Journal of Pest Science最新文献

Human-induced changes, such as climate variability and escalating anthropogenic pressures, profoundly impact species distribution, dispersal, and competitive interactions worldwide. In the Neotropical region, the expansion of rice cultivation under these conditions has facilitated the spread of species within the rice stink bug complex, notably Oebalus species. Among these species, Oebalus pugnax prevails in the United States (US) and O. poecilus in Neotropical America co-occurring with O. ypsilongriseus, which was recently introduced into the US. This study explores the determinants and predictive variables influencing the occurrence and overlap of rice stink bugs, utilizing maximum entropy species distribution modeling to project their potential distribution. Precipitation and temperature were identified as pivotal factors shaping the ecological niche of O. pugnax in the US, while sensitivity to dry spells appears instrumental in the niche specialization of Neotropical species such as O. ypsilongriseus and O. poecilus. Notably, O. pugnax shows potential for establishment in South America, whereas O. ypsilongriseus and O. poecilus exhibit potential to establish in the southeastern US. Prospects that may aggravate concerns with their potential economic losses under the current trends on global climate changes. Although bioclimate-based distribution modeling provides valuable insights into habitat suitability and species distribution, future research should focus on delineating thermal and humidity thresholds for their development, as well as elucidating interspecific relationships. These endeavors are essential for enhancing our comprehension of their distribution dynamics and assisting in the design of effective pest management strategies, taking advantage of the biological peculiarities and susceptibility to different control methods by each individual species.

The fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is a highly polyphagous agricultural pest that seriously threatens food production and agricultural development. Lufenuron is widely used because of its good control effect and safety to nontarget organisms. However, due to the continuous application of lufenuron and the evolution of insect resistance mechanisms, the potential of S. frugiperda developing resistance to lufenuron is increasing. Insect gut bacteria play an important role in insecticide resistance. We established a germ-free (GF) rearing protocol and cultured monoassociated gnotobiotic S. frugiperda with 20 different bacteria to explore the possible mechanisms of gut bacteria resistance in insects. After the larvae were exposed to lufenuron, Klebsiella C3 was screened, which could significantly change the resistance of larvae to lufenuron. Moreover, chitin synthesis and metabolism in larvae fed with Klebsiella C3 were significantly affected. The liquid chromatography results showed that Klebsiella C3 could not directly degrade lufenuron. Nontargeted metabolomics analysis revealed that the intervention of Klebsiella C3 resulted in the production of different metabolites by S. frugiperda, which affected the associated metabolic pathways. These changes in substances may be responsible for the altered sensitivity of S. frugiperda to lufenuron. Taken together, our study investigated how intestinal bacteria influence the resistance of S. frugiperda against insecticides. This research offers new insights for developing preventive and control strategies against this key pest.

Insecticide resistance in pest control poses a threat to agricultural production and human health. Numerous insect species express genes coding for detoxification enzymes that have broad substrate promiscuity thus conferring resistance to various insecticides. However, whether the homologs of these genes play similar roles in resistance phenotypes of closely related species remains largely unclear. Therefore, this study compares the resistance profiles of three major rice planthopper species (Delphacidae) (Laodelphax striatellus, Nilaparvata lugens, and Sogatella furcifera) based on the metabolic activity of their cytochrome P450s. Genome-wide analyses resulted in 68, 70, and 64 P450 genes in L. striatellus, N. lugens, and S. furcifera, respectively. Phylogenetic analyses among these genes found that most resistance-related genes in one species had homologs in other planthopper species. The most resistance-relevant orthogroup (CYP6ERs) showed higher evolutionary instability than most other groups. RNAi and in vitro metabolism assays revealed that CYP6ERs confers more divergent insecticide resistance profiles among planthopper species than the other two major resistance-related P450 subfamilies (CYP6AYs and CYP4C61s). Alphafold-based structural predictions and alignments suggested that P450 orthogroups with higher phylogenetic instability tended to have less structural similarities, resulting in more divergent metabolic profiles. This relationship was also in silico validated on Aphidae aphids and Lepidoptera noctuids. This study proposes combined phylogenetic and toxicogenomic analyses for understanding CYPome-based insecticide resistance convergency and divergency among closely related pests. These findings may improve the accuracy and rationality of chemical pest control.

The fall armyworm, Spodoptera frugiperda, a significant pest, has spread to many countries in Africa and Asia in recent years, causing substantial losses in corn production. From 2019 to 2024, we monitored the host strain of S. frugiperda in various regions in Jiangsu Province, China. The result showed that only COIRS-TpiRS and COIRS-TpiCS strains were present in corn during 2019 and 2020. In 2021, COIRS-TpiRS, COIRS-TpiCS and COICS-TpiCS strains were detected in both corn and rice. By 2024, all the three strains were found exclusively in corn. Notably, the proportion of COIRS-TpiRS strain increased from 2019 to 2021, but declined in 2024. Experimental data demonstrated that COIRS-TpiRS had higher fitness on rice than on corn, and showed a preference for damaging and ovipositing on rice. However, the occurrence of S. frugiperda in rice paddies remains rare, suggesting that it is unlikely to become a significant threat to rice production in China in the coming years without change in rice planting pattern.

The deposition of atmospheric nitrogen has globally increased and has interfered with plant growth and resistance to herbivores. Previous studies have shown that numerous dioecious plant species exhibit sex-specific responses in growth and tolerance to increased atmospheric nitrogen deposition. However, whether these changes lead to sexual differences in herbivore resistance and subsequent intersexual competition between male and female conspecifics remains unknown. Here, we used female and male siblings of Populus deltoides to investigate the effect of simulated nitrogen deposition on herbivore resistance and competitive ability of male and female plant conspecifics under controlled and field conditions. We showed that simulated nitrogen deposition significantly increased the growth of both plant sexes, with females outperforming males. The herbivore feeding bioassays demonstrated that simulated nitrogen deposition decreased the resistance of both plant sexes to generalist and specialist herbivores, with female plants exhibiting lower resistance than males. This could be attributed to decreased levels of leaf structural defense in females in response to simulated nitrogen deposition. A short-term competition test in the climate chamber revealed that simulated nitrogen deposition increased the competitive ability of females over males, whereas herbivore feeding reversed this advantage. A long-term competition experiment in the field further confirmed that male plants may benefit from increased atmospheric nitrogen deposition through enhanced herbivore resistance and intersexual competition compared to their female conspecifics. The findings provide potential implications for the selection of suitable sex of dioecious plants during forestation in natural habitats experiencing high levels of atmospheric nitrogen deposition.

Nilaparvata lugens Stål is a significant insect pest of rice throughout Asia, and the use of insect-resistant rice varieties has been proposed as a key strategy to control this pest, and reduce reliance on insecticides. However, little is known about the interplay between these two methods, particularly their combined influence on the behavior, development, and reproduction. In this study, we found that both nitenpyram resistance in BPH and resistance in the rice variety to BPH jointly regulated wing dimorphism. A large proportion of long-winged BPHs (78%) were observed in the nitenpyram-resistant strain (NitR) when feeding on IR56, a BPH-resistant rice variety. No similar result in SUS (susceptible) insects was observed on either IR56 or TN1, nor in NitR insects on TN1. These results suggest that nitenpyram resistance and feeding on IR56 together regulated BPH wing dimorphism. Through quantitative analysis of hormone and insulin pathway genes, we found that a decrease in juvenile hormone (JH) and/or an increase in ecdysone (20E) induced the long-winged morph, accompanied by a reduction in the expression of insulin receptor 2 (InR2). Alterations in hormone levels and silencing InR2 could regulate wing morph differentiation. In males, JH III addition decreased long-wing proportion from 72 to 42%, while silencing InR2 increased long-wing proportion from 27 to 71%. This study suggests a potential risk that the insect-resistant rice variety may promote the spread of resistant insects, creating a contradiction in the combined use of insecticides and insect-resistant varieties.

Insecticides remain a primary tool in mosquito-borne disease control; however, the resistance in mosquito populations poses a significant challenge to the efficacy. Resistance mechanisms, including target sites mutations and increase in metabolic detoxification, have emerged due to wide spread insecticide use. The growing resistance to pyrethroids used in long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) necessitates alternative control strategies. Furthermore, synthetic insecticides often negatively impact the environment and nontarget organisms, highlighting the necessity of exploring alternative pest management strategies. Biological control methods utilizing natural predators, pathogens, and parasites of mosquitoes have shown promise as viable alternatives to traditional insecticide approaches.

The invasion of the fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), has posed a serious threat to maize production in Africa and Asia. Chemical insecticides and Bt maize are the main means for FAW control, but the interaction between these two measures is also unclear. In this study, the susceptibility of the field population (Ezhou) fed on Bt maize insecticidal protein and the Vip3Aa-resistant population DH-R (206-fold) to emamectin benzoate (EB) and chlorantraniliprole (CAP) was determined by the topical application method. The results showed that the susceptibility of both populations to the two insecticides increased significantly. The mechanism is attributed to the inhibition of the activities of enzymes detoxification enzymes, including carboxylesterase (CarE), glutathione S-transferase (GSTs), and multifunctional oxidase (MFO). The corrected control effects of Bt (Cry1Ab + Vip3Aa) maize combined with EB or CAP against larvae were measured by a spraying method in the laboratory and field. The results showed that the combined use of Bt (Cry1Ab + Vip3Aa) maize and EB increased the corrected control effect by 22.70%-22.86% in the laboratory and 16.74% in the field. Similarly, the combined use of Bt (Cry1Ab + Vip3Aa) maize and CAP increased the corrected control effect by 54.92%-61.59% in the laboratory and 19.62% in the field. It is concluded that the Bt (Cry1Ab + Vip3Aa) maize and chemical insecticides (EB and CAP) have synergistic effects against FAW, providing a theoretical basis for integrating Bt maize with chemical insecticides to manage the FAW populations.

The oriental fruit fly Bactrocera dorsalis is a highly destructive and invasive pest that threatens global horticulture, causing economic losses due to fruit damage and quarantine regulations. While attract-and-kill baits are widely used to suppress fly populations, these baits also impact many non-target species. To achieve ecological sustainability, our study aimed to develop a method that selectively targets female fruit flies. Using gas chromatography coupled to electro-antennal or palpal detection (GC-EAD/GC-EPD), we identified compounds that elicited responses in the maxillary palp and antenna of three different fruit flies including B. dorsalis, Ceratitis capitata, and Zeugodacus cucurbitae. As previous studies indicated the significance of compounds whose detection was shared among fruit fly species, we composed blends of such “shared compounds”. To test the hypothesis that compounds active on the palps and antennae are complementary and synergize attraction, we thus formulated three blends, a palpal, an antennal and a combined blend. Compounds were formulated in a wax emulsion for slow release and tested on B. dorsalis fruit flies in six choice and large room laboratory assays, as well as field trials. A blend of both antenna and maxillary palp-active compounds attracted more B. dorsalis than blends based on either antennae or palps alone, and exhibited a female-bias in captures. Furthermore, the blend was highly selective, capturing very few non-target organisms compared to torula yeast, a lure considered to be selective. Such lures are important in advancing targeted pest control strategies, ultimately contributing to more effective management of the devastating B. dorsalis population, and safeguarding global horticulture productivity.

Orius similis and Encarsia formosa are important natural enemies of Bemisia tabaci. However, there is limited understanding regarding the impact of O. similis on the control of B. tabaci by E. formosa when they are used in combination. Temperature changes will affect the food web, and Intraguild predation (IGP) is a fundamental component that constitutes a complex food web. Therefore, studying the effect of temperature on IGP is of great significance for understanding the mechanism of species interaction and improving the biocontrol ability of natural enemies. Our study investigated the interference of female adults of O. similis on unparasitized and parasitized B. tabaci nymphs (including 1-, 4-, 7-, and 10-day-old parasitoid immature nymphs) at different temperatures (19, 22, 25, 28, and 31 °C). The results showed that only the parasitism rate of E. formosa was lower than that of the treatment without O. similis on 1, 4, 7 and 10 days after being parasitized by E. formosa, indicating that O. similis preyed on E. formosa. In both the no-choice and choice experiments, O. similis showed a preference for feeding on B. tabaci nymphs that had been parasitized 1 and 4 days earlier, across various temperature conditions. When both unparasitized B. tabaci nymphs and parasitized 10-day-old B. tabaci nymphs were present, O. similis preferred to prey on unparasitized prey. Our results provide evidence that IGP interactions may be greatly affected by future increases in temperature. When the temperature increased from 19 to 28 °C, the IGP of O. similis was promoted with the increase in temperature. When the temperature exceeded 28 °C, IGP was inhibited. Therefore, in the combined application of these two natural enemies, the O. similis can be released again in the period or time period when the temperature is stable at 22–25 °C after 10 days of release of E. formosa to reduce the IGP intensity, so as to achieve better control effect and accelerate the establishment of an efficient biocontrol system of natural enemies of B. tabaci.