Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) and Spodoptera litura (Fabricius) are the main pests on corn (Poaceae: Gramineae). The performance of the larval wasp, Microplitis pallidipes Szépligeti (Hymenoptera: Braconidae), was reported on S. frugiperda and S. litura. In this study, we evaluated host selectivity, constructed an age–stage, 2-sex life table, and assessed the pest control potential of M. pallidipes against these 2 pests under laboratory conditions. In a 2-choice host preference experiment, M. pallidipes exhibited a stronger preference for S. frugiperda over S. litura and a distinct preference for second instars. We also investigated the parasitism of females that were either unfed or fed with 10% honey–water solution under different host densities and found that the highest parasitism rate was observed when M. pallidipes were fed with honey–water solution on the first day after mating and a presented female wasp:host ratio of 1:90. In a nonselective assay, M. pallidipes successfully completed a full generation on both hosts. However, the parasitoids exhibited higher fitness and population growth potential when reared on S. frugiperda, with a net reproductive rate (R₀) of 24.24, an intrinsic rate of increase (r) of 0.20 per day, a finite rate of increase (λ) of 1.23 per day, and a mean generation time (T) of 15.69 days. This study elucidates the performance of M. pallidipes on 2 Spodoptera host species and offers insights into its biological control potential on lepidopteran pests.

Graphical Abstract

Nutrition has been identified as a key driver of colony health and productivity. Yet, in honey bees, relatively little is known about how the vast variety of natural pollen sources impact larval development. The impact of the nutritional quality of 4 naturally occurring pollen sources, of importance to the Western Australian beekeeping industry, was tested on honey bee (Apis mellifera L.) development. Bee packages consisting of 800 g of bees and a mated sister queen were assigned to 40 nucleus hives and randomly allocated to one of the 4 feed treatments (10 colonies each) of marri (Corymbia calophylla Lindl.), jarrah (Eucalyptus marginata Sm.), clover (Trifolium repens L.), and canola (Brassica napus L.) pollen. Emerging bees were collected once the first bees started hatching on the assigned feed sources. Newly emerging bees were weighed individually, and body composition was measured in batches according to the feed treatment groups. Food consumption was recorded for the duration of the experiment. Nurse bees successfully raised young adult workers from the larval stage until emergence when fed with one of 4 pollen patties with different nutritional qualities.There was no difference in the body composition or weight of emerging bees fed on the different pollen types. However, the body weight of bees increased over time, most likely related to colony size and structure. With the type of pollen patties having little impact on larval development, the availability of pollen may be more important than its composition, providing bees have access to all essential nutrients.

Given the rapid spread and potential harm caused by the small hive beetle, Aethina tumida (Coleoptera: Nitidulidae) in China, it has become imperative to comprehend the developmental biology of this invasive species. Currently, there is limited knowledge regarding the impact of A. tumida female oviposition site preference on larval growth and development. To examine this, we investigated the ovipositional preference of adult female A. tumida on bee pupae, beebread, banana, and honey through a free choice test. Furthermore, we assessed the impact of these food resources on offspring performance, which included larval development time, survival, wandering larvae weight, emerged adult body mass, reproduction, and juvenile hormone titer. Our results showed that A. tumida females exhibited a strong preference for ovipositing on bee pupae compared to other diets, while showing reluctance toward honey. Moreover, A. tumida larvae that were fed on bee pupae displayed accelerated growth compared to those fed on other diets. Furthermore, A. tumida fed on bee pupae exhibited higher weights for wandering larvae, and emerged adult, increased pupation rates, enhanced fecundity and fertility, as well as a larger number of unilateral ovarioles during the larval stage when compared to those fed on other diets. Overall, the results indicate that the oviposition preferences of A. tumida females are adaptive, as their choices can enhance the fitness of their offspring.This finding aligns broadly with the hypothesis of oviposition preference and larval performance. This study can provide a foundation for the development of attractants aimed at promoting the oviposition of the A. tumida adults.

Wild bumble bees (Hymenoptera: Apidae) play a vital role in agro-ecosystems as important pollinators. However, they are threatened by virus pathogens that are widespread in honey bees. Previous studies have reported that viruses were able to be transmitted across bee genera and caused potential danger to wild bumble bees. China is a global biodiversity hotspot for bumble bees. However, the impact of viruses on the wild bumble bee communities remains elusive. Black queen cell virus (BQCV) is one of the most common honey bee viruses. Here, a total of 72 wild bumble bee samples from 17 geographic regions of China were tested for BQCV. Thirteen positive samples were identified and sequence comparison of partial capsid genes demonstrated a genetic identity of 99.69% to 100%. A phylogenetic tree analysis also showed a close relationship between 13 BQCV isolates and others from a variety of recorded hosts in China. Meanwhile, a distinct evolutionary branch of China isolates was formed when clustering isolates from worldwide bumble bee species. A correlation between BQCV and their geographic locations were observed (P < 0.05).This study not only provides the first evidence of widespread BQCV in wild bumble bee communities in China but also detects a distinct set of genetically identical or closely related BQCV variants that circulate and evolutionarily differ from other countries.

Hot water mound drench treatment has broad application prospects in the control of the red imported fire ant (RIFA), Solenopsis invicta Buren (Hymenoptera: Formicidae). However, much work still needs to be carried out to provide a theoretical basis and technical support for the use of this method against RIFAs under field conditions. In this study, we monitored the temperature changes at different depths within RIFA nests during laboratory-simulated hot water mound drench experiments and evaluated the lethal effect of hot water treatment on RIFAs. Furthermore, the targeted removal effect of hot water mound drench treatment on RIFA nests under field conditions was evaluated. Results indicated that the temperature at depths of 5, 15, and 25 cm inside the simulated ant nests was higher than 51.1 °C within 30 min after treatment, resulting in a 100% mortality rate for RIFAs at all tested depths. Under field conditions, when nests were disturbed, the percentage of RIFAs crawling out of their nests gradually increased with time after disturbance, reached its maximum value at 25 or 30 s after the disturbance, and then gradually decreased. Single hot water mound drench treatment (each ant nest was treated with 17.8–21.6 liter of hot water at a temperature of 97–100 °C) can significantly reduce the RIFA population in ant nests and lead to a 72.7% reduction in the number of surviving ant nests. However, the safety, operability, and timelines of hot water mound drench treatment for RIFA field control still need further investigation.

Weed management is challenging for vegetable crops that are highly sensitive to weed competition, such as onions. Thrips (Thysanoptera: Thripidae) are major insect pests of onions, causing damage through feeding, and vectoring bacterial pathogens causing bulb rot. Both thrips and their associated pathogens are known to survive on many weed species in onion growing regions. Combining weeding with biopesticides may synergistically manage thrips and reduce disease prevalence. However, disturbances from weeding may negatively impact natural enemies. We estimated the effects of organic weed management and biopesticides on weed density, thrips and natural enemy activity, disease severity, and yield. The experiment was a randomized complete block design, with 4 replications of each weeding (control, tine-weeded twice, tine-weeded 4 times, and hand-weeded) and biopesticide (control, OxiDate 2.0, Serenade) combination. Arthropods were monitored using yellow sticky cards, and weed counts, marketable yield, and bulb rot prevalence were estimated. Hand-weeding resulted in the lowest weed density and thrips abundance. Additionally, hand-weeding produced a 9× higher yield compared to all other treatments. Significant interactions were observed between tine-weeding and biopesticide treatments on the prevalence of bulb rot. Natural enemy abundance was slightly negatively impacted by weeding, dependent on the year. DNA metabarcoding results showed high parasitoid diversity in this onion system and high numbers of reads for multiple genera containing important known biological control agents. Our study suggests hand-weeding is necessary in the southeast for maximum onion yield. Future research should focus on exploring the impact of management on natural enemy communities in onion systems on a large scale.

Graphical Abstract

Wolbachia pipientis is a maternally inherited intracellular bacterium that infects a wide range of arthropods. Wolbachia can have a significant impact on host biology and development, often due to its effects on reproduction. We investigated Wolbachia-mediated effects in the Asian citrus psyllid, Diaphorina citri Kuwayama, which transmits Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus greening disease. Diaphorina citri are naturally infected with Wolbachia; therefore, investigating Wolbachia-mediated effects on D. citri fitness and CLas transmission required artificial reduction of this endosymbiont with the application of doxycycline. Doxycycline treatment of psyllids reduced Wolbachia infection by approximately 60% in both male and female D. citri. Psyllids treated with doxycycline exhibited higher CLas acquisition in both adults and nymphs as compared with negative controls. In addition, doxycycline-treated psyllids exhibited decreased fitness as measured by reduced egg and nymph production as well as adult emergence as compared with control lines without the doxycycline treatment. Our results indicate that Wolbachia benefits D. citri by improving fitness and potentially competes with CLas by interfering with phytopathogen acquisition. Targeted manipulation of endosymbionts in this phytopathogen vector may yield disease management tools.

Graphical Abstract

This study determined a cost-effective larval diet for rearing Calliphora dubia Macquart for use as a potential managed pollinator in Australia. This fly has potential as a pollination species to support honey bees (Apis mellifera). Larvae of C. dubia were reared mostly in meat meals with varying amounts of either whole egg powder, whole eggs (+ shell), bran flakes, skimmed milk powder, brewer's yeast, or poultry oil.This was done from an economic and production perspective to support commercial rearing. Several laboratory-based studies determined the growth and output from various ingredient combinations. Larvae fed 90% meat meal and 10% whole egg powder developed rapidly through to pupation with a high pupation rate, adult size, and percent adult emergence. Given the high cost and difficulty in sourcing whole egg powder, media comprising mostly meat meals with the addition of bran flakes and whole eggs also supported rapid larval development, pupation rate, and adult emergence.The ideal amount of media/larvae was 0.5 g/larvae to support high pupation rates and adult emergence. Adult eclosion occurred over 4–5 days, even when larvae were laid and fed within 1 h on ample media. Commercial mass rearing would then require daily cohorts of larvae to ensure peak adult fly emergence over 1–2 days for release into a crop. Mass-rearing C. dubia should use meat meal as the base ingredient with bran flakes and whole eggs added and fed at 0.5 g of media/larvae. Based on the current media ingredient costs, rearing 1-m adult C. dubia would cost just over $500 (US$342).

In this study, we compared the growth, development, and fecundity of Arma chinensis (Fallou) reared on pupae of the geometrid Ectropis grisescensWarren fed on tea shoots during different seasons of the year. The raw data on life history were analyzed using the age–stage, 2-sex life table. When reared on spring or winter geometrid pupae, the duration of the immature stage of A. chinensis was significantly longer than in those produced during the summer or autumn. The survival rate of immature A. chinensis reared on autumn geometrid pupae was significantly lower compared to other treatments. Reproductive diapause was observed in adult A. chinensis reared on winter geometrid pupae. The adult preoviposition period (APOP), total preoviposition period (TPOP), and total longevity were significantly longer in A. chinensis reared on winter pupae than in the other treatments. The fecundity of A. chinensis reared on spring geometrid pupae was significantly lower than in the other treatments. The higher intrinsic rate of increase of the A. chinensis reared on summer pupae (r = 0.0966 day^-1) and autumn pupae (r = 0.0983 day^-1) resulted in higher fecundity, shorter immature duration, and shorterTPOP compared to the winter and spring populations. These findings can be utilized to enhance and sustain biological control of E. grisescens in tea plantations.

Graphical Abstract

Microsporidia Nosema bombycis (Nb) is a cellular parasite responsible for pébrine disease in silkworms, significantly impacting the sericulture industry. Long non-coding RNAs (lncRNAs), which are RNA fragments longer than 200 nucleotides, are pivotal in a range of cellular and physiological functions. However, the potential role of silkworm lncRNAs in response to Nb infection remains unknown. This study conducted transcriptome sequencing on both larvae and Nb-infected midguts of silkworms, identifying 1,440 lncRNAs across all examined midgut samples. Within the Nb-infected group, 42 differentially expressed lncRNAs (DElncRNAs) and 305 differentially expressed mRNAs (DEmRNAs) were detected. Functional annotation and pathway analysis showed that these DEmRNAs are mostly involved in metabolism, apoptosis, autophagy, and other key pathways. The co-expression network of DEmRNAs and DElncRNAs illustrates that 1 gene could be regulated by multiple lncRNAs and 1 lncRNA may target multiple genes, indicating that the regulation of lncRNA is intricate and networked. In addition, the DElncRNA-miRNA-mRNA network showed that some DElncRNAs may be involved in the immune response and metabolism through miRNA. Notably, the study observed an increase in lncRNA MSTRG857.1 following Nb infection, which may promote Nb proliferation. These findings offer insights into the complex interplay between insects and microsporidia.

Polarized growth plays a key role in all domains of their biology, including morphogenesis and pathogenicity of filamentous fungi. However, little information is available about the determinants of polarized growth. The fungal Mep2, Pes1, and Cph1 proteins were identified to be involved in the dimorphic transition between yeast and hyphal forms in Candida albicans. In this study, evidence that the dimorphic fungal entomopathogen Ophiocordyceps sinensis Mep2, Pes1, and Cph1 proteins are involved in polarized growth is presented. OsMep2 was significantly upregulated at aerial hyphae and conidia germination stages. OsCph1 was significantly upregulated at aerial hyphae, conidia initiation, and conidia germination stages, and OsPes1 was significantly upregulated at the conidia germination stage. Deletions of OsMep2, OsCph1, and OsPes1 provoked defects in the polarized growth. The abilities of hyphal formation and the yields of blastospores and conidia for the Δ OsMep2, ΔOsCph1, and Δ OsPes1 mutants were significantly reduced. The conidia yields of the ΔOsMep2, ΔOsCph1, and ΔOsPes1 mutants were decreased by 69.17%, 60.90%, and 75.82%, respectively. Moreover, the pathogenicity of the Δ OsMep2, ΔOsCph1, and Δ OsPes1 mutants against Thitarodes xiaojinensis was significantly reduced. The mummification rate caused by wide type and ΔOsMep2, ΔOsCph1, and ΔOsPes1 mutants were 36.98% ± 8.52%, 0.31% ± 0.63%, 1.15% ± 1.57%, and 19.69% ± 5.6%, respectively. These results indicated that OsMep2, OsCph1, and OsPes1 are involved in the regulation of hyphal formation, sporulation, and pathogenicity of O. sinensis. This study provided a basis for the understanding of the fungal dimorphic development and improving the efficiency of artificial cultivation of O. sinensis.

Sex pheromone analogs have high structural similarity to sex pheromone components. They also play a role in studying many agricultural pests. In our study, (Z, Z, Z)-3,6,9-nonadecadiene (Z3Z6Z9-19:Hy) was successfully synthesized, which is an analogue to 1 of 2 sex pheromone components of Ectropis grisescens Warren (Z, Z, Z)-3,6,9-octadecatriene (Z3Z6Z9-18:Hy), and it showed potential inhibition in experiments. In the electroantennogram test, Z3Z6Z9-19:Hy showed a dose-dependent response, and only measured half the response of Z3Z9-6,7-epo-18:Hy. However, the compound significantly reduced positive response of E. grisescens males by up to 70% in theY-tube olfactometer. Furthermore, in the wind tunnel, it significantly inhibited all types of behavioral responses.The percentage of moths contacting the pheromone odor source was reduced even at the lowest dose tested. In silico study afterward, molecular docking results showed affinity between Z3Z6Z9-19:Hy and sensory neuron membrane protein 1. Our study revealed the potential of Z3Z6Z9-19:Hy as a sex pheromone inhibitor, which would provide new tools for monitoring and mating disruption of E. grisescens.

Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae), a highly destructive pest in Asia, poses a significant threat to maize production by causing substantial yield losses. However, there is a lack of information regarding the impact of temperature variations on its population dynamics and the age-stage and two-sex life table. This study aimed to investigate the impact of 4 temperatures (20 °C, 24 °C, 28 °C, 32 °C) on the development, reproduction, and survival of O. furnacalis under controlled laboratory conditions. Our results revealed that O. furnacalis successfully developed, survived, and laid eggs across the tested temperatures (20–32 °C). The shortest developmental duration for all immature stages was observed at 32 °C. Conversely, increasing temperatures led to decreased longevity. Among the temperatures tested, 28 °C proved to be optimal for O. furnacalis, exhibiting the highest intrinsic rate of increase, finite rate of increase, and net reproductive rate. Our findings indicate that O. furnacalis thrives within a wide temperature range of 20–32 °C, with 28 °C being the most favorable for reproduction. These insights are crucial for predicting population dynamics under diverse climatic conditions and developing effective control strategies against O. furnacalis. This study enhances our understanding of O. furnacalis' life-history traits and provides valuable information for targeted pest management approaches.

In this study, we investigated the biological aspects and predation efficiency of 3 aphidophagous ladybird beetles, Coccinella novemnotata, Hippodamia variegata, and Coccinella septempunctata, on the cotton aphid, Aphis gossypii, reared on cucumber plants (Cucumis sativus L. cultivar barracuda) under laboratory conditions. The developmental periods of C. novemnotata, H. variegata, and C. septempunctata were observed to be 16.00 ± 0.25, 16.00 ± 0.25, and 20.58 ± 0.40 days, respectively. The larvae of these ladybird beetles consumed an average of 218.93 ± 8.86, 254.77 ± 8.86, and 537.36 ± 10.49 aphids, respectively. Fourth-instar larvae were particularly efficient, consuming 53.68%, 52.68%, and 52.64% of total aphids for C. novemnotata, H. variegata, and C. septempunctata, respectively. Adult emergence rates were promising, with 91.67%, 100.00%, and 92.86%, accompanied by sex ratios of 63.64%, 53.84%, and 61.54%, respectively. Notably, a single female of C. novemnotata, H. variegata, and C. septempunctata consumed an average of 2,215.30, 2,232.00, and 3,364.50 aphids, respectively, over its lifespan. Coccinella septempunctata demonstrated the highest predation efficiency among the 3 species, suggesting its potential for biological control of A. gossypii in both open fields and greenhouses, promoting sustainable agricultural practices.

Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is a destructive insect pest of many crops. Rickettsia infection in different cryptic species of B. tabaci has been observed worldwide. Understanding the interactions between these 2 organisms is critical to developing Rickettsia-based strategies to control B. tabaci and thereby reduce the transmission of related vector-borne viruses. In this study, we investigated the effects of Rickettsia infection on the biological characteristics of the Middle East Asia Minor 1 (MEAM1) strain of B. tabaci through biological analysis of infected and uninfected individuals. The results of this study suggest that Rickettsia may confer fitness benefits. These benefits include increased fertility, improved survival rates, accelerated development, and resulted in female bias. We also investigated the transcriptomics impact of Rickettsia infection on B. tabaci by performing a comparative RNA-seq analysis of nymphs and adult females, both with and without the infection. Our analysis revealed 218 significant differentially expressed genes (DEGs) in infected nymphs compared to uninfected ones and 748 significant DEGs in infected female adults compared to their uninfected whiteflies. Pathway analysis further revealed that Rickettsia can affect many important metabolic pathways in whiteflies. The results suggest that Rickettsia plays an essential role in energy metabolism, and nutrient synthesis in the B. tabaci MEAM1, and depends on metabolites obtained from the host to ensure its survival. Overall, our findings suggest that Rickettsia has beneficial effects on B. tabaci and offered insights into the potential molecular mechanisms governing the interactions between Rickettsia and B. tabaci MEAM1.

In an ant colony, a large number of nestmates with a similar gene pool coexist, making them more vulnerable to pathogenic attacks. These pathogens influence the behavior and physiology of the fire ant Solenopsis invicta Buren. Here, we evaluated the impact of entomopathogenic fungi (EPF) Metarhizium anisopliae on the behavior (locomotion and foraging) and physiology (biological molecules, anti-fungal activity, and survival) of S. invicta. Distance traveled and velocity significantly decreased, while turn angle and angular velocity significantly increased in ants exposed to a higher concentration of M. anisopliae compared to ants exposed to control after 36 h, which showed disturbed locomotion. Fungus infection significantly affected the foraging behavior of ants. Fungus-exposed ants spent significantly less time in the food zone (area with food) than in the inner zone (area without food). The activities of 4 enzymes, peroxidase, glutathione-S-transferase, hydrogen peroxide (H₂O₂), and carboxylesterase were significantly decreased. In contrast, catalase and anti-fungal activities were increased after fungal exposure compared to the control. The activity of acetylcholinesterase, which hydrolyses the important neurotransmitter acetylcholine, also decreased after fungal application compared to the control. Survival of ants was also significantly reduced after fungus infection compared to the control. Our findings help to understand the influence of M. anisopliae on the behavior and physiology of S. invicta, which will help in the management of S. invicta using the EPF M. anisopliae.

Southern red mite, Oligonychus ilicis McGregor (Acari: Tetranychidae), is an important polyphagous spider mite pest that causes economic damage to many ornamentals, coffee, and fruit crops. Blueberry growers in the Southeastern United States, including Florida and Georgia, have experienced severe losses due to outbreaks of O. ilicis. Predatory mites are an important management tool used for controlling spider mites; however, predators have not been studied and successfully evaluated in blueberry systems. Amblyseius swirskiiAthiasHenriot, Phytoseiulus persimilis Athias-Henriot, and Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) are among the most economically important arthropod agents used in augmentative biological control worldwide.To evaluate the potential of these 3 commercially available predatory mites for use in blueberry plantings, we conducted experiments under controlled laboratory conditions and in the greenhouse. In preliminary laboratory experiments, P. persimilis and N. californicus significantly reduced the number of O. ilicis motile stages below those found in the untreated control, indicating the potential for these 2 predatory mite species to suppress O. ilicis populations. Amblyseius swirskii did not perform well controlling O. ilicis motiles in the laboratory. Under greenhouse conditions, N. californicus and P. persimilis significantly reduced the number of eggs after 7 days of release and the number of motile stages after 14 days of release.This is the first report of using phytoseiid mites to suppress O. ilicis in blueberry systems in the United States. Further studies on predator behavior, feeding preferences, and acaricide compatibility with predators are required to investigate the possibility of using P. persimilis, and N. californicus as biological control agents of O. ilicis in blueberry systems.

Grasshoppers represent a significant biological challenge in Inner Mongolia's grasslands, severely affecting the region's animal husbandry. Thus, dynamic monitoring of grasshopper infestation risk is crucial for sustainable livestock farming. This study employed the Maxent model, along with remote sensing data, to forecast Oedaleus decorus asiaticus occurrence during the growing season, using grasshopper suitability habitats as a base. The Maxent model's predictive accuracy was high, with an AUC of 0.966. The most influential environmental variables for grasshopper distribution were suitable habitat data (34.27%), the temperature-vegetation dryness index during the spawning period (18.81%), and various other meteorological and vegetation factors. The risk index model was applied to calculate the grasshopper distribution across different risk levels for the years 2019–2022. The data indicated that the level 1 risk area primarily spans central, eastern, and southwestern Inner Mongolia. By examining the variable weights, the primary drivers of risk level fluctuation from 2019 to 2022 were identified as accumulated precipitation and land surface temperature anomalies during the overwintering period. This study offers valuable insights for future O. decorus asiaticus monitoring in Inner Mongolia.

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a major pest of wheat (Triticum aestivum L., Poales: Poaceae) across the northern Great Plains of North America. Cephus cinctus has a wide host range, attacking numerous wild grasses and cultivated cereals in crop and grassland habitats, where it is, in turn, attacked by 2 native braconid parasitoids. Quantitative assessments of C. cinctus infestation and parasitism levels in different grass species across the full spectrum of available hosts are important in assessing the extent to which grasslands, or specific constituent grass species, may be reservoirs of pests or parasitoids moving into wheat. We quantified infestation and parasitism levels in over 25,000 stems collected from 17 grass species and wheat spanning 35 sites in central Montana, United States, over 2 yr. Infestation levels in 5 grass species, primarily wheatgrasses, were high (38%–65%) and similar to the levels observed in wheat (55%). In contrast, the majority of grass species (12 of 17) had significantly lower levels of infestation (<10%), suggesting that most grasses are not important reservoirs of C. cinctus. Parasitism levels in highly infested wheatgrasses were, on average, 3 times higher than those in cultivated wheat, suggesting that these grasses could provide important conservation habitat for parasitoids. Future work examining the relative performance of pests and parasitoids in these grasses will be important in gauging their relative value as plant materials to bolster parasitoid conservation in reseeded grassland habitats.

This study determined the seasonal population fluctuation of Myzus cerasi (Fabricius) (Hemiptera: Aphididae) in cherry orchards and the effect of different temperatures on the life-history parameters of these aphids under laboratory conditions. Our field results showed that the population fluctuations and densities of M. cerasi on cherry trees were positively affected by the temperature increase between seasons. Also, our laboratory results showed that M. cerasi survived and reproduced at all temperatures tested under laboratory conditions. Female longevity was observed as 19.00 ± 2.38, 18.72 ± 0.49, and 12.59 ± 0.74 days, and fecundity was 10.14 ± 2.26, 9.36 ± 0.59, and 7.27 ± 0.84 offspring/female at 20, 25, and 30 °C, respectively. Although the highest net reproductive rate (R₀) was observed numerically at 25 °C (7.80 offspring/female), there was no significant difference compared to 20 °C (7.10 offspring/female).The highest intrinsic rate of increase (r) and the highest finite rate of increase (λ) were calculated at 30 °C (0.15 ± 0.01 and 1.16 ± 0.01 day^–1, respectively), and there was no significant difference compared to 25 °C.The mean generation time (T) of M. cerasi showed a significant difference at all temperatures tested and decreased from 22.59 ± 0.33 days at 20 °C to 12.78 ± 0.37 days at 30 °C. Consequently, our results revealed that the seasonal population fluctuation and the life history of M. cerasi in the field and laboratory conditions were affected significantly by different temperatures. Our data obtained in the field and the laboratory will contribute to the understanding of M. cerasi biology and to the management of the pest.

The Queensland fruit fly, Bactrocera tryoni (FROGGATT) (Diptera: Tephritidae), is a crop pest of global economic importance because of its wide range of hosts and its invasiveness capacities. To develop a novel integrated and sustainable crop protection, we have investigated the insecticidal properties of different varieties of kava (Piper methysticum [FROST]) extracted by two methods and the attractive effects of six plant volatiles identified from B. tryoni host plants to female, mated or not. We did not identify any significant insecticidal effect of the traditional Pacific kava plant at the tested concentrations. Among mated females, ethyl acetate compared to the no odor control elicited the highest attraction (87%, of which 60% for this odor), while ethyl butyrate was preferred compared with ethyl acetate in dual choice assays. Flies' preferences for specific odors depended on their mating status and the odor landscape they were confronted with. Combination with the commercial ingestion insecticide (Success 4: spinosad, 480 g/l, Dow AgroSciences, Valbonne, France) with the plant volatiles were tested to detect an increase in mortality related to the addition of an attractant. The 2-heptanone slightly showed a tend to increase the attractiveness of mated females within 4-6 h to the food bait, but the results were not statistically significant after 8 h. Further tests should be performed with other concentrations or mixtures of the identified host plant volatiles to develop a strong lure and kill strategy.

La Mouche des Fruits du Queensland, Bactrocera tryoni (FROGGATT) (Diptera, Tephritidae), est un ravageur des cultures d'importance économique mondiale en raison de sa large gamme d'hôtes et de ses capacités invasives. Pour développer une nouvelle protection intégrée et durable des cultures, nous avons étudié les propriétés insecticides de différentes variétés de Kava (Piper methysticum [FROST]) extraites par deux méthodes et les effets attractifs de six volatils d'origine végétale identifiés à partir de plantes-hôtes de B. tryoni sur les femelles, accouplées ou non. Nous n'avons pas identifié d'effet insecticide significatif de la plante traditionnelle Kava du Pacifique aux concentrations testées. Chez les femelles accouplées, l'acétate d'éthyle, comparé au témoin sans odeur, a suscité la plus forte attraction (87%, dont 60% pour cette odeur) et le butyrate d'éthyle a été préféré à l'acétate d'éthyle dans les tests à l'olfactomètre enY. Les préférences des mouches pour des odeurs spécifiques dépendaient de leur statut d'accouplement et du paysage olfactif auquel elles étaient confrontées. La combinaison de l'insecticide commercial d'ingestion (Success 4: spinosad, 480 g/L, Dow AgroSciences, Valbonne, France) avec les molécules volatiles d'origine végétale a été testée pour détecter une augmentation de la mortalité liée à l'ajout d'un attractif. Le 2-heptanone a augmenté l'attraction des femelles accouplées vers l'appât alimentaire, mais les résultats n'étaient pas statistiquement significatifs. D'autres tests doivent être effectués avec d'autres concentrations ou mélanges de substances volatiles de la plante-hôte identifiée afin de développer une stratégie d'attraction fatale efficace.

For non-native insects that are economically damaging, understanding the drivers of range expansions and contractions is important for forecasting pest pressure. The invasion of the redbanded stink bug, Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae), reached Louisiana, United States, in 2000, after which the northern range limits of this species have fluctuated annually. Low winter temperatures have been implicated as a major driver of this pattern, but the importance of cold temperatures—or other abiotic factors—for the persistence of this pest over large geographic scales are incompletely understood. We coupled occurrence data of P. guildinii with climatic data to investigate trends in P. guildinii presence in relation to winter temperatures and develop species distribution models, forecasting habitat suitability based on current and future climatic scenarios. Our results show that (i) some P. guildinii persisted in locations where ambient temperatures reached –12°C, (ii) overwintering temperatures drive P. guildinii range dynamics, and (iii) with intermediate projections of climatic warming, northward expansion by P. guildinii in North America is likely to be minimal. While the northern extent of P. guildinii's range may now be largely realized in North America, our results suggest that increased frequency of mild winters could reduce interannual fluctuations of P. guildinii and enable it to become a more consistent economic concern for soybean growers throughout the Midsouth region of the United States.

The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a polyphagous pest native to the Americas. It first invaded Japan in July 2019, and the most damaged crop in this region to date has been maize. To determine pest control strategies, the range of crops potentially damaged by S. frugiperda in Japan should be identified. In this study, the effects of 8 major crops in Japan—forage maize Zea mays subsp. mays, sugarcane Saccharum officinarum, forage and edible rice Oryza sativa subsp. japonica, soybean Glycine max, eggplant Solanum melongena, green bell pepper Capsicum annuum var. grossum, sweet potato Ipomoea batatas, and taro Colocasia esculenta—on the development of S. frugiperda were analyzed by feeding leaves of domestic cultivars during larval stage. Spodoptera frugiperda developed from hatching to adulthood and laid eggs in all 7 treatments, except for taro. However, among them, only soybean showed comparable developmental suitability to maize. Therefore, its oviposition preference for maize and soybean was examined using further nonchoice and choice tests. In the nonchoice test, the number of egg masses oviposited for 3 days on soybean plants was significantly less than that on test containers, while that on maize was comparable to that on containers. These findings can explain partly why major damage has been limited to maize in Japan.

The number, timing, and fitness of colonizing parasitoids in fields of ephemeral crops often depend on factors external to the fields. We investigated cereal aphid parasitism in 23 winter wheat fields using sentinel plants infested with bird cherry-oat aphids, Rhopalosiphum padi (L.) (Hemiptera: Aphididae), and we investigated the effect of parasitoids on cereal aphid population growth using exclusion and parasitoid-accessible cages infested with bird cherry-oat aphids. Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae), Aphelinus nigritus (Howard) (Hymenoptera: Aphelinidae), and Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae), in decreasing order of abundance, parasitized R. padi on sentinel plants. The mean percent parasitism in parasitoid-accessible cages was 5.2% in autumn and 35.0% in spring. Aphid population intensity was greater in complete exclusion than in parasitoid-accessible cages. Measures of landscape composition and configuration were quantified, and aphid parasitism in autumn by L. testaceipes and A. nigritus was positively associated with % landcover by summer crops and patch density. Parasitism by both species was negatively associated with contagion and % woodlands. Parasitism during spring was positively associated with % grassland and fractal dimension and negatively associated with % canola. The number of braconid mummies per sentinel plant was positively correlated to the number of braconid mummies on wheat stems from parasitoid-accessible cages. Results indicate that cereal aphid mortality caused by parasitoids and their ability to exert effective biological control is related to landscape structure. Comparing this study to an earlier study in the same agroecosystem demonstrated temporal stability of the landscape influence on aphid parasitism by L. testaceipes in winter wheat.

As large cities begin to overrun their landfill capacities, they begin to look for alternative locations to handle the waste stream. Seeing an opportunity to bring in revenue, rural communities offer to handle municipal waste in their landfills. However, many rural communities are also places of agricultural production, which are vulnerable to attacks by invasive insect species, which could be present in green yard waste, the component of municipal waste most likely to contain agriculturally harmful insect species. We used environmental DNA (eDNA) to determine whether green yard waste could be a pathway for invasive insect species to enter and establish in the landfill-receiving agricultural community. We identified several target species that could be in green yard waste coming from Vancouver, BC, Canada, to Central Washington State, USA. We sampled green yard waste from 3 sites every 2 weeks from June to October in 2019 and 2020. DNA was extracted from the nearly 400 samples and subjected to amplification with COI barcoding primers followed by sequencing to identify target insects in the samples. Sequence analyses identified 3 species from the target list: 2 species that are pests of deciduous tree fruits and a generalist root-feeding crop pest. This eDNA technique was useful in identifying potential invasive species in green yard waste and may prove to be an important tool informing policy on the movement of biological material across borders and stemming the spread of invasive species.

Grass buffers are commonly planted along crop borders to filter nutrient and pesticide runoff. These buffers also provide food and shelter for beneficial and herbivorous arthropods and can serve as corridors for their movement into neighboring crops. Mowing is a common maintenance practice to control woody plants in these buffers. Field experiments were conducted to determine whether mowing influences the movement of arthropods into neighboring soybean plantings (Glycine max L) and impacts their abundance in corn (Zea mays var. indentata) the following spring. Results showed that mowing had varying effects on the abundance of herbivores, saprovores, parasitoids, and predators, particularly in the grass buffers. Aerially active arthropods in the plant canopy were more adversely affected by mowing than surface-dwelling arthropods. Mowing significantly reduced grasshopper (Orthoptera: Acrididae) density in the buffers, but did not trigger their movement into adjoining soybean fields. Parasitoids, predators, and thrips (Thysanoptera: Thripidae) were dissimilarly affected by mowing, and their responses were influenced by grass type. Altogether, these findings indicate that mowing did not cause notable movement of arthropods from grass buffers into adjoining crops and had minimal effects on the community of beneficial arthropods the following spring. Also, there were no differences in the level of insect feeding injury in crop fields next to mowed and unmowed buffers.

The brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae) (BPH), is a major, regionally migratory pest of rice in Asia. Despite intensive migratory studies, the seasonal migratory pattern of this species in the year-round breeding region (i.e., Hainan Island) remains largely unknown. To understand the migration dynamics, we conducted relevant research based on BPH light trap catches on Hainan in 2017–2022. Results showed that the occurrence dynamics of BPH in Hainan oscillated in different years and seasons. Overall, there are 4 migration peak periods on Hainan, with outbound peak periods in April–May and August–September and inbound peak periods in June and October. Trajectory and wind fields showed that in August–September, Hainan had complex meteorological conditions, and the outbound paths of BPH were variable, mainly landing in southeastern Guangxi and southwestern Guangdong. In contrast, April–May was influenced by southeasterly winds, with a wider outbound range and a further distance, landing along northeastern Vietnam from west to east toward Guangxi and Guangdong areas with time. Wind-rain fields, trajectory, and hydrogen isotope showed that in June, southwesterly winds transported BPH northward from the Indochina peninsula, where it was hindered by rainfall in the Leizhou Peninsula area and the migrants will be “rained out” into Hainan. Identically, in October, the interactions between northeasterly winds and rainfall belts on the southwest shore of Hainan increased the opportunities for BPH to migrate southward to reach Hainan. Our results suggest that Hainan is not only an important source of BPH migrating from East Asia but also plays the role of a bridge.

Graphical Abstract

The Douglas-fir twig weevil (Cylindrocopturus furnissi Buchanan) (Coleoptera: Curculionidae) has recently emerged as a significant pest of Christmas trees grown in the Pacific Northwest United States. The larvae girdle and disfigure twigs, which adversely affects tree marketability. Trees produced for export are also routinely destroyed for phytosanitary reasons when C. furnissi is discovered at border crossings. Due to historically being a sporadic and benign pest on planted and natural Douglas-fir (Psuedotsuga menziesii), there is a lack of chemical management options. In laboratory experiments, we assessed the knockdown effects (ability to kill or incapacitate) of 4 insecticides commonly used on Christmas trees: one assay tested knockdown after direct contact for 24 h, and the other assay tested knockdown after being allowed to feed on treated twigs with 2 days, 7 days, and 14 days residuals. Concurrently, we monitored temperature and adult C. furnissi emergence at a noble fir bough farm for 2 years to estimate the ideal degree-day window for applying insecticides. Bifenthrin and esfenvalerate knocked down all weevils on contact within just 4 h, whereas chlorpyrifos and acephate failed to achieve 100% knockdown within 24 h. Only acephate failed to knock down more weevils than the control (water) after feeding on treated twigs, regardless of the insecticide residue age. Degree-day modeling revealed a variable emergence window between the 2 years but 50% of adult emergence occurred between approximately 1,000–1,100 degree days (1st January, 50 °F (10 °C), single sine). Future work should assess the resulting management recommendation: apply bifenthrin or esfenvalerate once annually just after 1,000 growing degree days for 2 or more years prior to harvest.

Predatory mites biologically control a range of arthropod crop pests and are often central to agricultural IPM strategies globally. Conflict between chemical and biological pest control has prompted increasing interest in selective pesticides with fewer off-target impacts on beneficial invertebrates, including predatory mites. However, the range of predatory mite species included in standardized pesticide toxicity assessments does not match the diversity of naturally occurring species contributing to biocontrol, with most testing carried out on species from the family Phytoseiidae (Mesostigmata). Here, we aim to bridge this knowledge gap by investigating the impacts of 22 agricultural pesticides on the predatory snout mite, Odontoscirus lapidaria (Kramer) (Trombidiformes: Bdellidae). Using internationally standardized testing methodologies, we identified several active ingredients with minimal impact on O. lapidaria mortality, including Bacillus thuringiensis, nuclear polyhedrosis virus, flonicamid, afidopyropen, chlorantraniliprole, and cyantraniliprole, which may therefore be good candidates for IPM strategies utilizing both chemical and biological control. Comparison of our findings with previous studies on Phytoseiid mites reveals important differences in responses to a number of chemicals between predatory mite families, including the miticides diafenthiuron and abamectin, highlighting the risk of making family-level generalizations from acute toxicity assessments. We also tested the impacts of several pesticides on a second Bdellidae species (Trombidiformes: Bdellidae) and found differences in the response to chlorpyrifos compared with O. lapidaria, further highlighting the taxon-specific nature of nontarget toxicity effects.

A major challenge to area-wide management of coffee berry borer (Hypothenemus hampei Ferrari) (Coleoptera: Scolytidae) is understanding how a heterogeneous coffee-growing landscape affects coffee berry borer population dynamics across temporal and spatial scales. We examined coffee phenology, weather, coffee berry borer flight activity, infestation, coffee berry borer position within the fruit, and management across 14 commercial coffee farms from 2016 to 2018 on Hawaii Island to characterize variation among districts and elevations. Here we aim to determine whether the timing of pesticide applications might be optimized based on specific locations. We observed larger populations of coffee berry borer at low-elevation farms and in the Kona district compared to mid- and high-elevation farms and the Ka'u district. Temperature, relative humidity, and rainfall all differed significantly across districts and elevations. We also observed a trend of higher fruit production at low-elevation farms compared to high-elevation farms, and differences in the timing of fruit development. Infestation increased with higher pest pressure and air temperatures and reduced fruit availability early and late in the season. Lastly, the timing and number of management interventions varied among districts and elevations. Combining information on trap catch, infestation, coffee berry borer position, and plant phenology, we present an optimized pesticide spray schedule for each location and find that the number of sprays could be reduced by 33–75% in comparison to the existing integrated pest management recommendations while maintaining effective control. Implementing a coordinated area-wide approach refined by small-scale optimization will lead to improved management of coffee berry borer on individual farms and a reduction in pest pressure across the coffee-growing landscape.

Helicoverpa armigera Hübner (Lepidoptera: Noctuidae; Hübner) is the major insect pest of pigeon pea [Cajanus cajan; Fabales: Fabaceae; (L.) Millspaugh] worldwide. Research to develop pest management strategies for H. armigera in pigeon pea has focused heavily on developing less susceptible cultivars, with limited practical success. We examined how pigeon pea crop stage influences plant susceptibility to H. armigera using a combination of glasshouse and laboratory experiments. Plant phenology significantly affected oviposition with moths laying more eggs on flowering and podding plants but only a few on vegetative plants. Larval survival was greatest on flowering and vegetative plants, wherein larvae mostly chose to feed inside flowers on flowering plants and on the adaxial surface of expanding leaves on vegetative plants. Larval survival was poor on podding plants despite moths laying many eggs on plants of this stage. When left to feed without restriction on plants for 7 days, larvae feeding on flowering plants were >10 times the weight of larvae feeding on plants of other phenological stages. On whole plants, unrestricted larvae preferred to feed on pigeon pea flowers and on expanding leaves, but in no-choice Petri dish assays H. armigera larvae could feed and survive on all pigeon pea reproductive structures. Our results show that crop stage and the availability of flowers strongly influence pigeon pea susceptibility to H. armigera. An increased understanding of H. armigera-pigeon pea ecology will be useful in guiding the development of resistant varieties and other management tactics.

Insecticides prevent or reduce insect crop damage, maintaining crop quality and quantity. Physiological traits, such as an insect's feeding behavior, influence the way insecticides are absorbed and processed in the body (toxicokinetics), which can be exploited to improve species selectivity. To fully understand the uptake of insecticides, it is essential to study their total uptake and toxicokinetics independent of their toxic effects on insects. We studied the toxicokinetics (TK) of insecticidally inactive test compounds incorporating agro-like structural motifs in larvae of the Egyptian cotton leafworm (Spodoptera littoralis, Lepidoptera), and their distribution across all biological matrices, using laboratory experiments and modeling. We measured Spodoptera larval behavior and temporal changes of whole-body concentrations of test compounds during feeding on treated soybean leaf disks and throughout a subsequent depuration period. Differences in the distribution of the total quantities of compounds were found between the biological matrices leaf, larva, and feces. Rate constants for uptake and elimination of test compounds were derived by calibrating a toxicokinetic model to the whole-body concentrations. Uptake and elimination rate constants depended on the physicochemical properties of the test compounds. Increasing hydrophobicity increased the bioaccumulation potential of test compounds. Incomplete quantities in larval matrices indicated that some compounds may undergo biotransformation. As fecal excretion was a major elimination pathway, the variable time of release and number of feces pellets led to a high variability in the body burden. We provide quantitative models to predict the toxicokinetics and bioaccumulation potential of inactive insecticide analogs (parent compounds) in Spodoptera.

Graphical Abstract

On-farm losses of peanuts (Arachis hypogaea L., Fabales: Fabaceae) pose a persistent threat to the sustainable production and value of peanuts in the United States. This study presents empirical data on the spatial distribution of subterranean insect pests and various quality aspects of peanuts. Surveys were conducted in 20 randomly selected peanut fields in 10 counties in Northeast, Southeast, and Southwest Georgia. The primary insect pests found in Georgia's peanut production counties were Pangaeus bilineatus (Say), Elasmopalpus lignosellus (Zeller), and Diabrotica undecimpunctata Howardi. In the northeast counties, a high prevalence of P. bilineatus led to a significant increase in insect-damaged pods (%IDP), insect-damaged kernels (%IDK), discolored kernels (%DK), pod weight loss (%PWL), and kernel weight loss (%KWL). Similarly, southeast counties had a high %DK, cracked pods (%CP), and E. lignosellus infestation. In southwest counties, predominantly high D. undecimpunctata infestations resulted in the highest %IDP. Moisture content (%MC) was excessively high in all the counties (22.19%–23.17%). Preharvest aflatoxin contamination in peanuts was prevalent across all studied locations, particularly in counties with a high incidence of P. bilineatus and may cause increased risk in aflatoxin levels along the supply chain. Nevertheless, the diverse regional abundance of insect pests and the widespread presence of aflatoxins in Georgia's peanut fields offer valuable insights for developing integrated pest management strategies targeting subterranean insect pests. This is especially crucial in addressing the impact of P. bilineatus, E. lignosellus, and D. undecimpunctata on aflatoxins content of peanuts and determining the pathway for mitigation of aflatoxin contaminations in peanuts at harvest.

Male cerambycid beetles of the large subfamilies Cerambycinae and Lamiinae produce aggregation-sex pheromones that attract both sexes. The pheromones of many species are conserved among both closely related species (e.g., congeners) and more distantly related species (e.g., different subfamilies), including those endemic to different continents. This parsimony in pheromone structures suggests that multiple species may be attracted to traps baited with blends of pheromones, and such blends are finding use in delineating geographic ranges of native species and in surveillance programs for incursions of exotic species. Here, we present the results of a field experiment conducted at multiple sites in Iowa that tested the effects of deploying ethanol lures in tandem with a 6-component blend of common pheromone components for cerambycine and lamiine species and a 5-component blend that specifically targeted lamiines. Eight cerambycine species showed significant treatment effects, most of which were attracted to the 6-component blend, and ethanol increased attraction for half of these species. Two cerambycine species were attracted only by ethanol. Seven lamiine species were attracted by the lamiine-specific blend, alone or when combined with ethanol, and 3 of these species also were attracted to the 6-component blend. Taken together, these findings provide further evidence that carefully crafted blends of pheromones can be used to monitor the presence or abundance of multiple cerambycid species. Ethanol either increased the number of beetles attracted by pheromones or had no effect, so there is no apparent downside to deploying ethanol lures in combination with pheromones.

The southern pine beetle, Dendroctonus frontalis Zimmermann is an important mortality agent of Pinus in the eastern United States of America where it commonly shares hosts with the black turpentine beetle, Dendroctonus terebrans (Olivier), which infrequently kills trees. Unlike D. frontalis, which must kill its hosts to become established in the bark and reproduce, D. terebrans can occupy living hosts as a parasite. Olfactory mechanisms whereby D. frontalis initially locates hosts have not been demonstrated, whereas D. terebrans responds strongly to host odors. Because D. terebrans produces frontalin, the primary aggregation pheromone component for D. frontalis, and commonly arrives on hosts prior to D. frontalis, it has been hypothesized that D. terebrans pheromone components can mediate D. frontalis location of suitable, living trees. We assessed this possibility with studies of the semiochemical interactions between D. frontalis and D. terebrans. Coupled gas chromatography-electroantennographic detection analyses indicated that D. terebrans produces nine different olfactory stimulants for D. frontalis, nearly all of them known semiochemicals for D. frontalis. A trapping experiment designed to address the potentially confounding influence of lure contamination confirmed that the D. terebrans pheromone component exo-brevicomin enhances attraction of D. frontalis and thus could be an attractive kairomone. In ambulatory bioassays, male D. frontalis were strongly attracted to odors of frass of solitary female and paired D. terebrans, indicating their attraction to the naturally occurring semiochemicals of D. terebrans. Cues from D. terebrans may influence host and mate-finding success of D. frontalis and, thereby, the latter's virulence.

Spruce beetle, Dendroctonus rufipennis (Kirby) (Coleoptera: Curculionidae), is the most destructive pest of mature spruce (Picea) in western North America. Recent outbreaks in Alaska and other western US states highlight the need for tools to protect Picea from D. rufipennis. The primary antiaggregation pheromone of D. rufipennis (3-methylcyclohex-2-en-1-one, MCH) and various combinations of potential repellents (1-octen-3-ol, exo-brevicomin, endo-brevicomin, ipsdienol, ipsenol, limonene, and verbenone) were tested for their ability to disrupt the response of D. rufipennis to attractant-baited multiple-funnel traps. Two assays were conducted on the Kenai Peninsula, Alaska, in June and July 2021. All treatments significantly reduced the mean number of D. rufipennis caught compared to the baited control. No other significant differences were observed among treatments. Informed by these and other data, tree protection studies were established in Lutz spruce, Picea × lutzii, on the Kenai Peninsula in 2022 and in Engelmann spruce, Pi. engelmannii, in the Uinta Mountains, Utah, in 2021. All experimental trees were baited with frontalin. Repellent treatments included MCH (SPLAT MCH, ISCA Inc., Riverside, CA, USA) and at least 1 additional repellent combination. In Alaska, all treatments significantly reduced colonization (strip attacks + mass attacks) and mortality of individually treated Pi. × lutzii and all Picea within 11.3-m radius of each treated Pi. × lutzii compared to the control. In Utah, all treatments except for SPLAT MCH + octenol significantly reduced colonization compared to the control. Only SPLAT MCH + Acer kairomone blend (AKB) and SPLAT MCH + octenol reduced Pi. engelmannii mortality compared to the control. SPLAT MCH + AKB and SPLAT MCH + acetophenone and green leaf volatiles (PLUS) were the most effective across both studies.The implications of these and other results to the development of an effective semiochemical repellent for D. rufipennis are discussed.

3-Hydroxyhexan-2-one (3-C6-ketol) has emerged as the most conserved pheromone structure within the beetle family Cerambycidae. In this study, we report the sex-specific production of this compound by males of 12 species of South American cerambycid beetles. Males of Chrysoprasis chalybea Redtenbacher and Mallosoma zonatum (Sahlberg) (Tribe Dichophyiini), and Ambonus lippus (Germar), Eurysthea hirta (Kirby), Pantonyssus nigriceps Bates, Stizocera plicicollis (Germar), and Stizocera tristis (Guérin-Méneville) (Elaphidiini) produced 3R-C6-ketol as a single component, whereas males of Neoclytus pusillus (Laporte & Gory) (Clytini), Aglaoschema concolor (Gounelle), Orthostoma abdominale (Gyllenhal) (Compsocerini), Dorcacerus barbatus (Olivier), and Retrachydes thoracicus thoracicus (Olivier) (Trachyderini) produced 3R-C6-ketol, along with lesser amounts of other compounds. In field trials testing 8 known cerambycid pheromone compounds, C. chalybea, E. hirta, and R. t. thoracicus were attracted in significant numbers to traps baited with 3-C6-ketol. A second field experiment provided support for the strategy of using the attraction of cerambycid species to test lures as a method of providing leads to their likely pheromone components. Because both sexes are attracted to these aggregation-sex pheromones, live beetles can be obtained from baited traps to verify they produce the compound(s) to which they were attracted, that is, that the compounds are indeed pheromone components.

Climate change involves changes in the pattern of temperature fluctuations and the frequency and magnitude of thermal extremes. It is essential to investigate how insects respond to increased temperature variations, especially for species that usually experience diel temperature variations extending to thermal performance limits. To explicitly elucidate the effects of sizes of amplitudes of temperature variations, we used daily alternating temperatures with an equivalent mean of 28 °C to investigate the impact of different fluctuation amplitudes (± 0 °C, ± 2 °C, ± 4 °C, and ± 6 °C) across permissive temperature regimes on the performance of Spodoptera litura Fabricius, a highly destructive polyphagous pest of crops and vegetables in tropical and temperate climates. Amplitudes of temperature fluctuations significantly affected developmental durations, adult life spans, pupal weights, fecundity, and fertility of S. litura. The survival rates from the egg stage to the adult eclosion did not differ significantly across different temperature treatments. The developmental durations of individual life cycles significantly increased with larger amplitudes in 3 fluctuating temperature treatments.The pupal weight was significantly lower and the adult life span was significantly shorter in the ± 6 °C treatment in all treatments. Fecundity and fertility were significantly reduced in the ± 6 °C treatment, making the continuation of generations nearly impossible. The results should provide critical information for understanding the ecology of this widespread pest under diel, seasonal, and global climate changes.

Rhodesgrass mealybug, Antonina graminis Maskell (Hemiptera: Pseudococcidae), is an emerging pest of turfgrass in Georgia golf course putting greens. Because the feeding damage of A. graminis severely affects the aesthetics of the putting surface, it is necessary to understand the phenology of A. graminis on putting greens. To develop management strategies, the temporal emergence of crawlers is determined; however, a sampling tool for A. graminis crawlers on putting greens has not been developed. Thus, the objectives were to determine (i) the phenology of A. graminis and turfgrass quality and (ii) the best trap types for sampling crawlers on the putting greens in Georgia. From 2019 to 2022, 10–20 turfgrass plugs were sampled from the putting greens at biweekly intervals from the spring to fall. The numbers of crawlers, sessile nymphs, and adults of A. graminis were quantified from these plug samples. To determine the best trap types for sampling crawlers, 6 trap types were evaluated on the putting greens in 2021 and 2022. In the spring, the A. graminis densities remained low until June or July, then all stages of A. graminis increased. In the late fall and winter, A. graminis densities declined and remained low. The turfgrass quality improved temporally from April to June but progressively declined from the mid-to-late summer to fall. Significantly greater numbers of crawlers were sampled in the paper-folded sticky card method than in the turfgrass plug method. Thus, sticky traps could be used to sample crawlers for pest management decision.

To better understand how frequently pollinators visit the most popular annuals and the variation among cultivars, we evaluated 3–6 cultivars, each of petunia, impatiens, begonia, geranium, pansy, and New Guinea impatiens. These 6 annuals account for 46.6% of all garden center annual flower sales in the United States. Flower visits by honey bees, bumble bees, syrphids, other Diptera and other Hymenoptera, combined, varied 3 to 10-fold among cultivars within each of the 6 popular annuals. Begonia and impatiens were visited more frequently by pollinators than pansy, petunia, NG impatiens, and geranium. The 4 most visited cultivars, begonia ‘Cocktail Brandy’, begonia ‘Ambassador Rose Blush’, impatiens ‘Accent Coral’, and impatiens ‘Super Elfin XP White’ attracted as many pollinators as a benchmark annual, marigold ‘Alumia Vanilla Cream’, considered as moderately attractive to pollinators. Some conclusions from this research may be helpful for homeowners, landscapers, growers, and breeders. First, the most popular annual flowers are not a good choice for the purpose of attracting and supporting pollinators. However, the large variation among cultivars provides an opportunity to select cultivars that are more attractive to pollinators, particularly for begonia and impatiens. If the most pollinator-visited cultivars of begonia and impatiens are labeled and promoted as such, it would be beneficial to pollinators in urban and suburban landscapes in the USA and Europe, where they comprise 10%–20% of all annual flowers purchased from garden centers.

We investigated the expression of 4 cytochrome P450 genes (CYP4G19, CYP6J1, CYP6K1, and CYP4C21) in 4 field-collected strains (WM, RG386, CDR, and Ryan) of the German cockroach, Blattella germanica (L.), collected from California. The UCR susceptible strain was used as a comparison. Topical assays using a diagnostic dose (3× LD₉₅) of deltamethrin revealed decreased sensitivity in all field-collected strains with mortality ranging from 0% to 58%, and the addition of PBO before deltamethrin treatment increased mortality to 52.5%–87.5%. Using qPCR to investigate the expression levels of CYP4G19, CYP4C21, CYP6J1, and CYP6K1, we found that only CYP6K1 was significantly overexpressed (2.1–5.8× higher) in all field-collected strains when compared to the UCR strain. Next, we investigated the role of the CYP6K1 gene by performing gene knockdown using RNAi. After dsCYP6K1 treatment, the expression levels of CYP6K1 in WM and Ryan strains were significantly reduced (P < 0.01) by 91%–94% vs. those treated with dsEGFP (control) on the third and sixth day posttreatment. RG386, CDR, and Ryan strains were more susceptible compared to their respective controls to topically applied deltamethrin 6 days after treatment with dsCYP6K1. This study provides evidence of the involvement of the P450 CYP6K1 gene in pyrethroid resistance in some populations of German cockroaches.

Despite providing important ecosystem services, termites are also serious pests of wooden structures. Termites are highly adaptive organisms that cause concern as an invasive species. Predictions of the future spread of their distribution range due to factors such as climate change, urban growth, and global trade present new challenges to our capacity to protect our wood and wood-based materials and structures effectively. Reticulitermes grassei Clément, 1978 (Blattodea: Rhinotermitidae) is a subterranean termite native to the Iberian Peninsula and France, whose global distribution has widened over recent years. This article updates the distribution range of this species, confirming its identification in the Azores, Madeira, and Morocco through molecular analysis. The origin and consequences of these putative invasive populations are discussed in light of previously available data. The resulting network showed a highly structured base consisting of many haplotypes from the southern and southwestern Iberian Peninsula (Spain and Portugal), including those from Morocco (in natural landscapes) and Switzerland (in infrastructures). The more derived part of the network includes the haplotypes from southwest France, the northwest Iberian Peninsula, the United Kingdom, Azores, and Madeira, the last 3 being linked probably to human-mediated transportation events. The potential impacts of invasive subterranean termite populations expanding into new regions are concerning, especially in urban environments, and remain uncertain in natural areas. The challenges posed by these termites could be especially worrying in island ecosystems. Hence, it is crucial to implement early warning systems and monitoring programs in regions susceptible to subterranean termite invasions.

Graphical Abstract

Isocycloseram is a new insecticide in the isoxazoline class that targets insect GABA-gated chloride channels. In this study, we evaluated a cockroach gel bait formulation containing 1% isocycloseram against a susceptible strain (UCR) and 5 field-collected strains (WM, RG386, Ryan, CDR, and SY) of the German cockroach, Blattella germanica (L.) (Blattodea: Ectobiidae), and compared it with several commercial insecticide baits in the laboratory. Using the Ebeling choice box method, we also tested a residual deposit of an SC formulation of isocycloseram against the UCR, RG386, and Ryan strains. The isocycloseram bait was among the fastest-performing treatments against adult males (mean survival time: 0.9–2.7 days) and mixed stages and sexes (mean survival time: 1.4–5.4 days) across all strains. Secondary transfer effects of the bait were demonstrated in the UCR strain by exposing new adult males to individuals killed by direct bait treatment. Physiological resistance was not detected in the WM, CDR, and RG386 strains with topical treatment of a diagnostic dose (3× LD₉₅) of isocycloseram developed using the UCR strain. However, topical assays revealed resistance ratios (RR₅₀) of 1.6 and 3.0× in the Ryan and SY strains, respectively. The performance of a 0.05% isocycloseram residual application against the Ryan strain was improved with the addition of piperonyl butoxide.

In the Americas, transgenic crops producing insecticidal proteins from Bacillus thuringiensis Berliner (Bt, Bacillales: Bacillaceae) have been used widely to manage fall armyworm (FAW, Spodoptera frugiperda [J.E. Smith]). As resistance to Cry1 single-gene Bt maize (Zea mays L.) rapidly evolved in some FAW populations, pyramided Bt maize hybrids producing Cry1, Cry2, or Vip3Aa proteins were introduced in the 2010s. We examined field-evolved resistance to single- and dual-protein Bt maize hybrids in 2 locations in southeastern Brazil, where plant damage by FAW larvae far exceeded the economic threshold in 2017. We collected late-instar larvae in Cry1A.105 + Cry2Ab and Cry1F maize fields and established 2 FAW populations in the laboratory. The F₁ offspring reared on the foliage of Bt and non-Bt maize plants (Cry1A.105 + Cry2Ab and Cry1F) showed neonate-to-adult survival rates as high as 70% for both populations. There was no significant difference in the life-table parameters of armyworms reared on non-Bt and Bt maize foliage, indicating complete resistance to Cry1A.105 + Cry2Ab maize. Larval survival rates of reciprocal crosses of a susceptible laboratory strain and the field-collected populations indicated nonrecessive resistance to Cry1F and a recessive resistance to Cry1A.105 + Cry2Ab maize. When relaxing the selection pressure, the armyworm fitness varied on Cry1A.105 + Cry2Ab and non-Bt maize; the resistance was somewhat stable across 12 generations, without strong fitness costs, although one of the lines died confounded by a depleted-quality, artificial rearing diet. To our knowledge, this is the first report documenting the practical resistance of FAW to a pyramided Bt crop. We discuss the implications for resistance management.

Transgenic crops producing Bacillus thuringiensis (Bt) toxins are commonly used for controlling insect pests. Nearby refuges of non-Bt host plants play a central role in delaying the evolution of resistance to Bt toxins by pests. Pervasive fitness costs associated with resistance, which entail lower fitness of resistant than susceptible individuals in refuges, can increase the ability of refuges to delay resistance. Moreover, these costs are affected by environmental factors such as host plant suitability, implying that manipulating refuge plant suitability could improve the success of the refuge strategy. Based on results from a previous study of Trichoplusia ni resistant to Bt sprays, it was proposed that low-suitability host plants could magnify costs. To test this hypothesis, we investigated the association between host plant suitability and fitness costs for 80 observations from 30 cases reported in 18 studies of 8 pest species from 5 countries. Consistent with the hypothesis, the association between plant suitability and fitness cost was negative.With plant suitability scaled to range from 0 (low) to 1 (high), the expected cost was 20.7% with a suitability of 1 and the fitness cost increased 2.5% for each 0.1 decrease in suitability. The most common type of resistance to Bt toxins involves mutations affecting a few types of midgut proteins to which Bt toxins bind to kill insects. A better understanding of how such mutations interact with host plant suitability to generate fitness costs could be useful for enhancing the refuge strategy and sustaining the efficacy of Bt crops.

Thrips are devastating pests for various crops, and they can rasp tender leaves, terminal buds, and flowers, which specifically causing huge economic losses to cotton production. However, there is very little knowledge about the species composition of thrips in mainland China, as well as the genetic structure of the thrips populations, particularly in the cotton-producing regions. In this study, thrips were collected from 40 geographical locations at 8 different provinces which representing majority cotton-producing belts in China, and mitochondrial cytochrome oxidase subunit I sequence was used to identify species composition and evaluate the genetic diversity of collected thrips individuals. Based on experimental results proven that overall, 10 and 8 species of thrips were identified in seedling and flowering stage respectively, which is corresponding dominant species are Thrip tabaci (Lindeman) and Frankliniella intonsa (Trybom). Genetically, 24 haplotypes were identified in 310 T. tabaci individuals from 10 locations, and 263 haplotypes were detected in 1,861 F. intonsa individuals from 40 locations. Hap1 (T. tabaci) is the most widely distributed haplotype among all the T. tabaci samples. Likewise, Hap 2 is the most widely distributed and abundant haplotype among all samples of F. intonsa. The genetic differentiation degrees of T. tabaci between SXYC population and other 9 populations were high, but its gene flow in these 10 regions was relatively low, which might be due to geographical barriers. The Mantel tests showed no correlation between genetic distance and geographic distance of the 2 thrip species. Demographic analysis results showed that both T. tabaci and F. intonsa experienced population expansion in China. Taken together, this study identifies the species composition of thrips in major cotton-producing regions at different growth periods and evaluates effects of geomorphology on the geographical distribution of haplotypes of dominant thrips T. tabaci and F. intonsa.

Metarhizium anisopliae is an important class of entomopathogenic fungi used for the biocontrol of insects, but its virulence is affected by insect immunity. We identified a novel FK506 binding protein gene that was differentially expressed between control and Metarhizium-treated Locusta migratoria manilensis. We hypothesized that this protein played an important role in Metarhizium infection of L. migratoria and could provide new insights for developing highly efficient entomopathogenic fungi. We, therefore, cloned the specific gene and obtained its purified protein. The gene was then named FKBP52, and its dsRNA (dsFKBP52) was synthesized and used for gene interference. Bioassay results showed that the mortality of L. migratoria treated with dsFKBP52 + Metarhizium was significantly lower than that of other treatments. Furthermore, immune-related genes (MyD88, Dorsal, Cactus, and Defensin) in L. migratoria treated with dsFKBP52 + Metarhizium showed significant upregulation compared to that treated with Metarhizium only. However, the activities of peroxidase (POD), superoxide dismutase (SOD), and calcineurin (CaN) showed fluctuations.These results suggest that the FKBP52 gene may play a crucial role in the innate immunity of L. migratoria.The effect of its silencing indicated that this immunity-related protein might be a potential target for insect biocontrol.

Graphical Abstract

After feeding on FKBP52 protein, it was found that the survival rate of the FKBP52-only baits was 97.78% by day 10, which was not significantly different (P > 0.05) from the control (98.89%). When treated with M. anisopliae alone, the survival rate decreased with the number of days of treatment, reaching 40% by day 10, which was significantly lower than that of the FKBP52 protein alone and the control group. The survival rate of the locusts decreased rapidly when treated with FKBP52 protein and M. anisopliae, reaching 6.67% by day 10, which was significantly lower than that of the M. anisopliae alone (P < 0.05).The above results showed that the co-treatment of FKBP52 protein and M. anisopliae significantly increased the pathogenicity and insecticidal effect of the treatment on the L. migratoria.

After injection of dsFKBP52, the bioassay results obtained under different treatments showed that injection of the dsFKBP52 killed only 5.56% of L. migratoria, and this was not different from that of the control.The survival rate was 98.89% on the 10th day. Application of M. anisopliae alone decreased the survival rate of L. migratoria to 26.67% on the 10th day after infection. This was significantly lower than that recorded from the injection of dsFKBP52 and the control. The survival rate recorded when M. anisopliae and dsFKBP52 were applied in combination was 64.44%.This was significantly higher than recorded under treatment of M. anisopliae treated alone (P < 0.05). The above results showed that the co-treatment of dsFKBP52 and M. anisopliae significantly enhanced the immune ability of L. migratoria and reduced the pathogenicity of M. anisopliae.

Bombyx mori L. (Lepidoptera: Bombycidae) nucleopolyhedrovirus (BmNPV) is a serious pathogen causing huge economic losses to sericulture. There is growing evidence that the gut microbiota of silkworms plays a critical role in shaping host responses and interactions with viral infection. However, little is known about the differences in the composition and diversity of intestinal microflora, especially with respect to silkworm strain differences and BmNPV infection-induced changes. Here, we aim to explore the differences between BmNPV-resistant strain A35 and susceptible strain P50 silkworm and the impact of BmNPV infection on intestinal microflora in different strains. The 16S rDNA sequencing analysis revealed that the fecal microbial populations were distinct between A35 and P50 and were significantly changed post BmNPV infection in both strains. Further analysis showed that the BmNPV-resistant strain silkworm possessed higher bacterial diversity than the susceptible strain, and BmNPV infection reduced the diversity of intestinal flora assessed by feces in both silkworm strains. In response to BmNPV infection, the abundance of Muribaculaceae increased in P50 and decreased in A35, while the abundance of Enterobacteriaceae decreased in P50 and increased in A35. These results indicated that BmNPV infection had various effects on the abundance of fecal microflora in different silkworm strains. Our findings not only broadened the understanding of host–pathogen interactions but also provided theoretical help for the breeding of resistant strains and healthy rearing of silkworms based on symbiotic bacteria.

The grape berry moth, Paralobesia viteana (Clemens), is an important pest of cultivated grapes in eastern North America. Damage is caused directly by larval feeding of grape clusters and indirectly by increasing fruit susceptibility to fungal and bacterial pathogens. Despite the impact of grape berry moth on grapes being widely recognized, there is a lack of understanding of the influence that different grape cultivars may have on grape berry moth development, reproduction, and population dynamics. In this study, we constructed age–stage 2-sex life tables for grape berry moth fed on 5 grape cultivars: Concord, Niagara, Riesling, Chambourcin, and Vidal, to examine the effects of diet on insect population development, survival, reproduction, and demographic parameters such as net reproductive rate, intrinsic rate of increase, finite rate of increase, and mean generation time. Our findings reveal that grape cultivar significantly influenced the neonate wandering period, larval developmental time, adult and female longevity, pupal weight, adult preoviposition period, oviposition period, mean generation time, age–stage-specific life expectancy, and reproductive value of P. viteana. However, diet type did not affect grape berry moth total fecundity or other demographic parameters. The highest female reproductive value was observed at 30–40 days of age, indicating that control tactics implemented during this time frame would have the greatest impact on reducing population increase. This study provides critical information on the effects of different grape cultivars on grape berry moth development, reproduction, and demography. These insights could lead to the development of management strategies that improve pest control and reduce economic losses in vineyards.

The maize weevil, Sitophilus zeamais Motschulsky, is a hidden pest that presents serious risk to grain quality during postharvest storage. Lipid-derived volatile detection is considered a key reference for early prediction of S. zeamais infestation. However, the exact compositions of fatty acids and volatile organic compounds (VOCs) in S. zeamais-infested wheat are yet to be determined. In this study, we aimed to explore the effect of S. zeamais infestation on lipid metabolism in wheat infested with S. zeamais eggs (4 days), larvae (20 days), pupae (35 days), and adults (45 days). Compared to those in the control group, the activities of lipid oxidation enzymes, such as lipase, lipoxygenase, and alcohol dehydrogenase, increased by 82.73%, 105.12%, and 487.86%, respectively, during the storage period of 1 life cycle of S. zeamais. Additionally, the fatty acid composition of S. zeamais-infested wheat was significantly altered (palmitic acid [1.10-fold], oleic acid [1.07-fold], and linoleic acid [0.95-fold]). Furthermore, 91 VOCs were identified in all wheat samples; then, multivariate statistical analyses categorized these samples into 4 groups: uninfested, longer storage, lightly infested, and heavily infested. Moreover, 31, 26, and 45 potential VOCs were identified to distinguish uninfested wheat from those in the other 3 groups. These results demonstrated that S. zeamais infestation induces an elevation in lipid-related enzymatic activities, which potentially leads to a decrease in lipid content alongside the production of specific VOCs (undecan-4-olide, heptaldehyde, and 2-nonenal).These findings provide novel insights for rapidly identifying grains infested by hidden pests and effectively managing these pests during grain storage.

Graphical Abstract

The Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is a very common stored-product pest. The mature larvae wander around searching for suitable places to pupate, offering an opportunity to control this pest. We evaluated the efficacy of 5 insecticide dusts: Alpine (0.25% dinotefuran, 95% diatomaceous earth [DE]), CimeXa (92.1% amorphous silica gel), DX13 (100% DE), Tempo (1% cyfluthrin), and Tri-Die (1% pyrethrin, 10% piperonyl butoxide, 40% amorphous silica) against P. interpunctella wandering larvae by allowing larvae to pass 1-inch treated band, expose to treated vinyl tiles for 5 min, and expose to treated harborage (with or without the presence of an untreated harborage). A commercially treated harborage product (Nattaro band) served as a positive control in the exposure to the treated harborage test. Tempo was significantly more effective than other insecticide dusts in the 1-inch band and forced exposure tests but caused only 44% and 54% larvae mortality in the 2 tests. In contrast, CimeXa, Tri-Die, and Tempo caused 84%–89% mortality when the larvae were provided with treated harborages. When both treated and untreated harborages were present, Tempo caused a significantly higher mortality and a lower percentage of emerged adults from larvae than Tri-Die, but not significantly more than CimeXa. Deploying Tempo or CimeXa-treated harborages and/or applying insecticide dust directly into the wall crevices, perimeters of the floor, shipping pallets, and other areas where P. interpunctella larvae hide could be an effective method for the management of the wandering stage of P. interpunctella larvae in storage facilities.

Increasing efficiency of data gathering at the landscape scale on the growing number of pests and pathogens threatening forests worldwide has potential to improve management outcomes. Citizen science is expanding, with growing support and utility in environmental and conservation fields. We present a case study showing how citizen science observations can be used to inform research and management of a devastating forest pest. Hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), was introduced to eastern North America, leading to decline and mortality of eastern [Tsuga canadensis (L.) Carrière] (Pinales: Pinaceae) and Carolina hemlock (Tsuga caroliniana Engelmann) trees. Management activities, most notably biological control, rely on observations of A. tsugae phenology to inform the timing of releases and monitoring surveys of their highly synchronized specialist predators. In this article, we outline a citizen science program and report phenological observations on A. tsugae. Additionally, we report data comparing A. tsugae estivation break in Virginia (VA) and NewYork (NY) State, revealing that estivation break is synchronized between NY and VA.This observation is supported by 6 years of citizen scientist observations, showing similar patterns throughout NY, with egg laying shown to be much more variable than estivation break.

Euwallacea fornicatus is an invasive tree pest able to infest healthy plants and cause damage to many host plants. This beetle has become established in several countries where it was introduced. It has now become established in Brazil, and while the original introduction site remains uncertain, there is a possibility of multiple introductions. We report the first evidence for the establishment of E. fornicatus with molecular confirmation, as well as its distribution, and host plants in Brazil. Euwallacea fornicatus has spread to main commercial avocado groves, other monocultures, and native vegetation in the country, and its pest status puts it as a threat, mainly to Brazilian avocado producers.