Quantitative real-time PCR (qRT-PCR) is a widely applied technique for accurately assessing the expression of target genes. In practice, the evaluation of gene expression requires appropriate reference genes. To screen reliable reference genes for evaluating gene expression via qRT-PCR in Mythimna loreyi, a notorious migratory pest across Asia, Africa, Europe, and Australia, we assessed the expression stability of 13 candidate reference genes in M. loreyi using the ΔCt method, BestKeeper, Normfinder, GeNorm, and the web-based comprehensive platform RefFinder. These reference genes include RPL10, RPL27, RPL32, RPS3, TATA−box, GAPDH, AK, Actin, EF, α−tubulin, SOD, 18S rRNA, and FTZ−F1, which is frequently employed in Lepidoptera insects. Our findings revealed that the performance of the candidate reference gene depended on experimental conditions. Specifically, RPL27 and RPL10 were the most suitable for evaluating expression changes across developmental stages, tissues, and adult ages. The optimal reference genes were recommended in specific experiment conditions, for instance, EF and RPS3 were recommended for mating status, AK and RPL10 were recommended for temperature treatments, RPL27 and FTZ−F1 were recommended for larva diet, and EF and RPL27 were recommended for adult diet treatments. Additionally, expression profiles of pheromone-binding protein 2 (MlorPBP2) and glutathione S-transferase (MlorGST1) were used to validate the reference genes. This study provides reference genes for the accurate normalization of qRT-PCR data, laying the groundwork for studying the expression of target genes in M. loreyi.

Ecdysone receptor (EcR) and chitinase play a critical role in the molting stage of insect pests. Each of them is considered a promising target for the development of novel insect growth regulators (IGRs). In the present paper, a total of 24 (23 novel) hexacyclic pyrazolamide derivatives were designed and synthesized by reducing the heptacycle and inserting small flexible linkers on the basis of the previously discovered dual-target compound D-27 acting simultaneously on EcR and Ostrinia furnacalis chitinase (OfChtI). Their insecticidal activities against Plutella xylostella, Spodoptera frugiperda, and Ostrinia furnacalis larvae were evaluated. The results revealed that the insecticidal activity was not significantly enhanced when the heptacycle on the pyrazole ring was reduced to a hexacycle. However, the insertion of an additional methylene spacer between the substituted phenyl ring and the amide bond can improve the insecticidal activity. Among the derivatives, the most potent compound, 6j, exhibited promising insecticidal activities against P. xylostella and S. frugiperda. Further protein binding assays and molecular docking indicated that 6j could target both EcR and OfChtI, and is a potential lead compound for IGRs. The present work provides valuable clues for the development of new dual-target IGRs.

Quantitative real-time PCR (qRT-PCR) is widely accepted as a precise and convenient method for quantitatively analyzing the expression of functional genes. The data normalization strongly depends upon stable reference genes. The bean bug, Riptortus pedestris (Hemiptera: Alydidae), is a significant pest of leguminous crops and broadly distributed across Southeast Asia. In this study, a total of 16 candidate reference genes (RPL32, RPS23, SDHA, UBQ, UCCR, GST, TATA−box, HSP70, GAPDH, RPL7A, SOD, RPS3, Actin, α−tubulin, AK, and EF1) were carefully chosen in R. pedestris, and their expression levels were assessed across various conditions, including different developmental stages, diverse tissues, temperature treatments, adult age, molting time, and mating status. Following this, the stability of these reference genes was evaluated using four algorithms (ΔCt, GeNorm, NormFinder, and BestKeeper). Ultimately, the comprehensive rankings were determined using the online tool RefFinder. Our results demonstrate that the reference gene for qRT-PCR analysis in R. pedestris is contingent upon the specific experimental conditions. RPL7A and EF1 are optimal reference genes for developmental stages. Furthermore, α−tubulin and EF1 exhibit the most stable expression across various adult tissues. RPL32 and RPL7A exhibit the most stable expression for adult age. For nymph age, RPL32 and SOD display the most stable expression. For temperature conditions, RPS23 and RPL7A were identified as the most suitable for monitoring gene expression. Lastly, we verified the practicability of evaluating expression levels of odorant-binding protein 37 (RpedOBP37) and cytochrome P450 6a2 (RpedCYP6) throughout developmental stages, tissues, and temperature conditions. These findings are a significant addition to the qRT-PCR analysis studies on R. pedestris, serving as a fundamental groundwork for future investigations on stable reference genes in R. pedestris as well as other organisms.

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a major pest in cotton production, notorious for its rapid development of resistance to pesticides, which complicates control efforts. A sustainable solution involves combining selective insecticides with biocontrol agents to reduce pest populations while preserving natural enemies. Afidopyropen, a novel transient receptor potential vanilloid-targeted insecticide, was extremely safe for the minute pirate bug Orius sauteri Poppius (Hemiptera: Anthocoridae), a common predator of small pests. The LC50 values for direct exposure were 592.38, 497.02, and 382.71 mg/L for the fifth instars and female and male adults, respectively. Even at the maximum recommended field rate, afidopyropen had minimal impact on the survival, predation efficiency, and reproduction of pesticide-treated O. sauteri and their offspring. Despite the resistance observed in field-collected A. gossypii, combining a low concentration of afidopyropen with O. sauteri significantly reduced aphid populations. By day 7 post-treatment, aphid density was decreased by over 94.29%. While a higher concentration of afidopyropen initially achieved 98.19% control, aphid populations rebounded over time. This study demonstrated that afidopyropen was extremely safe for O. sauteri as indicated by the higher LC50 values. The combination of a low concentration of afidopyropen with O. sauteri offers an effective control approach for resistant A. gossypii, presenting a novel integrated pest management strategy.

Insect sex pheromones have been widely used in integrated pest control due to their efficiency, non-toxicity, specificity, and environmental sustainability. They are considered a key component of green pest management techniques. Polymerus pekinensis is a phytophagous plant bug on alfalfa (Medicago sativa L.) in East Asia. This study used gas chromatography–electroantennogram detection (GC–EAD) and gas chromatography–mass spectrometry (GC–MS) to analyze the whole-body extracts from male and female P. pekinensis. Octyl acetate (OA) and decyl acetate (DA) elicited the antennal response of males and were identified as the predominant components of female and male extracts, respectively. Subsequent field trials demonstrated that OA (>8 mg per lure) showed the strongest attraction to conspecific males. However, when DA was added in a lure (≥2 mg), a significant decline in captures occurred. These findings provide new insights into the understanding of sex pheromones in Miridae and benefit the development of sustainable management of P. pekinensis.