Invertebrate Pests Research Articles

Ethnobotanical insights on the management of plant pests and diseases by smallholder farmers in Mpumalanga Province of South Africa

BackgroundPests and diseases are a major contributor to yield losses in sub-Saharan Africa, prompting smallholder farmers to seek cost-effective, accessible and ecologically friendly alternatives for crop protection. This study explored the management of pests and diseases affecting crops across eight selected villages in Ehlanzeni District, Mpumalanga Province, South Africa.MethodsA total of 120 smallholder farmers were purposefully selected utilising the snowball technique. Information on the management of plant pests and diseases was collected through interviews and focus group discussions using semi-structured interview schedules. Ethnobotanical indices, including relative frequency of citation (RFC), use-value (UV) and informant consensus factor (Fic), were used to quantify and rank the plants used for crop protection in the study area.ResultsTwenty-three plant species (16 naturalised exotics and seven indigenous plants) belonging to 16 families were used for managing pests (vertebrates and invertebrates) and diseases (fungal and bacterial related) affecting crops in the study area. The dominant (100%) crops cultivated by the participants were Allium cepa L., Mangifera indica L., Solanum lycopersicum L. and Zea mays L. The RFC value ranged from 0.08 to 0.83 and the three most popular plants for crop protection were Capsium annuum L. (0.83), A. cepa (0.63) and Dichrostachys cinerea (L.) Wight & Arn. (0.43). In terms of the UV, the five most promising plants used as biocontrol were Tulbaghia violacea (0.13), A. cepa (0.12), C. annuum L. (0.09), Solanum campylacanthum Hochst. Ex A.Rich.(0.09) and Pinus pinaster (0.08). Based on the Fic, four categories were established and dominated by fungal diseases (0.64). Furthermore, T. violacea and A. cepa were the most often mentioned plants used against fungal conditions. Other categories cited were bacterial diseases (0.3), invertebrate pests (0.11) and vertebrate pests (0.14), an indication that smallholder farmers had limited agreement or common knowledge about the plants used for their management. The preparation methods included maceration (38%), decoction (38%) and burning (24%). Foliar application (67%) and soil drenching (33%) were used for administering plant extracts during the management of crop pests and diseases.ConclusionThe study highlights the importance of botanicals and associated indigenous knowledge among smallholder farmers in Mpumalanga Province, South Africa. It is pertinent to explore the valorisation of these botanicals by generating empirical data on their biological efficacies and phytochemical profiles.

Large language models help facilitate the automated synthesis of information on potential pest controllers

Abstract The body of ecological literature, which informs much of our knowledge of the global loss of biodiversity, has been experiencing rapid growth in recent decades. The increasing difficulty of synthesising this literature manually has simultaneously resulted in a growing demand for automated text mining methods. Within the domain of deep learning, large language models (LLMs) have been the subject of considerable attention in recent years due to great leaps in progress and a wide range of potential applications; however, quantitative investigation into their potential in ecology has so far been lacking. In this work, we analyse the ability of GPT‐4 to extract information about invertebrate pests and pest controllers from abstracts of articles on biological pest control, using a bespoke, zero‐shot prompt. Our results show that the performance of GPT‐4 is highly competitive with other state‐of‐the‐art tools used for taxonomic named entity recognition and geographic location extraction tasks. On a held‐out test set, we show that species and geographic locations are extracted with F1‐scores of 99.8% and 95.3%, respectively, and highlight that the model can effectively distinguish between ecological roles of interest such as predators, parasitoids and pests. Moreover, we demonstrate the model's ability to effectively extract and predict taxonomic information across various taxonomic ranks. However, we do report a small number of cases of fabricated information (confabulations). Due to a lack of specialised, pre‐trained ecological language models, general‐purpose LLMs may provide a promising way forward in ecology. Combined with tailored prompt engineering, such models can be employed for a wide range of text mining tasks in ecology, with the potential to greatly reduce time spent on manual screening and labelling of the literature.

Dietary metabarcoding reveals the simplification of bird-pest interaction networks across a gradient of agricultural cover.

Agriculture is vital for supporting human populations, but its intensification often leads to landscape homogenization and a decline in non-provisioning ecosystem services. Ecological intensification and multifunctional landscapes are suggested as nature-based alternatives to intensive agriculture, using ecological processes like natural pest regulation to maximize food production. Birds are recognized for their role in increasing crop yields by consuming invertebrate pests in several agroecosystems. However, the understanding of how bird species, their traits and agricultural land cover influence the structure of bird-pest interactions remains limited. We sampled bird-pest interactions monthly for 1 year, at four sites within a multifunctional landscape, following a gradient of increasing agricultural land cover. We analysed 2583 droppings of 55 bird species with DNA metabarcoding and detected 225 pest species in 1139 samples of 42 bird species. As expected, bird-pest interactions were highly variable across bird species. Dietary pest richness was lower in the fully agricultural site, while predation frequency remained consistent across the agricultural land cover gradient. Network analysis revealed a reduction in the complexity of bird-pest interactions as agricultural coverage increased. Bird species abundance affected the bird's contribution to the network structure more than any of the bird traits analysed (weight, phenology, invertebrate frequency in diet and foraging strata), with more common birds being more important to network structure. Overall, our results show that increasing agricultural land cover increases the homogenization of bird-pest interactions. This shows the importance of maintaining natural patches within agricultural landscapes for biodiversity conservation and enhanced biocontrol.

Field Crop Yield Loss Calculator for Disease and Invertebrate Pests: An Online Tool from the Crop Protection Network

The Field Crop Disease and Invertebrate Loss Calculator Web Tool is an interactive online resource showcasing estimates of the yield reduction and economic impact of plant diseases and invertebrate pests over time and location. Accessible through the Crop Protection Network website ( https://www.cropprotectionnetwork.org ), this free online research tool was developed to inform agronomists and researchers across industry and academia, extension workers, commodity groups, and funding agencies about the impact of crop disease and invertebrate pests. The tool enables widespread user access through commonly used web browsers on computers, tablets, and mobile devices. Yield loss estimates are generally obtained through annual surveys of university-affiliated specialists or others with experience in crop protection. Production data are primarily obtained from U.S. and Canadian government agencies. A detailed understanding of the economic impacts of plant disease and invertebrate pests provides valuable information that can inform the allocation of resources to reduce losses in major field crops. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

IPM messaging: who, what, how?—Insights from a survey of farmers and agronomists in Scotland

Abstract Enhanced awareness and knowledge among arable (field crop) farmers and agronomists are pivotal for making informed integrated pest management (IPM) decisions. In this study, we had 3 primary objectives: (i) identifying the key factors influencing the adoption of IPM, (ii) gathering insights into the currently perceived pest threats, and (iii) identifying any necessary intervention tools or methods for modifying the flow of information. In 2021, a telephone survey involving 267 arable and arable/livestock farmers and 26 agronomists was conducted in Scotland. The survey was designed to gather information on the perceived invertebrate pest, disease, and weed threats, the extent of IPM implementation, and the sources of information consulted. Several factors influenced the uptake of IPM, including farm type, location, agronomist engagement, farmer’s age, education, and membership in schemes promoting IPM. Notably, there were disparities in perceptions of the most significant pest threats between arable farmers and agronomists. This points to a division of decision-making responsibilities and, consequently, varying information needs. Agronomists typically require technical information related to pesticide effectiveness and disease management, whereas arable farmers seek guidance on cultural approaches for managing weeds and invertebrate pests. Furthermore, preferences for information sources also differed, with agronomists showing a preference for social media as a source of IPM information, while farmers favored the farming press. Ultimately, a deeper understanding of IPM practices equips farmers to actively participate in IPM discussions with their agronomists. This enables the collaborative development of an effective IPM strategy and, in turn, increases the adoption of IPM practices.

Epichloë fungal endophyte interactions in perennial ryegrass (Lolium perenne L.) modified to accumulate foliar lipids for increased energy density

BackgroundCommercial cultivars of perennial ryegrass infected with selected Epichloë fungal endophytes are highly desirable in certain pastures as the resulting mutualistic association has the capacity to confer agronomic benefits (such as invertebrate pest deterrence) largely due to fungal produced secondary metabolites (e.g., alkaloids). In this study, we investigated T2 segregating populations derived from two independent transformation events expressing diacylglycerol acyltransferase (DGAT) and cysteine oleosin (CO) genes designed to increase foliar lipid and biomass accumulation. These populations were either infected with Epichloë festucae var. lolii strain AR1 or Epichloë sp. LpTG-3 strain AR37 to examine relationships between the introduced trait and the endophytic association. Here we report on experiments designed to investigate if expression of the DGAT + CO trait in foliar tissues of perennial ryegrass could negatively impact the grass-endophyte association and vice versa. Both endophyte and plant characters were measured under controlled environment and field conditions.ResultsExpected relative increases in total fatty acids of 17–58% accrued as a result of DGAT + CO expression with no significant difference between the endophyte-infected and non-infected progeny. Hyphal growth in association with DGAT + CO expression appeared normal when compared to control plants in a growth chamber. There was no significant difference in mycelial biomass for both strains AR1 and AR37, however, Epichloë-derived alkaloid concentrations were significantly lower on some occasions in the DGAT + CO plants compared to the corresponding null-segregant progenies, although these remained within the reported range for bioactivity.ConclusionsThese results suggest that the mutualistic association formed between perennial ryegrass and selected Epichloë strains does not influence expression of the host DGAT + CO technology, but that endophyte performance may be reduced under some circumstances. Further investigation will now be required to determine the preferred genetic backgrounds for introgression of the DGAT + CO trait in combination with selected endophyte strains, as grass host genetics is a major determinant to the success of the grass-endophyte association in this species.

The outlook for control of New Zealand’s most abundant, widespread and damaging invertebrate pests: social wasps

Invasive social wasps (Vespula germanica and V. vulgaris) are probably the most damaging, widespread invertebrate pests in New Zealand. In large areas of beech forests they can attain a biomass as great as, or greater than, the combined biomasses of birds, rodents and stoats. Wasps are effective and voracious predators and pose a significant risk to human health. Here, we highlight the scale and diversity of wasp impacts and the opportunities to develop cost effective landscape-scale tools for wasp control. Toxic baits can be extremely effective for wasp control, though the most effective pesticide (fipronil) is currently not commercially available for wasp control within New Zealand. Significant progress has been made to enhance lures for toxin delivery, including the use of synthetic lures. Biological control could offer the possibility of controlling wasps over huge areas at reasonable cost, though previous releases of biocontrol agents have not been successful. Avenues for further biological control work, such as the use of pathogens or parasitoids, are encouraged. We believe it is necessary and strategic to develop a suite of control tools. We urge government and the public to take action to control the wasp problem and to designate one agency as having the prime responsibility for doing this. Given that wasps are harming our natural heritage and inhibiting or adversely affecting people’s enjoyment of natural areas, we look to the natural resource sector to drive research and implement solutions. This includes Department of Conservation, Ministry of Primary Industry and Councils.

Genetic diversity of RNA viruses infecting invertebrate pests of rice.

Invertebrate species are a natural reservoir of viral genetic diversity, and invertebrate pests are widely distributed in crop fields. However, information on viruses infecting invertebrate pests of crops is limited. In this report, we describe the deep metatranscriptomic sequencing of 88 invertebrate samples covering all major invertebrate pests in rice fields. We identified 296 new RNA viruses and 13 known RNA viruses. These viruses clustered within 31 families, with many highly divergent viruses constituting potentially new families and genera. Of the identified viruses, 13 RNA viruses clustered within the Fiersviridae family of bacteriophages, and 48 RNA viruses clustered within families and genera of mycoviruses. We detected known rice viruses in novel invertebrate hosts at high abundances. Furthermore, some novel RNA viruses have genome structures closely matching to known plant viruses and clustered within genera of several plant virus species. Forty-five potential insect pathogenic RNA viruses were detected in invertebrate species. Our analysis revealed that host taxonomy plays a major role and geographical location plays an important role in structuring viral diversity. Cross-species transmission of RNA viruses was detected between invertebrate hosts. Newly identified viral genomes showed extensive variation for invertebrate viral families or genera. Together, the large-scale metatranscriptomic analysis greatly expands our understanding of RNA viruses in rice invertebrate species, the results provide valuable information for developing efficient strategies to manage insect pests and virus-mediated crop diseases.

The application of allelopathy in integrated pest management systems to control temperate European crop pests: a systematic map

BackgroundPesticides perform vital roles within agriculture but growing concern for their impact on the environment and non-target organisms has created a market for biopesticides with fewer ecological impacts. One source of biopesticides is allelochemicals, here defined as compounds released by an organism that have an inhibitory or stimulatory effect on neighbouring organisms. The focus of this study is allelopathic plants and their inhibitory effects on invertebrate herbivorous agricultural pests of temperate Europe. A systematic map is required to describe the current state of research and collate evidence.MethodsTwo academic databases were searched for relevant studies in temperate climates. The results were imported into EPPI-Reviewer, duplicates removed, studies screened and data extracted into a searchable database following the inclusion criteria and coding tool set out in the protocol. Screening consistency was checked at each stage using 5% of the studies. Critical appraisal was not conducted. Each unique combination of key variables (pest, plant, allelochemical, application method, intervention form) was treated as a separate datapoint or experiment. The data was then analysed and cross-tabulated to produce descriptive statistics and heatmaps.ResultsThis systematic map produced a database which included 243 studies containing 717 experiments from 5550 initial results. Research was unevenly distributed among all key variables with a distinct bias towards extracted allelochemical experiments under laboratory conditions. Allyl isothiocyanate was the most studied allelochemical and of the 99 identified chemical groups, flavonoids and glucosinolates were the most frequent. A wide range of pest and plant species were identified. Brassicas were the most studied plant family and Lepidoptera the most studied pest order. Physical living plants, as opposed to plant extracts or isolated allelochemicals, were predominantly studied in terms of resistance. Allelopathy application methods were not specified in the abstract of 22% of experiments and only 10% of experiments were conducted under field conditions.ConclusionAllelopathy has been studied in the context of temperate invertebrate pest control in some breadth but little depth and key pest species have not been targeted. The map highlighted significant gaps in the evidence base and a distinct lack of field studies or studies comparing application methods. It contains insufficient evidence to guide policy or management decisions, but provides a research tool and indicates areas for future studies including highlighting topics for secondary research. Critical appraisal is needed to determine allelopathic affect and future search strings should detail all application methods.Protocol registrationThe a-priori protocol was peer-reviewed and published through PROCEED (Kiely C, Randall N. Collaboration for Environmental Evidence: PROCEED. How have allelopathic plants been used within integrated pest management systems to control European crop pests in arable and field vegetable systems in temperate climates?: A Systematic Map Protocol. 2022. https://www.proceedevidence.info/protocol/view-result?id=14. Accessed 5 Jan 2023.).

Effects of macrocyclic lactone anthelmintics on seed germination of temperate grassland species.

Macrocyclic lactone anthelmintics are widely used to control invertebrate pests in livestock, such as sheep. While anthelmintic effects on non-target animals, such as dung-dwelling insects, are well studied, effects on seed germination are largely unknown. Seeds can come into contact with anthelmintics either during passage through the gastro-intestinal tract of grazing animals or when anthelmintics are excreted with their dung into the environment, which may result in changed germination patterns. We used four commonly applied macrocyclic lactones to assess their effects on germination: moxidectin, ivermectin, abamectin and doramectin as pure substances; moxidectin and ivermectin also in formulated form. We tested these pharmaceuticals on 17 different temperate grassland species from five plant families. Seeds were exposed to three concentrations of macrocyclic lactones (0.1, 1.0 and 10.0 mg·l-1 ) under controlled conditions, and germination was assessed over a 6-week period. From these data, we calculated germination percentage, mean germination time and germination synchrony. Most of the tested species were significantly affected in germination percentage and/or mean germination time by at least one of the tested pharmaceuticals, with formulated moxidectin having the largest impact. In general, the effects found were species- and pharmaceutical-specific. While formulated substances generally reduced germination percentage and increased mean germination time, pure substances increased germination percentage. Synchrony showed less clear patterns in all pharmaceuticals. Although effect size and sign varied between species, our study shows that non-target effects of macrocyclic lactones commonly occur in terrestrial plants. This may impede successful seed exchange between habitats via sheep, and even translate into profound changes to grazed ecosystems.

Increasing landscape heterogeneity as a win–win solution to manage trade-offs in biological control of crop and woodland pests

Agriculture and forestry cover more than 75% of Europe, and invertebrate pests are a costly challenge for these two economic sectors. Landscape management is increasingly promoted as a solution to enhance biological pest control, but little is known on its effects on adjacent crop fields and woodlands. This study aims to explore the effect of the proportion of woodlands and permanent grasslands as well as crop diversity on biological pest control simultaneously in cereals fields and woodland patches, in south-western France. We used different types of sentinel prey as well as bird and carabid community metrics to assess biological pest control potential in these two ecosystems. We first show that land cover variables influence biological pest control both in cereal fields and woodland patches, but have antagonistic effects in the two ecosystems. Although results vary according to the biological control indicator considered, we show that increasing landscape heterogeneity represents a valuable solution to manage trade-offs and promote higher average predation rates across forests and cereal fields. Our study therefore calls for more integrative studies to identify landscape management strategies that enable nature-based solutions across ecosystems.

Overexpression of Brassica napus COMT1 in Arabidopsis heightens UV-B-mediated resistance to Plutella xylostella herbivory.

UV-B radiation regulates numerous morphogenic, biochemical and physiological responses in plants, and can stimulate some responses typically associated with other abiotic and biotic stimuli, including invertebrate herbivory. Removal of UV-B from the growing environment of various plant species has been found to increase their susceptibility to consumption by invertebrate pests, however, to date, little research has been conducted to investigate the effects of UV-B on crop susceptibility to field pests. Here, we report findings from a multi-omic and genetic-based study investigating the mechanisms of UV-B-stimulated resistance of the crop, Brassica napus (oilseed rape), to herbivory from an economically important lepidopteran specialist of the Brassicaceae, Plutella xylostella (diamondback moth). The UV-B photoreceptor, UV RESISTANCE LOCUS 8 (UVR8), was not found to mediate resistance to this pest. RNA-Seq and untargeted metabolomics identified components of the sinapate/lignin biosynthetic pathway that were similarly regulated by UV-B and herbivory. Arabidopsis mutants in genes encoding two enzymes in the sinapate/lignin biosynthetic pathway, CAFFEATE O-METHYLTRANSFERASE 1 (COMT1) and ELICITOR-ACTIVATED GENE 3-2 (ELI3-2), retained UV-B-mediated resistance to P. xylostella herbivory. However, the overexpression of B. napus COMT1 in Arabidopsis further reduced plant susceptibility to P. xylostella herbivory in a UV-B-dependent manner. These findings demonstrate that overexpression of a component of the sinapate/lignin biosynthetic pathway in a member of the Brassicaceae can enhance UV-B-stimulated resistance to herbivory from P. xylostella.

External and gastrointestinal parasites of the black-faced ibis Theristicus melanopis (Pelecaniformes: Threskiornithidae) in the Los Ríos region, southern Chile.

The black-faced ibis, Theristicus melanopis, is considered a useful bird species for agricultural activity because it preys upon various invertebrate and vertebrate pests. Although it is a common species in Chile, limited information is available regarding its parasites. The main objective of this study was to recover the diversity of ectoparasites and gastrointestinal helminths in black-faced ibises living in the communes of Valdivia and Panguipulli, Los Ríos region. A total of 74 specimens were received for examination from the Centro de Rehabilitación de Fauna Silvestre at the Universidad Austral de Chile (CEREFAS-UACh), Valdivia, in 2011-2015. Black-faced ibises were externally inspected for ectoparasites by direct examining of the plumage, and necropsies were performed to examine digestive and respiratory organs in search of endoparasites. For each taxon, prevalence, mean intensity, mean abundance, and range of parasites per bird were estimated. Five species of ectoparasites and six species of helminths were identified. A total of 298 lice (Insecta: Phthiraptera) belonging to four species were collected: Ardeicola melanopis (13.51%), Colpocephalum trispinum (20.27%), Ibidoecus fissisignatus (4.05%), and Plegadiphilus mamillatus (9.46%). In addition, one feather mite species, Diodochaetus melanopis (Acari: Pterolichoidea) (17.56%), was isolated. In 48 black-faced ibis (64.86%), a total of 1229 gastrointestinal helminths were found: two nematodes, Porrocaecum heteropterum (55.41%) and Baruscapillaria obsignata (24.32%); one tapeworm Eugonodaeum nasuta (20.27%); two digeneans, Echinoparyphium recurvatum (1.35%) and Strigea bulbosa (6.76%); and the acanthocephalan Sphaerirostris sp. (1.35%). The findings of the following parasites present new host-parasite associations: P. mamillatus, D. melanopis, B. obsignata, E. recurvatum, S. bulbosa, and Sphaerirostris sp. Additionally, the louse P. mamillatus, feather mite D. melanopis, platyhelminths E. nasuta, E. recurvatum and S. bulbosa, and the acanthocephalan Sphaerirostris sp. are new records for the fauna of Chile.

The impact of field margins on biological pest control: a meta-analysis

Floral field margins are known to benefit invertebrate species diversity and abundance within agricultural landscapes, but variation in success limits widespread uptake. Understanding how variation within floral field margins can affect certain entomological groupings is lacking but would allow for a more individualised design of margins to enhance biological control. This meta-analysis aims to answer the question; do floral field margins benefit biological pest control over grassy field margins? We found that floral margins significantly benefit the natural enemy community and biological control services, relative to non-floral grass margins. We confirm that field margin type is linked to higher abundance and diversity of natural enemies, lower numbers of herbivorous invertebrate pests, and reduced crop damage. We consider whether specific characterisations of natural enemies and pest communities vary between these margin types, finding key differences in the abundances of aerial and epigeal enemies, the diversity of parasitoid and predatory enemies and pest abundances found in naturally regenerating and sown floral field margins. The finding here cements the implementation of floral field margins as a legitimate control method for crop pests in the face of losses due to pesticides and highlights design and management considerations for the success of floral margins.

Exploiting volatile organic compounds in crop protection: A systematic review of 1‐octen‐3‐ol and 3‐octanone

AbstractThe 21st century has brought new challenges to the agri‐food industry due to population growth, global warming, and greater public awareness of environmental issues. Ensuring global food security for future generations is crucial. However, pests, weeds, and diseases still significantly contribute to crop losses, and the availability of effective conventional synthetic pesticides is decreasing. To address this, new and diverse pest management tools are needed. One pest management tool showing potential for invertebrate pest management is the exploitation of volatile organic compounds (VOCs)—in particular, the compounds 1‐octen‐3‐ol and 3‐octanone. This review aims to explore the extent to which 1‐octen‐3‐ol and 3‐octanone show potential in the future management of invertebrate crop and animal pests. A significant increase in the rate of publication of literature on the use of 1‐octen‐3‐ol and 3‐octanone in crop protection since 2018 is identified by this review, therefore, showing the potential importance of these compounds for use in future pest management. This review also identifies key interactions between naturally occurring biosynthesised 1‐octen‐3‐ol and 3‐octanone, and a range of invertebrate targets. Many of these interactions with key crop pests are sourced from the taxonomic families Lamiaceae, Fabaceae, and Trichomaceae. However, analysis of the practical application of these sources in an integrated pest management programme identifies clear limitations with the use of naturally occurring biosynthesised 1‐octen‐3‐ol and 3‐octanone. Rather, future focus should be placed on the development and exploitation of synthesised nature identical 1‐octen‐3‐ol and 3‐octanone for use as a biopesticide product. Overall, 1‐octen‐3‐ol and 3‐octanone show potential for exploitation in future crop protection, being abundant in source and diversity of invertebrate interactions. However, their use as a naturally occurring biosynthesised chemical is likely not practical for direct implementation in crop protection. Rather, focus should be placed on the development and exploitation of synthesised nature identical variants of these compounds for use as a biopesticide.

Behavioral response of three subterranean pests (Agriotes lineatus, Diabrotica virgifera virgifera, Phyllopertha horticola) to the fungal volatile organic compounds 1-octen-3-ol and 3-octanone

The volatile organic compounds (VOCs) 1-octen-3-ol and 3-octanone produced by the entomopathogenic fungus Metarhizium brunneum are known to have pesticidal properties at high doses against a range of invertebrate pests. Very little is known about their behavior-modifying (semiochemical) properties. This study focused on investigating the behavioral responses of three subterranean crop pests, wireworm (Agriotes lineatus), western corn rootworm (Diabrotica virgifera virgifera), and garden chafer (Phyllopertha horticola), to relatively low doses of 1-octen-3-ol and 3-octanone. The behavior of wireworms and corn rootworms were slightly influenced by the VOCs, yet not significantly. Western corn rootworms appeared to be slightly attracted by 100 µl and 200 µl 1-octen-3-ol and 100 µl dose of 3-octanone, respectively but slightly repelled by the higher dose of 3-octanone. Wireworms appeared to be slightly repelled by 1-octen-3-ol and high dose 3-octanone, but slightly attracted by the 100 µl dose of 3-octanone. The VOCs had no significant impact on garden chafer. In silico studies showed that corn rootworm odorant binding proteins (OBPs) had a strong binding affinity of 1-octen-3-ol and high dose 3-octanone, indicating that these VOCs can be detected and recognized by corn rootworm. OBPs are well conserved between species; thus, wireworm and garden chafer OBPs should also be able to bind with the VOCs. Further trials will be done to confirm that VOCs could be used as semiochemicals. Appropriate formulation of the VOCs should increase their efficacy and prevent rapid dissipation of the VOCs.

Insecticidal activity of Bacillus thuringiensis towards Agrotis exclamationis larvae-A widespread and underestimated pest of the Palearctic zone.

acillus thuringiensis is an entomopathogenic bacterium commonly used as a bioinsecticide against numerous invertebrate pests. However, the efficacy of this microbe has not yet been determined towards Agrotis exclamationis-a lepidopteran, polyphagous pest, widespread throughout the Palearctic zone. In this work we have detected very low susceptibility of A. exclamationis to B. thuringiensis commercial strains, used as microbial formulations in pest control. To investigate this matter, the biological activity of six selected (Cry1Aa, Cry1Ca, Cry1Ia, Cry2Ab, Cry9Ea and Vip3Aa), heterogously-expressed Bacillus thuringiensis insecticidal proteins has been assessed towards A. exclamationis. Only Cry9Ea and Vip3Aa caused significant mortality in the tested pest species, with LC50 values of 950 and 140 ng/cm2, respectively. The histopathological effects of Cry9Ea and Vip3Aa on A. exclamationis were determined. On the other hand, Cry1- and Cry2-type toxins, which are the main active molecules of the majority of currently-used B. thuringiensis-based biocontrol agents (including the commercial strains tested in this work), did not cause mortality in target insect, but only different levels of growth inhibition. Moreover, in the case of Cry1Ca and Cry1Ia hormesis has been observed-a phenomenon that may be disadvantageous in implementation of these proteins in pest management. The obtained results broaden the existing knowledge regarding B. thuringiensis insecticidal protein target range and depict variable susceptibility of A. exclamationis to different groups of Cry/Vip toxins. This work indicates Cry9Ea and Vip3Aa as good candidates for efficient biological control of A. exclamationis and possibly other Agrotinae and discusses the potential use of Vip3-type and Cry9-type insecticidal proteins as successful bioinsecticides.

KASP genotyping and semi-quantitation of G275E mutation in the α6 subunit of Thrips palmi nAChR gene conferring spinetoram resistance.

Pesticide resistance is a long-standing and growing problem in the chemical control of invertebrate pests. Molecular diagnostic methods can facilitate pesticide resistance management by accurately and efficiently detecting resistant mutations and their frequency. In this study, the kompetitive allele specific PCR (KASP) approach, a technology for high-throughput single nucleotide polymorphism (SNP) genotyping, is validated as a useful method for characterizing genotypes at a pesticide-resistance locus for the first time. We focus on the spinetoram resistance mutation of G275E in the nicotinic acetylcholine receptor alpha 6 (nAChR α6) subunit gene of Thrips palmi. Of the 341 individuals of Thrips palmi tested, 98.24% were successfully genotyped, with 100% concordance with Sanger sequencing results. We then quantitatively mixed genomic DNA of known genotypes to establish 21 DNA mixtures with a resistant allele frequency ranging from 0 to 100% at steps of 5%. The linear discriminant analysis (LDA) showed that 75.8% of original grouped cases were correctly classified; six groups had no overlap in membership (resistant allele frequency: 0%, 5%, 10-75%, 80-85%, 90-95%, and 100%). When we chose 11 pooled samples with 10% steps for LDA, 84.4% of original grouped cases were correctly classified; seven groups had no overlap in membership (0%, 10%, 20-30%, 40-70%, 80%, 90%, 100%). The results indicated that KASP applied to pooled samples may provide a semi-quantitative estimate of resistance. Our study points to the suitability of KASP for high-throughput genotyping of genotypes affecting pesticide resistance and semi-quantitative assessments of resistance allele frequencies in populations. © 2023 Society of Chemical Industry.

Multiple S-Layer Proteins of Brevibacillus laterosporus as Virulence Factors against Insects.

S-layers are involved in the adaptation of bacteria to the outside environment and in pathogenesis, often representing special virulence factors. Vegetative cells of the entomopathogenic bacterium Brevibacillus laterosporus are characterized by an overproduction of extracellular surface layers that are released in the medium during growth. The purpose of this study was to characterize cell wall proteins of this bacterium and to investigate their involvement in pathogenesis. Electron microscopy observations documented the presence of multiple S-layers, including an outermost (OW) and a middle (MW) layer, in addition to the peptidoglycan layer covering the plasma membrane. After identifying these proteins (OWP and MWP) by mass spectrometry analyses, and determining their gene sequences, the cell wall multilayer-released fraction was successfully isolated and used in insect bioassays alone and in combination with bacterial spores. This study confirmed a central role of spores in bacterial pathogenicity to insects but also detected a significant virulence associated with fractions containing released cell wall multilayer proteins. Taken together, S-layer proteins appear to be part of the toxins and virulence factors complex of this microbial control agent of invertebrate pests.

Crop protection practices and risks associated with human fungal infectious diseases: a One Health perspective

We review interactions between crop protection practices (developed to control plant pathogens and invertebrate pests) and human fungal infectious diseases. Unlike viral, bacterial and parasitic infections, fungal infections in humans are usually only superficial in healthy individuals, but can become invasive and pose serious risks to immunosuppressed individuals. Although their global impact is less than that of other infectious diseases, human fungal infections still pose serious public health issues. For instance, the use of synthetic agricultural fungicides, particularly the azole class, under conventional intensive, or efficiency improvement-based crop protection practices, is at risk as far as antimicrobial resistance is concerned, due to cases of cross-resistance to clinical azoles used to treat pulmonary aspergillosis, candidiasis and cryptococcocis. In this respect, the One Health approach, originally designed for other types of human pathogens, looks relevant for human pathogenic fungi. Additionally, some entomopathogenic fungi used as biocontrol products against crop pests in a substitution-based approach, may be potentially pathogenic to humans. Very few examples of redesign-based practices (i.e. Agroecological Crop Protection) emerged from our analysis on human fungal diseases. However, discontinuing agricultural azole fungicides (as practiced on organic farms, and which may to some extent be related to the redesign strategy) appears to be the best way to reduce selection pressure and hence the level of azole-resistant human pathogenic fungal strains in the environment.