Global agricultural production is significantly hampered by insect pests, and the demand for natural pragmatic pesticides with environmental concern remains unfulfilled. Ageratina adenophora (Spreng.) also known as Crofton weed, is an invasive perennial herbaceous plant that is known to possess multiple bioactive compounds. In our study, two isomers of ageraphorone metabolites i.e, 10 Hα-9-oxo-ageraphorone (10HA) and 10 Hβ-9-oxo-ageraphorone (10HB), were identified from Crofton weed, exhibiting potent antifeedant and larvicidal activities against Plutella xylostella. For antifeedant activity, the median effective concentration (EC50) values for 10HA and 10HB in the choice method were 2279 mg/L and 3233 mg/L, respectively, and for the no choice method, EC50 values were 1721 mg/L and 2394 mg/L, respectively. For larvicidal activity, lethal concentration (LC50) values for 10HA and 10HB were 2421 mg/L and 4109 mg/L at 48 h and 2101 mg/L and 3550 mg/L at 72 h. Furthermore, both in- vivo and in-vitro studies revealed that the isomers 10HA and 10HB exhibited potent detoxifying enzymes inhibition activity such as carboxylesterase and glutathione S-transferases. Molecular docking and MD simulation analysis provide insight into the possible interaction between isomers of ageraphorone metabolites and Carboxylic Ester Hydrolase protein (Gene: pxCCE016b) of P. xylostella, which led to a finding that CarEH protein plays a significant role in the detoxification of the two compounds in P. xylostella. Finally, our findings show that the primary enzymes undergoing inhibition by isomers of ageraphorone metabolites, causing toxicity in insects, are Carboxylesterase and glutathione S-transferase.

A precise evaluation of the risk of establishing insect pests is essential for national plant protection organizations. This accuracy is crucial in negotiating international trade agreements for forestry-related commodities, which have the potential to carry pests and lead to unintended introductions in the importing countries. In our study, we employed both mechanistic and correlative niche models to assess and map the global patterns of potential establishment for Aeolesthes sarta under current and future climates. This insect is a significant pest affecting tree species of the genus Populus, Salix, Acer, Malus, Juglans, and other hardwood trees. Notably, it is also categorized as a quarantine pest in countries where it is not currently present. The mechanistic model, CLIMEX, was calibrated using species-specific physiological tolerance thresholds, providing a detailed understanding of the environmental factors influencing the species. In contrast, the correlative model, maximum entropy (MaxEnt), utilized species occurrences and spatial climatic data, offering insights into the species\' distribution based on observed data and environmental conditions. The projected potential distribution from CLIMEX and MaxEnt models aligns well with the currently known distribution of A. sarta. CLIMEX predicts a broader global distribution than MaxEnt, indicating that most central and southern hemispheres are suitable for its distribution, excluding the extreme northern hemisphere, central African countries, and the northern part of Australia. Both models accurately predict the known distribution of A. sarta in the Asian continent, and their projections suggest a slight overall increase in the global distribution range of A. sarta with future changes in climate temperature, majorly concentrating in the central and northern hemispheres. Furthermore, the models anticipate suitable conditions in Europe and North America, where A. sarta currently does not occur but where its preferred host species, Populus alba, is present. The main environmental variables associated with the distribution of A. sarta at a global level were the average annual temperature and precipitation rate. The predictive models developed in this study offer insights into the global risk of A. sarta establishment and can be valuable for monitoring potential pest introductions in different countries. Additionally, policymakers and trade negotiators can utilize these models to make science-based decisions regarding pest management and international trade agreements.

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.

The cotton boll weevil (CBW, Anthonomus grandis) stands as one of the most significant threats to cotton crops (Gossypium hirsutum). Despite substantial efforts, the development of a commercially viable transgenic cotton event for effective open-field control of CBW has remained elusive. This study describes a detailed characterization of the insecticidal toxins Cry23Aa and Cry37Aa against CBW. Our findings reveal that CBW larvae fed on artificial diets supplemented exclusively with Cry23Aa decreased larval survival by roughly by 69%, while supplementation with Cry37Aa alone displayed no statistical difference compared to the control. However, the combined provision of both toxins in the artificial diet led to mortality rates approaching 100% among CBW larvae (LC50 equal to 0.26 PPM). Additionally, we engineered transgenic cotton plants by introducing cry23Aa and cry37Aa genes under control of the flower bud-specific pGhFS4 and pGhFS1 promoters, respectively. Seven transgenic cotton events expressing high levels of Cry23Aa and Cry37Aa toxins in flower buds were selected for greenhouse bioassays, and the mortality rate of CBW larvae feeding on their T0 and T1 generations ranged from 75% to 100%. Our in silico analyses unveiled that Cry23Aa displays all the hallmark characteristics of β-pore-forming toxins (β-PFTs) that bind to sugar moieties in glycoproteins. Intriguingly, we also discovered a distinctive zinc-binding site within Cry23Aa, which appears to be involved in protein-protein interactions. Finally, we discuss the major structural features of Cry23Aa that likely play a role in the toxin\'s mechanism of action. In view of the low LC50 for CBW larvae and the significant accumulation of these toxins in the flower buds of both T0 and T1 plants, we anticipate that through successive generations of these transgenic lines, cotton plants engineered to overexpress cry23Aa and cry37Aa hold promise for effectively managing CBW infestations in cotton crops.

Insect pests rank among the major limiting factors in agricultural production worldwide. In addition to direct effect on crops, some phytophagous insects are efficient vectors for plant disease transmission. Large amounts of conventional insecticides are required to secure food production worldwide, with a high impact on the economy and environment, particularly when beneficial insects are also affected by chemicals that frequently lack the desired specificity. RNA interference (RNAi) is a natural mechanism gene expression regulation and protection against exogenous and endogenous genetic elements present in most eukaryotes, including insects. Molecules of double-stranded RNA (dsRNA) or highly structured RNA are the substrates of cellular enzymes to produce several types of small RNAs (sRNAs), which play a crucial role in targeting sequences for transcriptional or post-transcriptional gene silencing. The relatively simple rules that underlie RNAi regulation, mainly based in Watson-Crick complementarity, have facilitated biotechnological applications based on these cellular mechanisms. This includes the promise of using engineered dsRNA molecules, either endogenously produced in crop plants or exogenously synthesized and applied onto crops, as a new generation of highly specific, sustainable, and environmentally friendly insecticides. Fueled on this expectation, this article reviews current knowledge about the RNAi pathways in insects, and some other applied questions such as production and delivery of recombinant RNA, which are critical to establish RNAi as a reliable technology for insect control in crop plants.

The soybean bud borer, a soybean pest in Brazil, was initially identified as Crocidosema aporema (Walsingham 1914) (Lepidoptera: Tortricidae). Outbreaks of this species have recently increased, but identification of this pest remains uncertain, and the historical factors associated with its geographic distribution in Brazil are little known. Here, we conducted a species characterization and phylogeographic analysis based on molecular and morphological evidence. Ninety individuals of bud-borers Lepidoptera were collected in different regions of Brazil. We sequenced COI and COII mitochondrial genes and examined wing patterns and male genital morphology. DNA barcoding approach revealed that 10 individuals were Argyrotaenia sphaleropa (Meyrick 1909) (Lepidoptera: Tortricidae) and 80 were a species of the genus Crocidosema Zeller. The morphology of the adult genitalia and wings proved to be insufficient to confirm the identification of Brazilian individuals as C. aporema, a species originally described from a high-elevation site in Costa Rica. Furthermore, the genetic distance between putative C. aporema specimens from Brazil and Costa Rica (ranging from 5.2% to 6.4%) supports the hypothesis that the Brazilian specimens are not referable to C. aporema. Our analysis revealed a single genetic strain (i.e., species) with low genetic diversity on soybean crops. We found no indication that the genetic structure was related to geographic distance among populations or edaphoclimatic regions. The population expansion of the soybean bud borer coincides with the increase in the area of soybean production in Brazil, suggesting that expanded soybean farming has allowed a significant increase in the effective population size of this pest.

BACKGROUND: Crop pests seriously affect the yield and quality of crops. Accurately and rapidly detecting and segmenting insect pests in crop leaves is a premise for effectively controlling insect pests.
METHODS: Aiming at the detection problem of irregular multi-scale insect pests in the field, a dilated multi-scale attention U-Net (DMSAU-Net) model is constructed for crop insect pest detection. In its encoder, dilated Inception is designed to replace the convolution layer in U-Net to extract the multi-scale features of insect pest images. An attention module is added to its decoder to focus on the edge of the insect pest image.
RESULTS: The experiments on the crop insect pest image IP102 dataset are implemented, and achieved the detection accuracy of 92.16% and IoU of 91.2%, which is 3.3% and 1.5% higher than that of MSR-RCNN, respectively.
CONCLUSIONS: The results indicate that the proposed method is effective as a new insect pest detection method. The dilated Inception can improve the accuracy of the model, and the attention module can reduce the noise generated by upsampling and accelerate model convergence. It can be concluded that the proposed method can be applied to practical crop insect pest monitoring system.

The onion aphid, Neotoxoptera formosana, poses a significant threat to Allium crops worldwide, causing considerable economic losses and quality degradation. To develop effective pest management strategies, it is crucial to understand the feeding behavior and life history of this pest on different Allium crops. In this study, the electrical penetration graph (EPG) technique was used to monitor the thorn-feeding behavior of the onion aphid on 4 Allium crops: leek, chive, garlic, and shallot. The EPG data revealed distinct feeding patterns, with garlic and shallots being more preferred hosts than chives. Additionally, the aphids primarily fed on the phloem in garlic and shallots. Analysis of life history trait showed that chives provided the most favorable conditions for aphid development and reproduction, while leek exhibited relatively unfavorable conditions. Examination of leaf histology also revealed differences among the crops, which may influence aphid feeding behavior. This study provides valuable insights into the interaction between the onion aphid and different Allium crops, aiding in the development of comprehensive pest control strategies to minimize crop damage and economic losses. The use of advanced techniques like EPG contributes to a more detailed understanding of aphid behavior and shows promise for improving pest management in other plant-pest interactions.

Aphid genomic resources enable the study of complex life history traits and provide information on vector biology, host adaption and speciation. The currant-lettuce aphid (Nasonovia ribisnigri (Hemiptera: Aphididae) (Mosley)) is a cosmopolitan pest of outdoor lettuce (Lactuca sativa (Asterales: Asteraceae) (Linnaeus)). Until recently, the use of resistant cultivars was an effective method for managing N. ribisnigri. A resistant cultivar containing a single gene (Nr-locus), introduced in the 1980s, conferred complete resistance to feeding. Overreliance of this Nr-locus in lettuce resulted in N. ribisnigri\'s ability to break resistance mechanism, with first reports during 2003. Our work attempts to understand which candidate gene(s) are associated with this resistance-breaking mechanism. We present two de novo draft assembles for N. ribisnigri genomes, corresponding to both avirulent (Nr-locus susceptible) and virulent (Nr-locus resistant) biotypes. Changes in gene expression of the two N. ribisnigri biotypes were investigated using transcriptomic analyses of RNA-sequencing (RNA-seq) data to understand the potential mechanisms of resistance to the Nr-locus in lettuce. The draft genome assemblies were 94.2% and 91.4% complete for the avirulent and virulent biotypes, respectively. Out of the 18,872 differentially expressed genes, a single gene/locus was identified in N. ribisnigri that was shared between two resistant-breaking biotypes. This locus was further explored and validated in Real-Time Quantitative Reverse Transcription PCR (qRT-PCR) experiments and has predicted localisations in both the cytoplasm and nucleus. This is the first study to provide evidence that a single gene/locus is likely responsible for the ability of N. ribisnigri to overcome the Nr-locus resistance in the lettuce host.

The West Indian fruit fly, Anastrepha obliqua, is a major pest of mango in Central and South America and attacks more than 60 species of host fruits. To support current genetic and genomic research on A. obliqua, we sequenced the genome using high-fidelity long-read sequencing. This resulted in a highly contiguous contig assembly with 90% of the genome in 10 contigs. The contig assembly was placed in a chromosomal context using synteny with a closely related species, Anastrepha ludens, as both are members of the Anastrepha fraterculus group. The resulting assembly represents the five autosomes and the X chromosome which represents 95.9% of the genome, and 199 unplaced contigs representing the remaining 4.1%. Orthology analysis across the structural annotation sets of high quality tephritid genomes demonstrates the gene annotations are robust, and identified genes unique to Anastrepha species that may help define their pestiferous nature that can be used as a starting point for comparative genomics. This genome assembly represents the first of this species and will serve as a foundation for future genetic and genomic research in support of its management as an agricultural pest.