. In trays, S. oleraceous germinated 3 months after seeding in response to summer rains and there was progressive germination throughout the winter season reaching cumulative germination ranging from 22 to 29% for all the populations. In the mesh-bag study, it took about 30 months for the viability of seeds of R. rugosum to deplete at the surface layer and a proportion of seeds (5 to 13%) remained viable at 2 and 10 cm depths even at 42 months. Although fresh seeds of R. rugosum exhibit dormancy imposed due to the hard seed coat, a proportion of seeds germinated during the summer months in response to summer rains. Rapid loss of seed viability was observed for A. mexicana from the surface layer; however, more than 30% of the seeds were persistent at 2 and 10 cm depths at 42 months. Notably, poor emergence was observed for A. mexicana in trays and that was mostly confined to the winter season.

Herbicide resistance in crop plants is valuable for integrated weed management in agriculture. Herbicide resistant rice, in particular, is important to management of weedy rice, a close relative of cultivated rice and a noxious weed prevalent in rice fields that remains challenging to farmers worldwide. Herbicide resistant plants can be obtained through transgenic approach or by mutagenesis of regular plant and screening of mutants with elevated resistance to herbicide. In this study, we conducted ethyl methyl sulfonate mutagenesis (EMS) to elite indica cultivar Huanghuazhan (HHZ) and screened for mutants resistant to imazapic, a herbicide that can inhibit the acetolactate synthase (ALS) in plants. We obtained three mutants of OsALS gene that have not been reported previously in rice. One of the mutants, with Trp548 changed to Met (W548M), was analyzed in more details in this study. This mutation had no negative effect on the plant physiology and morphology as well as rice yield. Compared with the imidazolinone-resistant mutant S627N (Ser627 changed to Asn) that has been deployed for Clearfield rice development, W548M mutant showed high levels of resistance to a broad spectrum of five families of ALS-inhibiting herbicides, in addition to a higher level of resistance to herbicides of the imidazolinone family. The herbicide-resistance was stably inherited by crossing into other rice lines. Thus, the W548M mutation provides a valuable resource for breeding of herbicide resistant rice and weed management.

A survey was conducted at farmers fields in five upazilas of Sirajganj district to find out farmers knowledge on crop-weed association in different field crops, crop yield losses and weeds act as alternate hosts for insect-pathogen during 2019 to 2020 cropping seasons. Primary data were collected from the respondents through a well-oriented structural questionnaire. A total of 40 weed species, belong to 35 genera under 21 families, were identified from 8 different field crops. The highest crop-weed association was found in rice (40:192) and the lowest in mustard (106:50). The maximum weed management cost was occurred in rice (38,900 Tk. ha1). Weed caused 8 to 51% yield loss in different field crops. Our results revealed that Mutha emerged as the major noxious weed for six field crops of this district. Weeds acted as alternate hosts of various insects and pathogens. According to farmers opinion, weed is also used as fodder, mulch, compost, vegetables, fish feed, medicinal and ornamental purposes at their locality. Therefore, the present study provides information to extension workers and researchers about the noxious weeds and their crop-weed association, other harmful and beneficial effects of weeds, for better, sustainable, and eco-friendly weed management practices. [J Bangladesh Agril Univ 2021; 19(2.000): 215-222]

Aim: This research was conducted to assess the allelopathic potential of 100 plants species, including noxious weeds and medicinal plants of Malaysia as donor plant on the growth of Lactuca sativa (lettuce) as the recipient plant. This study was also carried out to justify common weeds found in Malaysia to act as a natural herbicide for weed management through allelopathy phenomenon. Methodology: Weed and medicinal plant species commonly found in Malaysia were identified according to their morphological characteristics. Sandwich method was carried out to determine the allelopathic potential of weed species through leaf litter leachate mechanism. On the other hand, dish pack method was conducted to discover the allelopathic potential of weed species through volatilization pathway. Results: 100 weed species and medicinal plants commonly found in Malaysia inhibited the radicle and hypocotyl growth of L. sativa by both sandwich method and dish pack method. Among 100 weed species, Passiflora foetida showed the maximum inhibitory effects on L. sativa growth in both sandwich and dish pack method. The highest amount of P. foetida leaf litter (50 mg), completely inhibited the growth of radicle and hypocotyl of L. sativa. Volatilization of weed and medicinal plants leaf litter inhibited the growth of L. sativa with increasing distances of lettuce seed with the weed and medicinal plants leaf litter. Interpretation: The findings of this study provides a base line for identifying plants with allelopathic properties for controlling weed propagation.

Johnsongrass [Sorghum halepense (L.) Pers.] is one of the most noxious weeds distributed around the world. Due to its rapid growth, wide dissemination, seeds that can germinate after years in the soil, and ability to spread via rhizomes, S. halepense is difficult to control. From a perspective of plant pathology, S. halepense is also a potential reservoir of pathogens that can eventually jump to other crops, especially corn (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench]. As one of the most problematic weeds, S. halepense and its diseases can provide useful information concerning its role in diseases of agronomically important crops. An alternative consideration is that S. halepense may provide a source of genes for resistance to pathogens. While some studies have verified that pathogens isolated from S. halepense actually cause disease on host crops through cross inoculation, similarity of disease symptoms and pathogen morphology have been used for identity of the disease agent in most studies. Availability of DNA sequence information has greatly altered and improved pathogen identification, leading to significant changes in phylogenetic assignments. Reclassification of pathogens, especially fungi, raises new questions concerning the role of S. halepense as a disease reservoir. Our goals in this review are to pinpoint, where possible, diseases for which S. halepense acts as a significant pathogen reservoir and to point out problem areas where further research is needed.

Weeds with allelopathic effect have been reported to cause significant damage in agriculture particularly in smallholder farming systems. This study assessed the allelopathic effects of different concentrations of crude extract of a noxious weed Sphaeranthus suaveolens on seed germination and seedling growth of Phaseolus vulgaris and Oryza sativa by examining germination, seedling height, and total chlorophyll content after seven and fourteen days of crude extract treatment, respectively. Results showed that seed germination and seedling growth were significantly ( p < 0.001 ) decreased with increase in concentration of crude extract, signifying concentration dependency. Highest concentration (100%) of S. suaveolens crude extracts resulted in 90% and 100% inhibition of P. vulgaris and O. sativa seed germination, respectively. Chlorophyll content, fresh weight, and root and shoot length of both P. vulgaris and O. sativa were also significantly ( p < 0.001 ) affected by highest concentration (100%) of S. suaveolens crude extracts. Results from this study suggest that the extract of S. suaveolens contains water-soluble allelochemicals which significantly reduce growth and productivity of P. vulgaris and O. sativa.

The aim of this work was to identify weed species in areas under different soil management systems. The research was carried out in the Brazilian Agricultural Research Corporation experimental area, in the 2017/2018 harvest, in the city of Boa Vista, Roraima State, Brazil. The experimental design was randomized blocks and the treatments included of five soil management systems (native vegetation, minimum tillage, no-tillage, conventional tillage and conventional tillage with crop rotation). Weed collection, identification, counting and drying were performed and then the phytosociological indices (Relative density, relative frequency, relative abundance, importance value index, relative importance value index and dry mass) were calculated. Variance analysis with means compared by Tukey test (P

A recent series of deaths in previously healthy dogs in Victoria, Australia associated with the ingestion of raw meat contaminated by indospicine derived from native Australian plants of the Indigofera species draws attention to the potential that exists for herbal toxicity in domestic animals. Although the efficacy of herbal remedies generally remains unproven in domestic animals, herbal preparations are being increasingly used as supplements and treatments. Issues with incorrect ingredients, inadequate processing, faulty, incomplete or inaccurate product labelling, contamination with toxins, adulteration with undeclared pharmaceutical agents and herb-herb interactions are well recognized as causes of adverse effects in humans. However, apart from of the effects of noxious weed species, the literature on herbal toxicity in domestic animals is sparse. Thus, the forensic evaluation of cases of suspected poisoning in domestic animals should also encompass an accurate description the type and dose of any herbal preparations that may have been recently administered.

Purpose Considered as one of the most unwanted species by the International Union for Conservation of Nature, the Prosopis juliflora plant is a noxious and invasive weed. Recent studies suggest that the heartwood of the plant has an unusually high amounts of flavonoids with potential medicinal properties and dyeing potentials. In this work, acetonic extracts were successfully valorized into a natural dye. Design/methodology/approach After extraction and optimization of dyeing conditions, the fabric was treated by using pre-mordanting, simultaneously mordanting and post mordanting techniques. The dyed samples were then evaluated by using standard methods ISO 105-C06, ISO 105-A02, ISO 105-X12 for wash, light and rub fastness, respectively. Findings Dye fastness ranged from good to very good with mordants improving both wash and rub fastness. Optimum pH for dyeing was found to be at 7.2 at temperatures of 60°C and a dyeing time of 80 min. Application of mordant in dyeing white fabric showed improved dyeing properties in post mordanting than both pre-mordanting and simultaneous mordanting. Originality/value To best of the authors’ knowledge, this paper details for the first time how a noxious weed can be transformed into a natural dye, with potential applications to the textile industry.

Global trade has considerably accelerated biological invasions. The annual tropical teosintes, the closest wild relatives of maize, were recently reported as new agricultural weeds in two European countries, Spain and France. Their prompt settlement under climatic conditions differing drastically from that of their native range indicates rapid genetic evolution. We performed a phenotypic comparison of French and Mexican teosintes under European conditions and showed that only the former could complete their life cycle during maize cropping season. To test the hypothesis that crop-to-wild introgression triggered such rapid adaptation, we used single nucleotide polymorphisms to characterize patterns of genetic variation in French, Spanish, and Mexican teosintes as well as in maize germplasm. We showed that both Spanish and French teosintes originated from Zea mays ssp. mexicana race “Chalco,” a weedy teosinte from the Mexican highlands. However, introduced teosintes differed markedly from their Mexican source by elevated levels of genetic introgression from the high latitude Dent maize grown in Europe. We identified a clear signature of divergent selection in a region of chromosome 8 introgressed from maize and encompassing ZCN8, a major flowering time gene associated with adaptation to high latitudes. Moreover, herbicide assays and sequencing revealed that French teosintes have acquired herbicide resistance via the introgression of a mutant herbicide-target gene (ACC1) present in herbicide-resistant maize cultivars. Altogether, our results demonstrate that adaptive crop-to-wild introgression has triggered both rapid adaptation to a new climatic niche and acquisition of herbicide resistance, thereby fostering the establishment of an emerging noxious weed.

Lantana camara Linn., a noxious weed found in most places of the world has many potential aspects and has been used as folk medicines to cure several diseases. It is reported to possess antimicrobi...

The Maasai pastoralist community resides in Simanjiro District, Manyara Region, Tanzania. As a pastoralist community they are largely dependent on rangelands as a source of forage for their livestock. However, plant invasions are threatening rangeland productivity, displacing valuable forage species, leading to a reduction in livestock populations. The noxious weed Parthenium hysterophorus has recently been established in Simanjiro District and may pose a significant threat to livelihoods if effective control strategies are not put in place. This study was therefore conducted to determine pastoralists’ understanding of P. hysterophorus in Simanjiro District, Tanzania. Semi-structured and open-ended questionnaires were used to collect information on, among others, the date of introduction, means of spread, area coverage, effects of P. hysterophorus on livestock health and management control for P. hysterophorus. Pastoralists were unaware of when P. hysterophorus was introduced although they mentioned vehicles, people and livestock to be the main vectors of introduction and spread. They confirmed that P. hysterophorus has little/some expanding its range since it was first noticed at the beginning of this decade. Furthermore, most pastoralists were not aware of the effects of Parthenium weed in livestock although few reported it causing distasteful and less milk and diarrhoea after consuming the weed. There were no major efforts in place to control Parthenium weed. Therefore, efforts need to be made to motivate pastoralists through community awareness campaigns to impart knowledge on how to control P. hysterophorus to promote rangeland productivity. Also, community awareness the impacts of the weed on their livestock and human health.

Teki (Cyperus rotundus L.) merupakan salah satu gulma berbahaya pada komoditi hortikultura karena mengandung alelokimia yang dapat menghambat perkecambahan tumbuhan. Alelopati tersebut berpotensi untuk digunakan sebagai bioherbisida pratumbuh untuk mengendalikan gulma berdaun lebar dan rumput. Tujuan penelitian adalah untuk mengetahui keefektifan bioherbisida berbahan baku umbi teki pada berbagai formulasi dan dosis. Percobaan ini dilaksanakan pada bulan Maret sampai Juni 2019 di rumah kaca Kebun Percobaan Cikabayan, IPB University, Bogor, untuk penanaman biji gulma. Penelitian menggunakan rancangan rancangan acak lengkap faktorial dengan tiga ulangan. Faktor pertama adalah formulasi umbi teki (F1: tepung umbi teki, F2: tepung umbi teki + aquades, F3: tepung umbi teki + aquades + surfaktan, F4: maserat, F5: maserat + surfaktan, dan F6: pellet), dan faktor kedua adalah dosis (D1: 22.50 kg tepung ha-1, D2: 45 kg tepung ha-1, dan D3: 67.50 kg tepung ha-1) sehingga terdapat 18 unit perlakuan. Hasil percobaan menunjukkan bahwa semua formulasi bioherbisida berbahan baku tepung umbi teki efektif menekan perkecambahan. Formulasi pellet merupakan formulasi yang direkomendasikan karena dalam pengaplikasiannya lebih mudah dan efisien. Dosis efektif untuk menekan perkecambahan dan pertumbuhan kecambah tanaman uji adalah 45 kg tepung ha-1. Kata kunci : A. gangetica, A. gangeticus, E. crus-galli, maserasi, pellet

After habitat loss, drastic effects of biological invasion caused by alien invasive species to the native biodiversity have been acknowledged worldwide by the agriculturists, ecologists, and governments as it is more overwhelming than pollution, harvest and disease combined. One such example of biological invasion is P. hysterophorus which is considered to be one of the topmost noxious weeds threatening ecosystems diversity in the world, particularly in Pakistan due to its invasive success and generalist nature. Yet no studies have explored the pattern and determinants of plant biodiversity in the Parthenium dominated landscapes. Here we explored the current distribution pattern of this species with relation to environmental variables in the Malakand division of northern Pakistan. Twenty-three sites dominated by P. hysterophorus were identified through a participatory mapping process combined with traditional ecological knowledge and quantitative inventories were made. In total, we found 62 plant species in 55 genera and 32 families, predominately from Asteraceae, Poaceae, and Solanaceae. Ward’s agglomerative clustering procedure showed three well-differentiated, and ecologically meaningful but overlapping vegetation communities. P. hysterophorus was found to be the leading species with an average Importance value ranging from 33.28% to 65.59%. Based on our criteria, surprisingly we found significantly less to be fully (30%) or partially invaded (21%) than the less invaded (47%) plots, indicating the gradual invasive success of the species across the landscape. Canonical Correspondence Analysis (CCA-ordination) has explained 36.9% of the cumulative variance by the first three axes and identified elevation (r= −0.526), slope (r = 0.438) and percent sand (r=−0.474) to be the major environmental factors affecting the distribution of P. hysterophorus and associated vegetation. These results suggested that elevation and percent sand negatively affect Parthenium distribution whereas slope has a positive relationship thereby promoting its populations in the region. The generalist nature of this invasive species is likely to have an overall adverse negative effect on the ecosystem functioning and cannot be ignored. Therefore, quick actions should be taken for the management of this noxious weed to avoid economic consequences and potential threats to fragile ecosystems such as that in Malakand division.

The noxious weed Allium triquetrum (Alliaceae) has invaded widespread areas in southern Australia, forming dense monocultures that threaten indigenous ground flora. Two soilborne biocontrol agents, the fungus Stromatinia cepivora and the bacterium Pectobacterium carotovorum subsp. carotovorum (Pcc) have previously been reported as killing A. triquetrum in gnotobiotic controlled conditions. This study aimed to find why glasshouse pot trials in complex potting media and field trials showed no effect of inoculation with either agent. Bacteria were consistently isolated from inside surface-sterilised bases and bulbs of A. triquetrum. Most bacteria from actively growing plants were closely related to Bacillus but one from dormant bulbs (RPTAtOch1) belonged to Ochrobactrum. Most bacteria reduced soft rot caused by Pcc in vitro by up to 100% when inoculated the day before Pcc. Co-cultivation with Pcc reduced its extracellular pectin lyase and polygalacturonase, which target plant cell walls. RPTAtOch1 was identified as O. quorumnocens by traditional physiological, biochemical and molecular tests, whole genome sequencing and Average Nucleotide Identity comparisons. Its draft genome consisted of 76 contigs, 70% of which were closest to isolate A44 of O. quorumnocens, which antagonises soft rotting of potato by Pcc by destroying its quorum-sensing lactones but, like RPTAtOch1, does not inhibit growth of Pcc. Also, endophytic bacteria inhibited germination of S. cepivora sclerotia and so prevented white rot. Thus, the failure in biocontrol of A. triquetrum by both S. cepivora and Pcc may be due, ironically, to biocontrol of the intended pathogens by endophytic bacteria inside the target weed.

The present study aimed to analyze the chemical composition of Symphyotrichum squamatum EOs growing in two different habitats to explore the ecological implication on the EOs production and evaluate their antioxidant and allelopathic potentialities. The EOs from the aerial parts collected from coastal Mediterranean belt and inland abandoned habitats in the Nile Delta of Egypt, were extracted and analyzed using gas chromatography-mass spectrometry. Sixty compounds were characterized as overall constituents of EOs from both samples. Sesquiterpenes were the main component and represented by 69.77% and 88.68% from coastal and inland sample, respectively. The coastal sample attained a relatively high content of monoterpenes compared to the inland sample. Major compounds from the EOs of the coastal habitat sample, were humulene epoxide, (-)-spathulenol, (-)-caryophyllene oxide, germacrene D, and α-humulene representing 59.72%. However, β-pinene, germacrene D, α-humulene, α-muurolene, humulene epoxide, (-)-caryophyllene oxide, and β-cadinene were the major compounds of EOs of the inland habitat sample, representing 63.70%. The correlation analysis revealed more correlation between the Egyptian inland S. squamatum and the Japanese ecospecies. However, the Egyptian coastal S. squamatum and Turkish ecospecies were more correlated to each other. The present data suggested that chemotypes of S. squamatum maintain their typical pattern despite ecological or climatic differences. The EOs of S. squamatum showed moderate antioxidant activity, wherein coastal and inland EOs have an IC50 value of 382.53 and 559.63 μL L−1, respectively. Also, the EOs from both habitats showed moderate allelopathic activity against the noxious weed Bidens pilosa. However, the activity of the coastal sample was more than inland one and could be attributed to the content of the major compounds, especially the oxygenated terpenes. Keywords: Symphyotrichum squamatum, Essential oils, Environmental variables, PCA, Allelopathic potential, Antioxidant activity

Weed-competitive cultivars are desired in the wake of growing popularity of organic farming, environmental pollution and evolution of herbicide resistance in weeds. This research work evaluated the weed competitive ability of three forage maize cultivars (ADA-523, AGA and SASA-5) against the noxious weed barnyardgrass (Echinochloa crus-galli (L.) P.Beauv.). The study was conducted in spring 2018 and repeated in summer 2018. Results of this study showed that maize-barnyardgrass competition significantly decreased the growth of forage maize plants. For instance, barnyardgrass decreased the maize plant height by 11.9-16.9%, leaf length by 13.3-20.2%, leaf width by 20.2-27.4%, and number of leaves by 14.3-25.0%. Fresh and dry weights of maize plants were also significantly decreased as a result of weed-crop competition. Barnyardgrass decreased the shoot fresh weight (30.7-60.6%), shoot dry weight (33.3-52.2%), leaf fresh weight (33.4-56.5%) and leaf dry weight (31.9-50.0%) of the maize plants. An interactive effect of weed × maize cultivars was found non-significant. Forage maize cultivars also varied occasionally for their traits. Nevertheless, ADA-523 had a higher plant height, leaf length, leaf width, leaf fresh weight and leaf dry weight than the cultivars AGA and SASA-5. On the other hand, the cultivar SASA-5 had a higher shoot fresh weight, shoot dry weight and root fresh weight than the other cultivars in the study. This research work concluded that the forage maize cultivars in the study did not vary for the weed-competitive ability. Further, barnyardgrass-maize competition could decrease the growth and development of the maize cultivars.

Over 90% of global commercial trade occurs between seaports, which are initial points-of-entry for nonnative, potentially invasive propagules. As such, there is a need to develop means to both rapidly intercept and identify propagules as they arrive. Here, we focus on plant propagules that are assumed to be non-native, in seed form. Because standard morphological techniques alone are laborious and require taxonomic expertise, we sought to address if identification through barcoding of the plastid DNA (rbcL + matK genes) of plant seeds could improve current processes in the early detection and rapid response to prevent entry/establishment of nonnative plant species. This research conducted a preliminary foray to evaluate the utility of widely accepted plant plastid DNA barcodes to identify plant propagules (seeds, hereafter) collected from the air-intake grilles of refrigerated shipping containers of a single agricultural commodity arriving at the Port of Savannah, Georgia, USA. We ask four questions: (1) Can DNA barcoding be used to detect seeds collected from shipping containers at the port? (2) What is the genetic composition of propagules entering the port? (3) How do morphological identifications compare to those based on genetic analysis? (4) Are nonnative invasive plant species present on shipping containers entering the Port of Savannah? This research collected 11,044 seeds from 628 refrigerated shipping containers between 2015 and 2017. Seeds were then morphologically sorted into Seed Types. Barcoding of the matK and rbcL gene regions of the plastid genomes directly isolated from seeds resulted in poor amplification. This is likely due to a host of potential confounding factors. Therefore, we germinated seeds and utilized leaf-tissues for sequencing of these two gene regions. From BLASTn analyses, results returned top hits for a variety of species, with up to 22 possible nonnative plant species and one definite Federal Noxious Weed. This work investigates the interception application of DNA barcoding to improve agro- and bio-security issues posed by nonnative and invasive species. Though this study required the germination of the seeds to obtain leaf-tissue suitable for our DNA barcoding method, we effectively demonstrated seed viability. Our seed identification process was lengthy and understandably not feasible for real-time application. Therefore, we seek to improve our methods for future applications by testing other approaches that may better complement morphological identification. Next reasonable steps include improved extraction protocols, metabarcoding to generate DNA barcode sequences directly from groups of seeds harvested from shipping containers and implementing other next-generation sequencing techniques.

With a changing climate and cultivation of vast agricultural monocultures, the abundance of various pests shows an increase, and their activity is shifting, expanding, and intensifying. To avoid losses on crops, a variety of synthetic pesticides is increasingly being used to control harmful pests. This trend leads to the overuse of pesticides, which has environmental consequences, because these toxic chemicals enter the soil and water, can exhibit toxic effects on non-target organisms, and could eventually enter the food chain resulting in adverse impact on human health. Consequently, the rapid development of nanotechnologies enabled the reformulation of pesticides into nanosystems, characterized by controlled release, targeted distribution, increased efficiency, and reduced dose-dependent toxicity. In addition, so-called biopesticides, i.e. pesticides based on natural compounds, are toxic to specific pests and relatively harmless to non-target organisms and the ecosystem and could be easily formulated in various types of nanoscale preparations. This chapter gives a comprehensive overview of recent findings related to the activity and mechanisms of action of biopesticides including plant extracts and essential oils or their constituents, biopesticides produced by microorganisms, peptides obtained in spider venoms, and Cry proteins produced by Bacillus thuringiensis in their bulk as well as nanoscale form against noxious weeds and harmful arthropods causing losses of economically important crops. Special attention is also paid to the insecticidal activity of green synthesized metal nanoparticles against mosquitoes, which are important vectors of many diseases causing annually more than a million deaths in tropical regions.

Background Tea, one of the most important commercial crops on earth, is strongly affected by weeds on productivity and quality. Bioherbicides are shedding new light on weed control in tea gardens in an economical and safe manner. Results A pathogenic strain SYNJC-2-2 was isolated from diseased leaves of a noxious weed, goosegrass (Eleusine indica) from a tea garden in Zhejiang Province, China. It was identified as the fungal species Bipolaris bicolor based on the morphological characteristics and phylogenetic analysis. The potential of the B. bicolor strain SYNJC-2-2 as a bioherbicide was assessed by determining its efficacy to control weeds and selectivity to crops, its infection process and the influence of environmental conditions on conidial production and germination. The ED90 (effective dose of conidia resulting in 90 disease index) of SYNJC-2-2 on goosegrass was 2 × 104 conidia mL-1 . Additionally, three Poaceae weeds, Setaria viridis, Microstegium vimineum and Pennisetum alopecuroides, were also extremely susceptible to SYNJC-2-2. SYNJC-2-2 was safe to 14 out of 17 crop species in 9 families, especially tea plants. Conidial germination, hyphal growth and appressorial formation occurred within 3 to 6 h on goosegrass leaves. Hyphae invaded leaf tissues mainly through epidermal cell junctions and cracks, causing cell death and necrotic lesions within 2 days on inoculated leaves and killing goosegrass plants within 7 days. Furthermore, SYNJC-2-2 has a strong adaptability to environmental variables and high conidial production capacity on goosegrass juice agar media. Conclusion B. bicolor strain SYNJC-2-2 has the potential to be developed as a bioherbicide for controlling goosegrass, especially in tea gardens. This article is protected by copyright. All rights reserved.