Corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), is a major insect pest of many agricultural crops in Virginia. Pyrethroids have been the major insecticide class used to control the pest for decades; however, H. zea resistance to pyrethroids has been widely documented in the southeastern and midwestern United States. To assess the pyrethroid susceptibility of H. zea in Virginia, we collected larval populations from the same five locations in 2021 and 2022 and used a quick end user–friendly bioassay to assess survival of larvae after feeding on insecticide-dipped edamame [Glycine max (L.) Merrill] pods. Pyrethroid efficacy varied between years and locations, with some 2021 H. zea populations showing reduced pyrethroid susceptibility, but not in 2022. This variability is most likely influenced by factors such as overwintering survivability in Virginia. Thus, the need for continued annual monitoring is important to track efficacy trends and grower recommendations. The simple bean-dip bioassay could be used as an efficient monitoring tool in the future, with pyrethroid susceptibility determined in 48 h from field collection.

Local fruit orchards have incurred heavy losses due to invasive insects, including the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), in Guizhou Province, China. In our efforts to manage this invasive pest, a laboratory study was conducted to evaluate the response of adult B. dorsalis to an extract of Ageratina adenophora (Spreng.) R.M. King & H. Rob (Gunneridae: Asteraceae). We evaluated the contact toxicity and oviposition-deterrent activity of the extract on adult B. dorsalis, as well as the sublethal effects on survival and reproduction. We found that the A. adenophora extract has significant insecticidal activity, with the 24-h median lethal concentration (LC₅₀) for adults being 26.014 mg/ml. The extract of A. adenophora also showed oviposition inhibition. A residual deterrent effect (28.16%) was evident up to 5 d after treatment. Exposure to the LC₂₅ concentration of the A. adenophora extract caused significant differences in preoviposition and fecundity, decreased adult longevity in the F₀ generation, and decreased egg and pupa survival in the F₁ generation. The levels of carboxylesterase enzyme activity in adults treated with the extract were significantly lower than those in the untreated controls at 12 h and 24 h. This latter phenomenon could perhaps be an adaptive response to the extract that might reduce its toxic effects in B. dorsalis.

Menochilus sexmaculatus F. (Coleoptera: Coccinellidae) is a generalist predator with potential as a biological control candidate for suppressing many insect pests, including the cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae). However, the potential control capacity of M. sexmaculatus on P. solenopsis may depend not only on its fitness and predatory efficacy, but also on the consequences of both conspecific and heterospecific interactions with other individuals that share the same resource. This study investigated the aggressiveness and vulnerability of different life stages of M. sexmaculatus when encountering various stages of M. sexmaculatus or Harmonia axyridis (Pallas). The results showed that M. sexmaculatus could act as predator and/or prey with the presence of conspecific and heterospecific ladybird beetles. The success of predation is affected by the ladybird beetle life stage and, in most cases, young stages of the ladybird beetles were most susceptible to relatively older life stages of ladybird beetles. Predation between M. sexmaculatus/H. axyridis larvae of the same developmental stage was always asymmetric, favoring H. axyridis. Moreover, M. sexmaculatus exhibited intensive aggressiveness toward their own species over heterospecific individuals, but was more vulnerable to H. axyridis than to M. sexmaculatus individuals. Overall, H. axyridis could negatively affect the population densities of M. sexmaculatus by its high aggressiveness and low vulnerability. However, because our study was conducted in an oversimplified and confined area, more research should be conducted under more realistic conditions to explore the impacts of H. axyridis on the population dynamics of M. sexmaculatus.

As a modern orchard management tool, vegetative ground cover can increase biodiversity, enhance the effect of natural enemies, and reduce the amounts of chemical agents used to control pests. This study aimed to investigate the temporal niche relationship between pests and natural enemies in peach orchards (1) planted with flowering plants as a ground cover or (2) with naturally occurring vegetative ground cover or (3) plowed, with the objective of clarifying the conservation effect of peach orchard ground cover on different natural enemies. The results showed that the niche width value of natural enemies in peach orchards planted with the flowering plants was the highest, followed by natural vegetation peach orchards. The ladybird beetle (Coccinellidae) ecological niche width values were the highest in the natural enemy communities of the two types of peach orchards. These results demonstrate that vegetative ground cover in peach orchards can effectively harbor natural enemies and that coccinellids are highly adapted for the ecological environment of the peach orchard.

Chlorantraniliprole, a new anthranilic diamide insecticide, has been commercialized in China since 2008 for controlling several lepidopterans, including rice stem borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae). Chemical control of this pest has become difficult because of its development of resistance to many conventional insecticides. To facilitate chlorantraniliprole resistance monitoring, seedling dip bioassays were conducted in 2013 and 2020 to assess the resistance of 5 field populations of C. suppressalis from Hunan provinces in China. The median lethal toxicity (LC₅₀) of chlorantraniliprole against 3rd–4th instar larvae of field populations ranged from 14.799 to 103.587 mg active ingredient (a.i.)/L. The resistance of C. suppressalis to chlorantraniliprole is increasingly serious in most of the regions in Hunan. The levels of resistance of C. suppressalis to chlorantraniliprole ranged from 11.1-fold to 74.4-fold compared with a susceptible population, respectively. During the 8 years, the resistance level of C. suppressalis to chlorantraniliprole at five monitoring points showed a fluctuating upward trend. The resistance of C. suppressalis to chlorantraniliprole in Hengyang is highest in every year. These data are useful in future monitoring program for detecting any changes in resistance as a result of use of the insecticide.

Transcriptome analysis was used to explore the molecular regulation mechanisms of the responses of house fly, Musca domestica L. (Diptera: Muscidae), larvae to mixed solutions of Escherichia coli, Salmonella sp., Staphylococcus aureus, and Streptococcus sp. Sequencing yielded 50,701 genes that were compared with each database. A total of 34,666 (59.06%) transcripts was successfully annotated. In addition, 3,524 differentially expressed genes were screened from the low concentration dose group and the control group, 5,129 were screened from the high concentration dose group and control group, and 7,462 were screened from the high concentration dose group and low concentration dose group. Of those, 1,252, 2,369, and 3,159 differentially expressed genes were annotated in the Gene Ontology database and 306, 676, and 987 differentially expressed genes were annotated in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, respectively. The enrichment analysis of differential gene KEGG showed that the enrichment of insulin signaling pathway, HIF-1 signaling pathway, and chemokine signaling pathway in larvae induced by the high concentration dose of the bacterial mixture was more apparent than that induced by injection with the low concentration dose. Differential gene expression and function further reveal the metabolic pathway of defense response induced by bacteria, which can help in better understanding the related mechanism.