Pest Management Science

BACKGROUNDThe soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a pest of soybean in North America that can cause significant yield loss when outbreaks are not managed. Current management tactics primarily rely on inexpensive pyrethroids, but the sustainability of this option is threatened by insecticide-resistance in A. glycines populations across the Upper-Midwest United States. Field-evolved resistance is associated with mutations in the voltage-gated sodium channel subunit h1 (vgsc-h1) gene. RESULTSFour double-stranded RNA (dsRNA) molecules, each matching the sequence of a vgsc-h1 transcript variant ("Specific dsRNAs"), were topically applied to aphids with a genotype carrying the corresponding allele. The mortality of pyrethroid resistant aphids exposed to a Specific dsRNA increased in a dose-dependent manner when applied alone or with a constant concentration of lambda-cyhalothrin, plateauing at 1000 ng ul-1. Synergism was detected between two of four combinations of the Specific dsRNAs and lambda-cyhalothrin. These results were mirrored by the topical application of a single dsRNA with the consensus sequence of all vgsc-h1 variants ("Combined dsRNA"). Mortality was consistently higher in aphids treated with either Specific dsRNA or the Combined dsRNA, alone or with lambda-cyhalothrin, compared to insecticide alone. The number of nymphs produced per female treated with the Specific or Combined dsRNA alone decreased significantly compared to untreated controls. CONCLUSIONThis study demonstrates that the topical application of dsRNAs targeting vgsc-h1 increases the susceptibility and reduces the reproductive capacity of pyrethroid resistant soybean aphids, potentially providing a novel tool for the management of insecticide-resistant aphid populations.

Pesticides remain indispensable for global food security, yet their use must be reconciled with the preservation of biodiversity. Despite advances in developing safer pesticides, their sublethal effects and synergistic potential with co-formulants in tank-mixtures, including inert spray adjuvants, often remain poorly understood in beneficial insects like bees. In this study, we assessed the effects of acute oral exposure to field-realistic doses of SilwetTM L-77 (an organosilicone adjuvant; 0.1-2.5%), acetamiprid (a cyano-substituted neonicotinoid; 6-150 ng/bee), and sulfoxaflor (a sulfoximine; 3-27 ng/bee) on gustatory responsiveness, associative olfactory learning, and short-term memory retention in honeybees (Apis mellifera L.). While we found no significant evidence of interaction effects at the exposure concentrations tested, the highest doses of SilwetTM L-77 and sulfoxaflor alone significantly reduced gustatory responsiveness. Furthermore, all three agrochemicals alone weakly affected associative learning without impacting memory retention. Although adjuvant-insecticide mixtures did not synergistically impair bee cognition, these adjuvants can impact sensory perception. Moving beyond mortality-based assessments and including sensory-cognitive thresholds is essential for a more holistic understanding of pollinator health.

Drosophila suzukii (Matsumura, 1931, Diptera: Drosophilidae) is a globally invasive pest of soft-skinned fruits that is currently controlled largely through the use of broad-spectrum insecticides. Increasing resistance to pesticides and regulatory pressures have motivated the development of genetic control strategies. We previously developed a CRISPR/Cas9-based homing gene drive targeting the coding sequence of the female-specific exon of the sex-determination gene doublesex, achieving highly efficient inheritance (94-99%) in both male and female germlines. A major limitation of homing gene drives is the formation of resistant alleles that evade cleavage yet retain gene function. Multiplexing guide RNAs (gRNAs) could reduce the formation of such functional resistance alleles. Here, we generated and tested homing constructs expressing one, two, or three gRNAs targeting different regions of the female-specific exon of doublesex, including a splice-junction target site. A single gRNA targeting the splice junction supported high inheritance in males but showed reduced efficiency in females. Combining this gRNA with a coding sequence-targeting guide further reduced drive efficiency, particularly in the female germline. Constructs expressing two gRNAs performed similarly whether guides were linked by transfer RNA (tRNA) sequences or expressed from independent promoters. Constructs expressing three gRNAs using tRNA processing showed consistently low drive inheritance in both sexes, likely a consequence of reduced cleavage efficiency due to inefficient gRNA production. Inheritance was significantly higher in male than female germlines for several constructs, indicating that germline context strongly influences drive performance. Our findings highlight that the approach used for multi-gRNA expression, target site choice and sex-specific germline environments can impact gene drive efficiency, and emphasize the need to optimize construct design within the biological context of the target species.

BackgroundAttractive Targeted Sugar Baits (ATSBs) are a promising, environmentally friendly approach for mosquito control, but the direct field application, scalability and long-term effectiveness of ATSBs across diverse mosquito species remain significant challenges. Methodology/Principal FindingsWe assessed the efficacy of a genetically engineered RNA interference (RNAi) yeast strain (Sh.463_56.10R) formulated in three sugar baits, soda (Coca-ColaTM), 10% sucrose, and a commercial mosquito bait (BaitStabTM), on Aedes, Anopheles and Culex mosquitoes. All RNAi yeast bait formulations induced significantly higher mean mortality (87-100%) compared to the control groups (0-9%; P<0.0001), but mosquitoes exhibited a higher feeding preference for RNAi yeast-soda baits, which induced mortality rates of 94-100% (P < 0.0001) recorded across all mosquito species. Additionally, to assess the competitiveness of the RNAi yeast-soda bait to other tropical sugar sources, semi-field choice assays were conducted in Trinidad, West Indies using competing flowering plants and fruits typically found in residential environments. The RNAi yeast-soda ATSB continued to perform well in the presence of competing floral and fruit sugar sources during both Aedes albopictus and Culex quiquefasciatus trials, though the presence of several fruits and flowers did reduce A. aegypti mortality, suggesting that further field testing will be necessary. The residual activity of the Sh.463_56.10R + soda formulation was retained for at least 14 months, with sustained 100% mortality in C. quinquefasciatus and 93-100% mortality in Aedes aegypti, Anopheles gambiae and Anopheles stephensi. The RNAi yeast-soda ATSB also performed well in semi-field studies performed with a prototype soda bottle feeder. Conclusions/SignificanceThis study demonstrates the potential of soda-baited RNAi yeast as a potent, long-lasting, and scalable platform for ATSB-based mosquito control as a component of integrated vector management programs. Author SummaryMosquito-borne diseases continue to affect millions of people worldwide, and current mosquito control methods face challenges such as low public uptake, insecticide resistance and environmental concerns. Here we evaluated a new and environmentally friendly approach to mosquito control using ATSBs. We tested genetically engineered species-specific yeast producing RNAi molecules capable of killing mosquitoes that feed on it. We mixed the yeast with three different sugar baits, including soda (Coca-ColaTM), 10% sucrose, and the commercial mosquito bait BaitStabTM formulation, and evaluated how well they worked against different mosquitoes. The results showed that the RNAi yeast mixed with soda was the most effective, killing up to 100% of mosquitoes in laboratory and outdoor tests. The bait remained effective in the presence of many competing natural tropical fruit and floral sugar sources. Remarkably, the bait, which can be delivered in a soda bottle feeder, stayed active for at least 14 months under simulated field conditions. These findings suggest that soda-based RNAi yeast baits could provide a practical, long-lasting and scalable tool for mosquito control and may help strengthen future strategies to reduce mosquito-borne diseases.

Ghana is the largest exporter of yams in West Africa. However, yam production, particularly seed yam production, is constrained by storage rot during the off-season. Farmers seldom use synthetic pesticides to control seed yam rot. However, these are costly and pose adverse health risks to farmers. Biological antagonists offer a sustainable, relatively cost-effective, and safe alternative to synthetic pesticides. Therefore, this study aimed to test the efficacy of Bacillus subtilis as an alternative to synthetic pesticides. Bacillus subtilis supplied through the biofungicide Serenade ASO (Bayer) was assayed against three storage-rot pathogens: Lasiodiplodia theobromae, Aspergillus niger, and Rhizopus sp. These pathogens were previously isolated from the tissues of rotten seed yams. The efficacy of the bacterium was tested at concentrations of 17 %, 33 %, and 50 % in both in vitro and in vivo bioassays. B. subtilis (50 %) completely inhibited the growth (100 %) of L. theobromae in the in vitro studies. In contrast, there was little to no growth inhibition of the other two test fungi. In the in vivo assay, B. subtilis (50%) significantly (P < 0.01) inhibited L. theobromae, resulting in minimal rot lesions. However, B. subtilis (50 %) was ineffective against the other two test pathogens, resulting in large rot lesions on the seed yams. This suggests that B. subtilis could be an ideal alternative to synthetic pesticides for controlling L. theobromae on seed yams.

O_LIOver the past decade, leafhoppers (Hemiptera: Cicadellidae) have gained increasing attention as pests and vectors of phytoplasma diseases in Quebec. C_LIO_LIDrawing on historical and modern reports spanning 1868 to 2025, we investigate whether leafhopper pest status has been changing in the province, focusing on two leafhopper groups: those that overwinter in Quebec (local species) and those that do not (migratory species). C_LIO_LILocal species have been reported as pests since at least 1886 and have been considered of secondary significance. Migratory species, first mentioned in 1908, have been listed more frequently as economically important. C_LIO_LIEmpoasca fabae and Macrosteles quadrilineatus were associated with 10 crops, accounting for 11-88% of adult specimens in reported crop assemblages. On the other hand, local species, such as Erythroneura ssp. and Zonocyba (= Typhlocyba) pomaria, were reported mainly on grapevines and apples, respectively. C_LIO_LIWe found that the first field reports of leafhoppers from 1997 to 2025 are advancing in crops where migratory species are most frequently reported (e.g., potato and strawberry), whereas in crops where local species appear to predominate, no significant association was found (e.g., apple and grapevine). C_LIO_LIOur findings indicate that recent changes in leafhopper pest status in Quebec are likely due to migratory species, a group that has historically been a significant component of the leafhopper assemblage on agricultural crops. In Quebec agriculture, what was once loin des yeux, loin du cur (out of sight, out of mind) appears to be shifting toward pres des yeux, pres du cur (now visible and therefore important). C_LI GRAPHICAL ABSTRACT AND HIGHLIGHTS O_FIG O_LINKSMALLFIG WIDTH=185 HEIGHT=200 SRC="FIGDIR/small/727661v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1c58d5forg.highwire.dtl.DTLVardef@c45e02org.highwire.dtl.DTLVardef@1f801ceorg.highwire.dtl.DTLVardef@13eb7e3_HPS_FORMAT_FIGEXP M_FIG C_FIG O_LIThe pest status of leafhoppers has changed in Quebec over recent decades, but whether local or migratory species are driving this shift remains unknown. C_LIO_LILocal species have been recognized as pests since at least 1886, and migratory species since 1908. However, migratory species were more frequently reported in historical documents. C_LIO_LIMigratory species (Empoasca fabae and Macrosteles quadrilineatus) appear to be driving the recent status change, as evidenced by earlier first reports and presence across multiple crops. C_LI

Electroantennography (EAG) is a valuable approach for monitoring the sensory responses of insects to insecticidal and repellent molecules and an effective tool for early screening of compounds aimed at controlling and protecting against medically important insect vectors. However, its predictive potential for repellent efficacy in triatomine vectors remains poorly explored. The objective of this study was to evaluate the EAG responses to different xenobiotics as a preliminary selection strategy for compounds with potential repellent action against triatomines. For this purpose, the antennae of adult triatomines subjected to prolonged fasting ([&ge;]30 days) were exposed to repellent molecules. In parallel, repellency bioassays were conducted using a live bait (Gallus gallus) and a newly designed laboratory device to validate the electroantennographic results. EAG recordings showed a significant reduction in olfactory capacity of> 60% in response to the chemical compounds IR3535 and carvone, consistent with the protection times observed in the repellency tests (135.6 {+/-} 43.29 min and 108 {+/-} 26.33 min, respectively). In conclusion, the compounds with the highest repellent activity were clearly discriminated by the insects olfactory system, a finding corroborated by the decrease in electrical signals recorded in the EAG bioassays.

Plant-parasitic nematodes (PPNs) are among the most destructive agricultural pests worldwide, causing significant economic losses across diverse cropping systems. Soil fumigation, the most common management strategy, is costly, detrimental to soil health, and increasingly restricted due to environmental and regulatory concerns. As a result, there is a critical need for alternative, sustainable approaches for PPN control. Solanum sisymbriifolium is resistant to several Meloidogyne species and represents a promising source of natural nematicidal compounds. In this study, we evaluated the effects of S. sisymbriifolium extracts on Meloidogyne chitwoodi and M. hapla, two economically important nematodes. Compounds were extracted using solvents of increasing polarity and then reconstituted in water. The water-solubilized extracts were then used in bioassays to assess their effects on nematode egg hatching, egg viability, and second-stage juvenile (J2) survival. Egg hatching and J2 viability of both Meloidogyne species were consistently affected by compounds in the 1-butanol fraction. Further characterization of these compounds may enable the development of novel, environmentally sustainable alternatives to conventional nematode management strategies.

IntroductionProgress against malaria has stalled since 2015, with insecticide resistance a key driver. Spatial emanators release volatile insecticides into the air, exposing mosquitoes through a route distinct from the tarsal contact used by treated nets, indoor residual spraying, and standard bioassays. Transfluthrin is currently monitored using the WHO bottle bioassay, which combines contact and vapour exposure and cannot isolate airborne effects. A scalable, vapour-only method is needed to characterise susceptibility to volatile pyrethroids. MethodsWe adapted the WHO tube bioassay to deliver non-contact transfluthrin vapour exposure without contacting treated papers. Non-blood-fed female Anopheles were exposed to acetone control or transfluthrin papers at 0.005, 0.1 and 2 mg/paper. Knockdown was recorded over 60 minutes and mortality at 24 hours. Testing spanned three laboratories (LSTM, AIRID and KEMRI) using susceptible reference and resistant lab colonies. Dose response models estimated EC{square}{square} for knockdown (EC{square}{square}KD) and mortality (EC{square}{square}Mort), with resistance ratios (RR) against the local susceptible reference. ResultsThe assay generated clear concentration- and time-dependent responses. At LSTM, Kisumu gave an EC{square}{square}KD of 0.052 and EC{square}{square}Mort of 0.054 mg/paper; Siaya was comparable (RR{square}{square}KD 1.17, RR{square}{square}Mort 0.89), whereas Tiassale 13 and KDR showed reduced susceptibility (RR{square}{square}KD 2.42 and 2.85; RR{square}{square}Mort 5.56 and 6.65). At AIRID, the resistant Cove strain did not reach 50% knockdown or mortality. At KEMRI, Siaya showed reduced susceptibility (RR{square}{square}KD 3.36/RR{square}{square}Mort 5.65). Kisumu at AIRID and KEMRI was comparable to LSTM (EC{square}{square}KD 0.007/EC{square}{square}Mort 0.030; EC{square}{square}KD 0.044/EC{square}{square}Mort 0.023). Despite inter-laboratory variation, susceptible strains remained distinguishable from resistant ones. Lower RRs than for contact pyrethroids suggest contact-based phenotypes may not predict vapour susceptibility. ConclusionThe assay provides a practical benchtop method using standard WHO hardware, distinguishing susceptible from resistant strains across three laboratories. Twenty-four-hour mortality is the recommended endpoint, 60-minute knockdown secondary. Not yet validated, it provides a foundation for further validation and adaptation to other actives.

Most organisms have evolved mechanisms to reduce the negative effects of toxins in their diet. Some animals that are toxin specialists, such as dendrobatid poison frogs, have amino acid substitutions in proteins targeted by the toxins that prevent or limit the toxins ability to bind and exert its bioactive effects. The Phantasmal poison frog, Epipedobates tricolor, has amino acid substitutions in its neuronal nicotinic acetylcholine receptors that were previously shown to provide resistance to the highly potent neurotoxin epibatidine in vitro. However, it is unclear whether E. tricolor resists the physiological effects of epibatidine in vivo. To investigate this, we examined the effects of epibatidine exposure on the locomotion and behavior of E. tricolor. We performed whole-animal performance assays and behavioral evaluations at multiple time points following the administration of high yet biologically relevant levels of epibatidine. These assays were followed by alkaloid quantification to track chemical concentrations in the skin. Epipedobates tricolor exhibited similar locomotor performance and behavior at both epibatidine doses compared to controls and regardless of the quantity of alkaloid accumulated into the skin. However, we observed an impact of low-percentage ethanol solutions on behavior when compared to water controls, as well as general impacts of handling stress (regardless of the administered solution type), which should be considered in future experimental designs. Overall, we demonstrate that E. tricolor likely avoids a physiological fitness trade-off between toxin ingestion and the defensive benefits of epibatidine sequestration. Our study suggests that the ability to ingest toxins involves multi-faceted resistance mechanisms. Highlights- Whole-animal performance assay shows no impact of epibatidine on frog behavior - Epipedobates tricolor is 20-5000 times more resistant to epibatidine than mice - Assays demonstrate that frogs are sensitive to 6% ethanol and handling stress

1In 2024-2025 a multi-centre study involving seven international laboratories was conducted with the support of the World Health Organization (WHO). The aim of the study was to establish and validate discriminating concentrations (DCs) in WHO bottle bioassays for monitoring susceptibility to broflanilide and isocycloseram in Anopheles gambiae s.s., An. funestus, An. stephensi and Aedes aegypti. The following values are recommended for adoption as DCs for broflanilide: 10 {micro}g/bottle for An. gambiae and Ae. aegypti, 15 {micro}g/bottle for An. funestus, and 25 {micro}g/bottle for An. stephensi. The recommended DCs for isocycloseram are 15 {micro}g/bottle for Ae. aegypti, 30 {micro}g/bottle for An. gambiae, 50 {micro}g/bottle for An. stephensi, and 60 {micro}g/bottle for An. funestus. Based on the experiences of conducting this study, which represents the application of a generic protocol for establishing discriminating concentrations produced by the WHO, technical recommendations are made on the generation and analysis of DC data for insecticides in future.

The blood-sucking ectoparasite Rhipicephalus B. microplus represents one of the greatest economic threats to livestock worldwide. The discovery of novel acaricidal molecules based on environmentally sustainable technologies is therefore required, particularly those suitable for use in dairy and meat-producing livestock without generating contaminant residues. This study aimed to identify and validate plant-derived metabolites with dual activity on acetylcholinesterase and mitochondrial targets as sustainable acaricidal agents against R. microplus, integrating computational screening, biochemical assays and field evaluation. Following in silico screening of 1.300 plant metabolites targeting acetylcholinesterase and mitochondrial function, fourteen compounds were selected for in vitro and in vivo mortality assays using immersion and larval vessel methods. Carvacrol was identified as the most promising metabolite and showed an inhibitory mechanism of action on acetylcholinesterase and mitochondrial complexes I, III, and IV. Its acaricidal efficacy was subsequently confirmed under field conditions using ethanolic and oily formulations (spray and pour-on) applied to cattle (Bos taurus). The spray formulation significantly reduced tick infestation, decreasing tick counts by 20% every 10 days (p < 0.001), whereas the pour-on formulation showed no significant reduction (p = 0.093). These results demonstrate that an integrated discovery pipeline from computational screening to field validation provides a robust strategy for identifying plant-derived acaricidal agents targeting key physiological pathways in R. microplus. HighlightsO_LIStructured and sequential workflow (pipeline) from in silico to Bos taurus C_LIO_LIIdentification and validation of phytometabolites against R. microplus C_LIO_LICarvacrol multitarget activity on acetylcholinesterase and bioenergetic in ticks C_LIO_LIThe spray formulation reduces tick infestation by 20% every 10 days C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/727743v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@11c9931org.highwire.dtl.DTLVardef@8d6088org.highwire.dtl.DTLVardef@1bcc09aorg.highwire.dtl.DTLVardef@108d1d1_HPS_FORMAT_FIGEXP M_FIG C_FIG Created in BioRender. Avendano, G. (2026) https://BioRender.com/7pm1ffj

Bacillus thuringiensis INTA Mo4-4 was characterized phenotypically, genomically, and for insecticidal activity against Alphitobius diaperinus. Microscopy revealed rare flat rectangular parasporal crystals, and SDS-PAGE identified a ca. 67 kDa protein, similar to B. thuringiensis serovar morrisoni strain tenebrionis DSM-2803, which was proteolytically processed to a ca. 55 kDa fragment. Genomic analysis showed a 5.99 Mb genome with 99.43% completeness, clustering phylogenetically with B. cereus and B. thuringiensis. High genomic similarity was observed with B. thuringiensis svar. morrisoni BGSC 4AA1, confirmed by MLST analysis assigning it to ST-23. The genome encodes an interesting arsenal of pesticidal proteins showing significant similarity to Cry3Aa, Mpp23Aa, Xpp37Aa, Mpp5Ab, Vpb1Ad, Vpb1Ae, Vpa2Ab, Vpa2Ba, Vpa2Bb and Spp1Aa, with demonstrated toxicity against coleopteran pests. Biosynthetic gene clusters for toyoncin, fengycin, and bacillibactin were identified. Dose-response bioassays showed that INTA Mo4-4 was nearly four times more toxic to A. diaperinus larvae (LC50 136.9 {micro}g/ml) than DSM-2803 (LC50 540.5 {micro}g/ml), with the difference being statistically significant. No teratological effects were observed on Musca domestica. These findings suggest that INTA Mo4-4 is a promising candidate for the biological control of A. diaperinus.

Insecticide treated nets (ITNs) remain one the frontline tool in malaria control in Africa. The synergist piperonyl butoxide (PBO) has been incorporated into ITNs to combat pyrethroid resistance and these pyrethroid-PBO ITNs are now in widespread use across Africa. PBO is known to inhibit the degradation of pyrethroids and other insecticide classes, but little is known about other biological or behavioural effects of PBO exposure. This work assessed the impact of PBO on Anopheles gambiae s.l. male longevity as well as female host-seeking and blood feeding behaviours using laboratory assays. PBO had an immediate impact on blood feeding of female An. gambiae s.l. whereas the effect was not observed 24h post-exposure. Kaplan-Meier survival curves showed a significant difference in mosquito longevity post-exposure to PBO with male mosquitoes living nearly three times as long if exposed to control papers compared to PBO. In olfactometer assays, after exposure to control papers, control mosquitoes were significantly more attracted to host-odours, however, this attraction preference was reversed following PBO exposure. This study shows that in experimental assays, PBO has other effects on mosquito physiology and this is likely to contribute to the impact of pyrethroid - PBO ITNs in vector control programmes.

Herbicide resistance threatens effective weed control in modern agriculture, particularly in grass weeds such as Alopecurus myosuroides and Lolium multiflorum. Cinmethylin is a pre-emergence herbicide with a novel mode of action that inhibits plastidial fatty acid thioesterases (FATs), enzymes essential for fatty acid biosynthesis. Although no cases of field resistance to cinmethylin have been reported, its resistance risk has not been fully assessed. In this study, we biochemically characterized defined amino acid substitutions in FAT A and FAT B to evaluate their effects on cinmethylin inhibition profile. Some substitutions in FAT A reduced inhibition in vitro, with mutations at residue R171 causing the largest shifts in sensitivity. However, these highly resistant variants required multiple specific nucleotide polymorphisms and are therefore predicted to be unlikely to arise in weed populations. In FAT B, sensitivity shifts were generally moderate. Importantly, most substitutions that reduced cinmethylin sensitivity also impaired enzymatic activity, suggesting limited viability in planta. Overall, these results indicate that while theoretical target-site resistance mechanisms exist, the practical risk of rapid resistance evolution to cinmethylin is low, supporting its value for integrated grass weed management

In eastern Canada, the seedcorn maggot complex (SMC) includes three agriculturally important taxa: Delia platura biotypes H and N, and D. florilega. Because their larvae are morphologically indistinguishable, field-collected individuals are often grouped together despite differences in phenology and life history. Using larval collections from broccoli, green onion, and dry onion fields in Southern Quebec (2017-2022), we identified specimens via HRM analysis and characterized taxon-specific phenology and abundance using Bayesian hierarchical generalized additive models. In Allium crops, D. platura biotype N dominated early-season infestations (May), followed by a shift in early June towards increased abundance of biotype H and D. florilega. In broccoli, all SMC members appeared later, with overlapping abundance peaks in June. These results reveal strong crop-dependent phenological differences and underscore the need to treat SMC members as distinct biological entities in pest management. The implications for optimizing an emerging sterile insect technique (SIT) program for D. platura in Quebec are significant: field releases of sterile males should target early-season biotype N in Allium crops, followed by releases of both biotypes later in the season in broccoli to maximize control efficacy.

Plant-gall wasp systems provide unique models for studying multitrophic interactions and unique developmental trajectories, yet standardized laboratory protocols for maintaining wild rose hosts (Rosa spp.) and sustaining gall inducers (Diplolepis spp.) are lacking. We developed and tested a method for growing and maintaining translocated individuals of Rosa canina, R. rubiginosa, R. spinosissima, R. gallica, R. tomentosa, and R. pendulina under laboratory conditions over three consecutive years (2023-2026). The goal was to have a constant supply of plant host material for reliably producing galls of D. rosae and D. mayri for experimental use. The protocol integrates soil and substrate composition, photoperiod and humidity regimes, pruning, dormancy management, and controlled exposure to gall-inducing wasps. More than 75% of rose individuals survived the full 3-year period, with consistent annual gall induction across some of the species. This work represents the first reproducible laboratory method for long-term maintenance of wild rose hosts and controlled gall induction by Diplolepis species, while also providing a transferable framework for maintaining perennial woody hosts and experimentally manipulating specialized plant-insect interactions under laboratory conditions, thereby providing a platform for ecological, physiological, and evolutionary studies on these interactions.

Identifying the sensory cues that enable insects to find host plants, and understanding the neurobiology underlying their selection, provide solid foundations for developing state-of-the-art pest management strategies. Our work was aimed at identifying the main sensory cues attracting the leaf-cutting ant Acromyrmex ambiguus to alternative host plants in commercial willow plantations in the Lower Delta of the Parana River (Argentina), with a focus on native plant species. Eight plant species were selected and evaluated as potential hosts under field and laboratory conditions, allowing the establishment of a robust hierarchy of preference based on individual and collective behaviour. As a result, Senna corymbosa emerged as the most preferred species, whereas Blepharocalyx salicifolius was the least preferred. Video analyses of ant foraging in controlled indoor nests revealed a sequential decision-making process underlying plant preference and consumption. This included an initial approach driven by olfactory cues, followed by a second step involving contact-dependent cues that elicited leaf-cutting and carrying the leaf fragments to the nest. Volatile compounds and leaf cuticular components potentially involved in plant preference were identified. In addition, physicochemical analysis of both plant species - including total sugars, organic matter, polyphenols, leaf hardness, total proteins and lignin-revealed differences, particularly in polyphenol content, which may contribute to preference patterns. These findings provide insights into the sensory ecology of host preference and inform management strategies based on the reintroduction of native plants as alternative resources in willow plantations, potentially reducing pesticide use and promoting environmental sustainability. Summary statementThis work shows how leaf-cutting-ants rely on olfactory and contact cues, sequentially, for foraging decision-making of plant species. Thus, revealing how sensory cues shape their foraging decisions.

Horseweed (Erigeron canadensis) is a widely distributed annual weed that can cause significant yield losses if not properly controlled. Its phenotypic plasticity allows it to rapidly acclimate to new environmental conditions, such as drought and herbicides, such as glyphosate, with the potential for cross stress acclimatization. The objectives of this research were to uncover the physiological and genetic effects at the intersection of drought stress and glyphosate resistance. To this end, we performed greenhouse dose response experiments, RNAseq, 14C glyphosate absorption and translocation, and cuticular lipid profiling via GC/MS. Greenhouse dose-response experiments revealed that, after drought stress, there was a 2.5-3.7 fold reduction in glyphosate sensitivity via a significant reduction in glyphosate absorption, regardless if the starting population was resistant or susceptible to the field use rate already. Cuticular waxes were collected from each population with and without drought stress and were analyzed via GC/MS. When comparing total wax loads of plants grown under WW and DS conditions, we found that drought stress significantly increased total wax loads for all three populations. Additionally drought stress substantial increases the proportion of triterpenoids in the cuticle. By RNAseq, we found serval triterpenoid biosynthesis genes upregulated after drought, which likely drive the changes in cuticle composition and ultimately increased glyphosate resistance following drought. Ultimately, understanding how drought impacts glyphosate resistance is critical for maintaining optimal weed control in the changing climate. HighlightDrought stress induces changes to cuticle composition and gene expression that reduce glyphosate absorption, thereby increasing horseweeds ability to survive glyphosate application.

While a growing number of studies have linked environmental exposures and Parkinsons disease (PD)1-3, the impact of many pesticides remains understudied4,5; for example, neonicotinoids are the most used insecticides in the world, but research into their contribution to PD is limited to a handful of studies6-8. Newer pesticides, such as the butenolide flupyradifurone (FPF), specifically developed to overcome increased pest resistance9 and spurred on by tighter restrictions on neonicotinoids such as imidacloprid (IMI)10, are even less studied. New approach methodologies (NAMs) that allow for rapid evaluation of pesticide exposures are needed to evaluate potential links between the growing number of pesticides and PD11. To this end, we exposed the model nematode Caenorhabditis elegans12 to IMI and FPF. Due to its high degree of tractability, and conservation of many genetic, neuronal, and toxic mode of action processes, C. elegans has been invaluable in both elucidating mechanisms and novel therapeutic targets for PD that can be validated in other models13, and as a complementary tool for early toxicity screening14. Along this line, we found that exposure to IMI, and to a greater extent FPF, in young adult animals causes significant dendritic blebbing, an early sign of neurodegeneration, exclusively in dopaminergic neurons. Blebbing was accompanied by impairment of dopamine-mediated behaviors, changes in neuronal mitochondrial morphology, and elevation of pathways related to reactive oxygen species (ROS). We were able to reduce the blebbing caused by IMI and FPF two ways: 1) pharmacologically via administration of the antioxidant N-acetyl cysteine (NAC); 2) genetically via knockout of a MAP kinase (MAPK) stress response pathway. This suggests that oxidative stress is a key mediator of this insecticide-induced dopaminergic neurodegeneration.