Pest Species Research Articles

Characterisation of the bacteriomes harboured by major wireworm pest species in the Canadian Prairies.

Nearly all insects harbour bacterial communities that can have a profound effect on their life history, including regulating and shaping host metabolism, development, immunity and fitness. The bacteriomes of several coleopterans have been described; however, very little has been reported for wireworms. These long-lived larvae of click beetles (Coleoptera: Elateridae) are major agricultural pests of a variety of crops grown in the Canadian Prairies. Consequently, the goal of this study was to characterise the bacteriomes of five of the most significant pest species within the region: Limonius californicus, Hypnoidus abbreviatus, H. bicolor, Aeolus mellillus and Dalopius spp. To do this, we collected larvae from southern Manitoba fields (pre-seeding) and carried out 16S rRNA sequencing on individual specimens. Our results indicate wireworms have diverse and taxon-rich bacterial communities, with over 400 genera identified predominately from the phyla Proteobacteria, Actinobacteriota, Bacteroidota and Firmicutes. However, each species had nine or fewer genera comprising >80% of their bacteriome. Network analyses revealed some community structuring consistent among species, which may culminate in shaping/regulating host biology. Moreover, the microbial signatures were influenced by both ontogeny (early vs. late stage larvae) and reproductive strategy (sexual vs. parthenogenetic), with a myriad of other factors likely contributing to bacterial diversity that are impossible to resolve from our study. Overall, this metagenomics study represents the first to characterise the bacteriomes of wireworms in the Canadian Prairies and the findings could assist in the development of sustainable management strategies for these important agricultural pests.

Marking Helicoverpa zea (Lepidoptera: Noctuidae) with fluorophores for use in mark-release-recapture research

Abstract Knowledge of insect dispersal and long-distance migratory flight capacity and patterns represent key factors needed for risk assessment of invasive pest species, insecticide resistance management, and more effective pest control. Having operative tools to both mark and track insect pest movement is therefore critical to achieving such goals. Here, we describe a new procedure for marking Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), one of the most economically important crop pests in the United States. Adult H. zea moths were effectively marked using the liquid fluorophore cartax green, a persistent UV-fluorescent pigment, both directly by topical application and indirectly by briefly submerging pupae in the marking solution prior to adult emergence. Regardless of the application method, the cartax mark was retained on the moths throughout their entire adult lifespan. No mortality differences were observed between cartax green-marked and water-marked (control) moths. Additionally, using rotary flight mills, we found no significant differences in several flight parameters, including total number of flights, flight speeds, flight distances, or flight durations between unmarked and cartax-marked moths. Under laboratory conditions, we did observe the lateral transfer of different colored fluorophores between moths, indicating that undesirable marking could potentially occur. Moreover, we found that not all fluorophores were equally retained on H. zea moths, with cartax green remaining intact on moths longer than did a corresponding magenta fluorophore. The results show that cartax green fluorophore could be a practical marker for H. zea and other holometabolous species targeted for large-scale mark-release-recapture research.

Climate change is likely to favour polyvoltine and invasive insect species, leading to more damage in the mid-latitude vineyards of Neuchatel

Climate change has major impacts on viticultural ecosystems worldwide, affecting wine production. Apart from direct impacts, the increase in temperature during the development season is likely to favour insect species, including polyvoltine ones, leading potentially to more damage in the vineyards. In this study, we examined the extent to which changes in mean temperature over the development season (March through September) can potentially increase the voltinism change the phenology and influence the reproduction of pest species in the vineyard area of Neuchatel (Switzerland). We first analysed long-term daily mean temperature data from 1970 to 2022 at the meteorological station of Neuchâtel. Then we used two climate scenarios (RCP4.5 and RCP8.5) to analyse daily mean temperature during the period 2023–2099. For both of these periods, we computed the number of growing degree days (GDDs) above 10 °C, as it is the base development temperature for many polyvoltine pest species. We then used specific bioclimatic models for two major pest species, namely the European grapevine moth (Lobesia botrana) and the American grapevine leafhopper (Scaphoideus titanus) to compare the current and future suitability of these two species to the air temperature conditions in Neuchâtel. Our results show an increase of about 425 GDDs since 1970 (+85 GDDs per decade). According to our models, values will continue to rise during the next decades, with a trend ranging from +28 GDDs per decade (RCP4.5) to +100 GDDs per decade (RCP8.5). This could lead to additional generations of polyvoltine pest species. A third annual generation can be expected in one year out of four for the European grapevine moth by the middle of the 21st century. While temperature conditions are currently moderately favourable for the American grapevine leafhopper, they are predicted to become highly favourable by the middle and the end of the century under both scenarios. These trends mean that climate change is likely to increase pest damage risks in the vineyards of Neuchatel in the future. Pest regulation will remain crucial in limiting major impacts on wine production.

Trap colour strongly affects the ability of deep learning models to recognize insect species in images of sticky traps.

The use of computer vision and deep learning models to automatically classify insect species on sticky traps has proven to be a cost- and time-efficient approach to pest monitoring. As different species are attracted to different colours, the variety of sticky trap colours poses a challenge to the performance of the models. However, the effectiveness of deep learning in classifying pests on different coloured sticky traps has not yet been sufficiently explored. In this study, we aim to investigate the influence of sticky trap colour and imaging devices on the performance of deep learning models in classifying pests on sticky traps. Our results show that using the MobileNetV2 architecture with transparent sticky traps as training data, the model predicted the pest species on transparent sticky traps with an accuracy of at least 0.95 and on other sticky trap colours with at least 0.85 of the F1 score. Using a generalised linear model (GLM) and a Boruta feature selection algorithm, we also showed that the colour and architecture of the sticky traps significantly influenced the performance of the model. Our results support the development of an automatic classification of pests on a sticky trap, which should focus on colour and deep learning architecture to achieve good results. Future studies could aim to incorporate the trap system into pest monitoring, providing more accurate and cost-effective results in a pest management programme. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

How do global forest pests respond to increasing temperatures? – a meta‐analysis

Biotic disturbances caused by insects and pathogens have a major impact on forests in the Northern Hemisphere. Knowledge of the effects of increasing temperature on the performance of these forest pests will thus be crucial for predicting future disturbance risks. Here, we systematically review the direct effects of increasing temperatures on four functional subgroups of forest pests, including leaf chewers, sap suckers, bark and wood borers, and pathogens. We considered 118 studies (2003–2022) representing 72 pest species feeding on 33 host genera from sub‐tropical, temperate and boreal forests in Asia, Europe and North America. Based on a subset of 89 studies reporting the required data, we conducted a meta‐analysis 1) distinguishing the functional subgroups, and 2) considering the main life‐history traits, i.e. development, fitness and survival. A temperature corresponding to the expected mean temperature during the growing season in the years 2081–2100 had a significant positive effect on the overall performance of leaf chewers (+18%) and bark and wood borers (+10%), while sap suckers and pathogens remained unaffected. In contrast, performance was not or even significantly negatively affected when a more pronounced temperature increase, i.e. corresponding to the temperature maxima in 2081–2100, was considered. This finding reflects the non‐linear temperature–performance relationship beyond currently evolved temperature optima in insects and pathogens. Furthermore, we showed that differential responses of life‐history traits to increased temperatures may counterbalance each other (e.g. development versus survival), highlighting the importance of a multi‐trait approach to assessing the impact of global warming on pest performance. By quantifying the effects of increasing temperatures on forest pest performance, our results facilitate the prediction of biotic disturbance impacts in a future climate. For instance, they could provide a valuable contribution to the parameterization of large‐scale ecosystem models, which often do not explicitly consider the response of biotic disturbances to climate change.

Entomopathogenic potential of indigenous Simplicillium subtropicum (Hypocreales: Cordycipitaceae) isolates from Tamil Nadu, India, against the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae)

BackgroundAphis gossypii Glover (Hemiptera: Aphididae) is an economically important polyphagous pest species infesting many agricultural and horticultural crops causing severe yield losses. In order to develop biopesticides for the management of aphids in an environmentally safe manner, 6 indigenous entomopathogenic fungi Simplicillium subtropicum were isolated from soils of Tamil Nadu and their pathogenicity was tested against A. gossypii under laboratory conditions after characterization.ResultsPhenotypic and molecular characterization was performed for all the isolates for species identification. Results of the pathogenicity test showed that the isolate S6 (PP446637) performed well among other isolates causing 58.33% mortality on 7 days after treatment (DAT) @ 1 × 108 spores/ml. The LC50 and LT50 values were found to be 2.36 × 107 spores/ml at 7 DAT and 160.20 h @ 1 × 108 spores/ml, respectively. SEM images of A. gossypii treated with the isolate S6 (PP446637) revealed that initial phase of infection, i.e., adhesion, formation of germ tube and appressoria starts within 24 h post-infection (hpi), hyphal development and penetration of cuticle occurred within 48 hpi and extrusion of mycelium and conidiogenesis occurred within 72 hpi.ConclusionThis study reveals the entomopathogenic potential of indigenous S. subtropicum isolates against A. gossypii and suggests their use for the eco-friendly management of aphids.

Using a conditioned place preference assay in fruit flies to examine effects of insecticidal compounds on contextual memory

Insecticides are vital for safeguarding agricultural crops against pests, albeit many lack selectivity towards pest species and are poorly bio-degradable. This leads to targeting of beneficial organisms like pollinators and widespread environmental contamination of soil and water. Exposure to insecticides such as neonicotinoids causes insect paralysis and mortality at higher doses, while sublethal doses can disrupt other functions that are crucial for survival such as learning and memory performance. Potent and selective arachnid venom peptides affecting a variety of molecular targets are being explored as bioinsecticide candidates. However, their effect on insect learning is poorly understood. We therefore established a sucrose-induced conditioned place preference (CPP) assay using Drosophila melanogaster fruit flies to provide a means of evaluating how various classes of insecticidal compounds interact with insect memory to assess their broader ecological consequences. Our results confirmed the adverse effect of a sublethal dose of the neonicotinoid insecticide imidacloprid (20 pg/fly) on fly CPP formation upon daily injection during the conditioning phase. However, imidacloprid did not affect CPP retrieval when applied after the conditioning phase. Sublethal doses of the two insecticidal spider venom peptides μ-DGTX-Dc1a (Dc1a; 70 pg/fly) and U1-AGTX-Ta1a (Ta1a; 125 pg/fly) had no effect on either CPP formation or retrieval, underlining their potential as novel and safe bioinsecticide candidates.

Identifying insect predators using camera traps reveal unexpected predator communities in oilseed rape fields

Cameras are common tools for ecologists studying species abundance, richness, and interactions. They are mainly used to study large animals but are increasingly used to study invertebrates. Camera traps could be a powerful tool to identify and quantify the natural enemies, such as predators, of specific agricultural pests. This knowledge can then be applied to adapt farming practices to favour the predators identified and improve conservation biocontrol.Here, cameras were used to identify predators of two insect pests of oilseed rape (Brassica napus): the pollen beetle (Brassicogethes aeneus) and the brassica pod midge (Dasineura brassicae). These insects are spring pests of oilseed rape and are both susceptible to predation by ground-dwelling arthropods during their development cycle. The objectives of this study were to 1) identify the predators of the pest species, and 2) investigate the hypothesis that the diel activity periods of the predators match the timing of pest larval presence on the ground. Field observations were conducted in two locations over two consecutive years in the UK.In contrast to previous reports, our data collected using cameras showed that larval stages of predatory beetles are responsible for most of the predation events and that adult stages were not frequently observed feeding on the prey. Our data also showed that the traditional method, using pitfall traps, failed to detect the presence of large numbers of beetle larvae. Interestingly, the pests dropped to the ground and were therefore most susceptible to predation at the time when predators were most active.These results give new insight on the predators of the two most important spring pests of oilseed rape in Europe. This knowledge can be used by practitioners to develop framing practices targeted on enhancing the abundance of the larval stages of these beneficial arthropods to better control the pests in a more sustainable way.

Do Sex Ratio Distorting Microbes Inhibit the Evolution of Pesticide Resistance? An Experimental Test.

We are still largely reliant on pesticides for the suppression of arthropod pests which threaten human health and food production, but the recent rise of evolved resistance among important pest species has reduced pesticide efficacy. Despite this, our understanding of strategies that effectively limit the evolution of resistance remains weak. Male-killing sex ratio distorting microbes (SRDMs), such as Wolbachia and Spiroplasma, are common among arthropod species. Previous theoretical work has suggested that they could limit adaptive potential in two ways: first, because by distorting sex ratios they reduce the effective population size, and second, because infected females produce no male offspring which restricts gene flow. Here we present the results of a novel experiment in which we test the extent by which these two mechanisms limit the adaptive response of arthropods to pesticide. Using a fully factorial design, we manipulated the adult sex ratio of laboratory populations of Drosophila melanogaster, both in the presence and absence of SRDMs, and exposed these populations to six generations of pesticide poisoning. This design allows the effects of SRDMs on sex ratio and their effects on gene flow to be estimated separately. After six generations, individuals from populations with even sex ratios displayed a higher resistance to pesticide relative to individuals from female-biased populations. By contrast, we found no effect of the presence of SRDMs in host populations on pesticide resistance independent of sex ratio. In addition, males were more susceptible to pesticide than females-this was true of flies from both naïve and previously exposed populations. These findings provide the first empirical proof of concept that sex ratio distortion arising from SRDMs can limit adaptation to pesticides, but cast doubt on the theoretical effect of male-killers limiting adaptation by disrupting gene flow.

Warmer is better for evolutionary rescue, driving a warm-to-cold bias in habitat colonization dynamics.

Evolutionary rescue occurs when populations survive lethal environmental stresses through the rising and fixation of tolerant genotypes. Temperature has long been believed to determine the evolutionary speed of populations and species. Here, we suggest that warmer temperatures can facilitate evolutionary rescue. Moreover, with dispersal among habitats, the advantage in evolutionary rescue for warmer populations may cause a bias in habitat colonization dynamics towards the warm-to-cold direction. We experimentally tested these hypotheses with a model microbial system. Our first experiment showed that bacterial populations at warmer temperatures had a greater chance to evolve resistance and escape the fate of extinction under an antibiotic treatment. In the second experiment, metapopulations that consisted of warm and cold habitats were exposed to the antibiotic stress; local populations that went extinct might be recolonized, and such recolonization events were biased to the warm-to-cold direction. We also examined possible mechanisms underlying the temperature effect on the rapid evolution of resistance in our study system. Our results may help to understand the mechanisms of maintenance of biodiversity and patterns of gene flow among climatic regions, particularly in pest species subject to chemical control treatments.

Confirmation of the presence of Tipulia tipuliformis (Clerck, 1759) (Lepidoptera, Sesiidae) in the Crimea

The presence of the pest species Tipulia tipuliformis (Lepidoptera, Sesiidae) is confirmed in the Crimean Peninsula with the help of sex attractants in 10 localities.

Divergent Heat Stress Responses in Bactrocera tryoni and Ceratitis capitata.

Invasive Tephritid fruit flies rank among the most destructive agricultural and horticultural pests worldwide. Heat treatment is commonly employed as a post-harvest method to exterminate fruit flies in fruits or vegetables. These pest species exhibit distinct tolerance to heat treatments, suggesting that the molecular pathways affected by heat may differ among species. In this study, the Queensland fruit fly (Qfly), Bactrocera tryoni, was utilised as a model investigate its molecular response to heat stress through heat bioassays. RNA samples from flies before and after heat treatment were extracted and sequenced to identify genes with significant changes in expression. These findings were compared to another serious Tephritid fruit fly species, the Mediterranean fruit fly (Medfly), Ceratitis capitata, under similar heat treatment conditions. The analysis reveals only three common genes: heat shock protein 70 (HSP70), HSP68, and 14-3-3 zeta protein. However, despite these shared genes, their expression patterns differ between Qfly and Medfly. This suggests that these genes might play different roles in the heat responses of each species and could be regulated differently. This study presents the first evidence of differing molecular responses to heat between Qfly and Medfly, potentially linked to their varied origins, habitats, and genetic backgrounds. These findings offer new insights into Tephritid fruit fly responses to heat at the molecular level, which may help refine post-harvest strategies to control these pests in the future.

Influence of Height on the Abundance and Richness of Green Lacewings (Neuroptera: Chrysopidae) in an Anthropically Modified Habitat.

Investigation of the diversity of lacewings (Neuroptera: Chrysopidae) is crucial in agricultural systems, as these insects are important predators of many pest species. Recent studies have shown that height influences the abundance and richness of insects. Information on these factors is scarce for species of Chrysopidae at different heights in agricultural and forest environments. This study aimed to evaluate the influence of height on the abundance and richness of green lacewings in an anthropically modified environment. Multilure traps baited with putrescine and ammonium acetate were placed in four areas of the "Luiz de Queiroz" Campus (Piracicaba, São Paulo State, Brazil) at two heights (2 and 10m) from April 2019 to March 2020. Species captured in traps hung at 2 and 10m above the ground surface were studied with the faunistic analysis ANAFAU, using ecological parameters and diversity indices. The similarity between the species was measured using the Morisita-Horn coefficient. Thirteen species of Chrysopidae were captured, and more species and specimens of green lacewings were collected with the traps at 2m than at 10m, that is, height influenced the abundance and richness of the lacewing species. Leucochrysa (Nodita) cruentata (Schneider) was predominant in most areas studied. The highest diversity and abundance of green lacewings was observed on Areão farm in trap at 2m height. However, Ceraeochrysa claveri (Navás) and Ce. everes (Banks) showed a more similar ecological pattern. Multilure traps baited with putrescine and ammonium acetate were effective in sampling green lacewings, mainly at 2m height.

Potent and selective ‘genetic zipper’ method for DNA-programmable plant protection: innovative oligonucleotide insecticides against Trioza alacris Flor

Chemical insecticides increased the chemical burden on natural ecosystems posing environmental health risk factor. The urgent need for a more sustainable and ecological approach has produced many innovative ideas, including eco-friendly ‘genetic zipper’ method (or CUAD platform) based on contact oligonucleotide insecticides. Oligonucleotide insecticides have enjoyed success recently on many sternorrhynchans showing highly adaptable structure for distinct insect pest species and selective mode of action. In this article, we describe the efficiency of the oligonucleotide insecticides (briefly, olinscides or DNA insecticides) Alacris-11 and Laura-11, as well as their combined use in mixture (1:1), designed for control of bay sucker (Trioza alacris Flor), an important psyllid pest of noble laurel (Laurus nobilis L.). These olinscides are based on short unmodified antisense DNA oligonucleotides that target ITS2 between 5.8S rRNA and 28S rRNA in pre-rRNA (Laura-11) and 28S rRNA region in mature 28S rRNA and pre-rRNA (Alacris-11). The maximum pest mortality, observed on the 14th day of the experiment, comprised 95.01 ± 4.42% for Alacris-11, 97.16 ± 2.48% for Laura-11, and 98.72 ± 1.14% for their mixture (1:1). The control oligonucleotide CTGA-11 did not cause any significant mortality (9.38 ± 0.57%), emphasizing selectivity in the action of oligonucleotide insecticides. The results show potent and specific nature of oligonucleotide insecticides for pest control and open up new frontiers in control of economically important psyllids in agriculture and forestry, including Asian citrus psyllid (Diaphorina citri Kuwayama) and many others. Scientists can easily adopt ‘genetic zipper’ method for plethora of insect pests because DNA is a programmable molecule and provides game-changing characteristics for plant protection.Graphical

Checklist and key to species of stink bugs (Hemiptera, Heteroptera, Pentatomidae) of Kentucky, United States of America.

Stink bugs (Heteroptera: Pentatomidae) have received a lot of attention as there are many economically important pest species. However, the status of species richness, distribution, and taxonomy remain overlooked and outdated in Kentucky (USA). Having such information at a regional scale is crucial to allow the development of suitable pest management and conservation programs. Here, the stink bug fauna of Kentucky was examined from museum specimens, literature, and public online repositories. Overall, 42 species in 28 genera and three subfamilies (Asopinae, Podopinae, and Pentatominae) are listed from Kentucky. Thirteen species are new records for Kentucky, 10 species are considered to be of economic importance and eight are strict predators. Pictures of species are provided along with the first key for the identification of the stink bug species of Kentucky.

Can a Mixture of Farnesene Isomers Avert the Infestation of Aphids in Sugar Beet Crops?

The negative impact of pesticides on the environment and the potential of pest species to develop pesticide resistance make it necessary to explore new methods of pest control. Pheromones and other behavior-modifying semiochemicals are already important in integrated pest management (IPM). (E)-ß-farnesene (EBF) is a semiochemical that acts as an alarm pheromone in aphids. Upon perception of EBF, aphids stop feeding, move away, and sometimes even abandon the host plant. The aphids Myzus persicae and Aphis fabae are significant crop pests and vectors of many harmful phytopathogens affecting sugar beet (Beta vulgaris). Field trials were conducted at different locations in Germany to test whether dispensers containing a mixture of farnesene isomers (FIMs) including EBF were able to reduce the infestation of these species on sugar beet. Our results showed a reduction in aphid abundance in the FIM-treated patches in two out of three sites. Therefore, we hypothesize that FIM dispensers could prevent aphid infestation and could be used in combination with other IPM measures. However, more research is required to increase the effect and ensure the reliability of this method.

NURSERY PEST PROBLEMS ON Acacia mangium, Cinamomum cassia and Illicium verum IN BAC KAN PROVINCE, VIETNAM

Acacia mangium, Cinamomum cassia, and Illicium verum are pivotal forestry species in Bac Kan province, where they contribute significantly to economic and environmental welfare. A. mangium's wood is essential for the pulp industry, while C. cassia and I. verum provide essential oils with extensive industrial applications. Despite their economic value, increased plantation areas have exacerbated insect pest outbreaks, affecting tree growth and yield. However, the focus of previous research on insect pests has primarily been on plantations, leaving nursery infestations largely unexplored. This study aims to overcome this gap by investigating insect pest species diversity in nurseries in Bac Kan province. Field observations and standard plot surveys were conducted in Cho Moi district and Bac Kan city, resulting in the collection of 72 survey forms. The survey revealed significant insect pest species compositions in A. mangium, C. cassia, and I. verum nurseries. Notably, Helopeltis theivora was identified as the primary pest infesting young A. mangium trees, while Echinothrips sp. emerged as the main pest species in C. cassia nurseries, and others affected I. verum nurseries. These findings underscore the need for ongoing monitoring and research to develop effective pest management strategies. Such insights are crucial for sustaining the economic and environmental benefits of these forestry species in Bac Kan province.

Endophytic Bacteria and Fungi Associated with Polygonum cuspidatum in the Russian Far East.

Polygonum cuspidatum, alternatively known as Fallopia japonica or Reynoutria japonica, is a perennial herb belonging to the Polygonaceae family. Commonly called Japanese knotweed or Asian knotweed, this plant is native to East Asia, particularly in regions such as Korea, China, and Japan. It has successfully adapted to a wide range of habitats, resulting in it being listed as a pest and invasive species in several countries in North America and Europe. This study focuses on analysing the composition of the bacterial and fungal endophytic communities associated with Japanese knotweed growing in the Russian Far East, employing next-generation sequencing (NGS) and a cultivation-based method (microbiological sowing). The NGS analysis showed that the dominant classes of endophytic bacteria were Alphaproteobacteria (28%) and Gammaproteobacteria (28%), Actinobacteria (20%), Bacteroidia (15%), and Bacilli (4%), and fungal classes were Agaricomycetes (40%), Dothideomycetes (24%), Leotiomycetes (10%), Tremellomycetes (9%), Pezizomycetes (5%), Sordariomycetes (3%), and Exobasidiomycetes (3%). The most common genera of endophytic bacteria were Burkholderia-Caballeronia-Parabukholderia, Sphingomonas, Hydrotalea, Methylobacterium-Metylorubrum, Cutibacterium, and Comamonadaceae, and genera of fungal endophytes were Marasmius, Tuber, Microcyclosporella, Schizothyrium, Alternaria, Parastagonospora, Vishniacozyma, and Cladosporium. The present data showed that the roots, leaves, and stems of P. cuspidatum have a greater number and diversity of endophytic bacteria and fungi compared to the flowers and seeds. Thus, the biodiversity of endophytic bacteria and fungi of P. cuspidatum was described and analysed for the first time in this study.

Recent Advances in Biopesticide Research and Development: A Focus on Microbial: A Review

Biopesticides are pest control products derived from natural sources such as microbes, macro-organisms (insects and pathogens), plant extracts, and certain minerals. Many biopesticides are considered environmentally safe and can complement or substitute conventional chemical pesticides. They can also be highly specific or broad spectrum with a unique mode of action controlling a wide range of pest species. Due to their target-specificity and low to no environmental residuality, biopesticides conform to the 3 pillars of Climate-Smart Agriculture, the Sustainable Development Goals, and ultimately, the Paris Agreement. This review focuses largely on microbial biopesticides derived from fungi, bacteria, viruses, and nematodes. It discusses (i) the various microbial biopesticide formulations, (ii) the mode of microbial biopesticide action, (iii) the factors that affect the potential efficacy of biopesticides, (iv) challenges to the adoption of microbial biopesticides, and (v) the role of microbial biopesticides in Integrated Pest Management programs. Finally, advancements in application techniques, as well as future research directions and gaps are highlighted.

Modelling time-temperature-dependent mortality of pest flies in cold storage to support the management of trade-related biosecurity risks

AbstractCold treatment with rigorous regulatory oversight is often mandated to manage horticultural trade-related biosecurity threats, such as invasive, cold-sensitive fruit flies (Diptera: Tephritidae). Cold treatment schedules, developed through rigorous laboratory experiments, require a set temperature and duration to ensure at least a probit 8.7 (99.99%) mortality rate, regardless of infestation likelihood. This threshold is costly to demonstrate for each pest and commodity combination and the resultant treatment may be harmful to fruit quality. Moreover, these stringent schedules do not account for cold-induced mortality already occurring in commercial supply chains. We developed a predictive temperature-dependent mortality function using 28 published cold treatment studies of pest fly species to support more flexible and proportionate use of cold treatment. The daily mortality rate was unaffected by the duration of cold exposure (0–20 days). The mortality rate varied primarily by pest species (10 species) and developmental stage (eggs and larval stages), and to a lesser extent by temperature (0–7 °C) and host (13 fruit types). Our model mostly predicted fewer days to meet probit 9.0 mortality compared to empirical results from large-scale studies, suggesting these studies can be overly conservative. By leveraging previous empirical studies, our model enables estimation of temperature-dependent daily mortality for unstudied pest developmental stage host–temperature combinations, which can then be empirically validated through targeted studies. It is hoped these results will shift cold treatment usage from highly regulated, fixed temperature treatments with a target mortality rate requirement to a more flexible approach that accounts for existing commercial supply chain practices and infestation likelihood in produce.