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Megalurothrips usitatus, is an important pest of cowpeas Vigna unguiculata, that causes severe damage to cowpea crops in Southeast Asia and Hainan Province in China. Neoseiulus newsami is a natural enemy of M. usitatus that was first reported from Ledong Li Autonomous County, Hainan, China. Here, we evaluated the potential of N. newsami as a biocontrol agent for use against M. usitatus. In laboratory tests, N. newsami showed a similar rate of attack on this pest as did the better-known species Neoseiulus barkeri. The functional response curve of N. newsami fed M. usitatus showed that more 1st instar prey were consumed by N. newsami at higher prey densities, indicating a Type III functional. The maximum attack coefficient (a) was 0.063 ± 0.011 and the handling time per consumed prey (Th) was 0.58 ± 0.09. The maximum attack rate (T/Th) was 41.37. Neoseiulus newsami showed higher predation and oviposition rates than did N. barkeri or Neoseiulus cucumeris. Our results suggest that N. newsami has a higher predation capacity against M. usitatus. [ABSTRACT FROM AUTHOR]

BACKGROUND: Entomophagous fungi (EPF) not only directly kill insect pests, but also colonize plants and improve their resistance against pests. However, most previous research has focused on Beauveria bassiana and Metarhizium anisopliae, and there are few reports on whether other EPF can enhance resistance against pests via endogenous colonization. Herein, an EPF strain was isolated from diseased larvae of Spodoptera litura in a soybean field, and subjected to genome‐wide sequencing at the chromosomal level. The pathogenicity of the isolate toward various pest insects was evaluated, and the ability to colonize plants and induce resistance against phytopathogens and insect pests was tested. RESULTS: The purified isolate was identified as M. rileyi and designated MrS1Gz1–1. Biological assays revealed its strong pathogenicity toward five insect pests belonging to Lepidoptera and Hemiptera. Furthermore, the strain inhibited the growth of soil‐borne plant disease caused by Sclerotinia sclerotiorum in vitro. It colonized plants as an endophyte via soil application, thereby inducing plant resistance‐related genes against phytopathogen infection, and it disrupted the feeding selectivity of S. litura larvae. CONCLUSION: M. rileyi MrS1Gz1–1 has potential as a broad‐spectrum microbial control agent that can induce resistance against phytopathogens and insect pests feeding as an endotype. The complete genome provides a valuable resource for exploring host interactions. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In citrus cultivation, it is a difficult task for farmers to classify different pests correctly and make proper decisions to prevent citrus damage. This work proposes an efficient modified lightweight transfer learning model which combines the effectiveness and accuracy of citrus pest characterization with mobile terminal counting. Firstly, we utilized typical transfer learning feature extraction networks such as ResNet50, InceptionV3, VGG16, and MobileNetV3, and pre-trained the single-shot multibox detector (SSD) network to compare and analyze the classification accuracy and efficiency of each model. Then, to further reduce the amount of calculations needed, we miniaturized the prediction convolution kernel at the end of the model and added a residual block of a 1 × 1 convolution kernel to predict category scores and frame offsets. Finally, we transplanted the preferred lightweight SSD model into the mobile terminals developed by us to verify its usability. Compared to other transfer learning models, the modified MobileNetV3+RPBM can enable the SSD network to achieve accurate detection of Panonychus Citri Mcgregor and Aphids, with a mean average precision (mAP) up to 86.10% and the counting accuracy reaching 91.0% and 89.0%, respectively. In terms of speed, the mean latency of MobileNetV3+RPBM is as low as 185 ms. It was concluded that this novel and efficient modified MobileNetV3+RPBM+SSD model is effective at classifying citrus pests, and can be integrated into devices that are embedded for mobile rapid detection as well as for counting pests in citrus orchards. The work presented herein can help encourage farm managers to judge the degree of pest damage and make correct decisions regarding pesticide application in orchard management. [ABSTRACT FROM AUTHOR]

(E)-β-ocimene, a ubiquitous monoterpene volatile in plants, is emitted from flowers to attract pollinators and/or from vegetative tissues as part of inducible defenses mediated by complex signaling networks when plants are attacked by insect herbivores. Wild pear species Pyrus betuleafolia used worldwide as rootstock generally displays valuable pest-resistant traits and is a promising genetic resource for pear breeding. In the current study, transcriptional changes in this wild pear species infested with a polyphagous herbivore Spodoptera litura and the underlying molecular mechanisms were fully investigated. A total of 3,118 differentially expressed genes (DEGs) were identified in damaged pear leaf samples. Spodoptera litura larvae infestation activated complex phytohormonal signaling networks in which jasmonic acid, ethylene, brassinosteroids, cytokinin, gibberellic acid and auxin pathways were induced, whereas salicylic acid and abscisic acid pathways were suppressed. All DEGs associated with growth-related photosynthesis were significantly downregulated, whereas most DEGs involved in defense-related early signaling events, transcription factors, green leaf volatiles and volatile terpenes were significantly upregulated. The PbeOCS (GWHGAAYT028729), a putative (E)-β-ocimene synthase gene, was newly identified in P. betuleafolia transcriptome. The upregulation of PbeOCS in S. litura-infested pear leaves supports a potential role for PbeOCS in herbivore-induced plant defenses. In enzyme-catalyzed reaction, recombinant PbeOCS utilized only geranyl pyrophosphate but not neryl diphosphate, farnesyl pyrophosphate or geranylgeranyl diphosphate as a substrate, producing (E)-β-ocimene as the major product and a trace amount of (Z)-β-ocimene. Moreover, as a catalytic product of PbeOCS, (E)-β-ocimene showed repellent effects on larvae of S. litura in dual-choice bioassays. What is more, (E)-β-ocimene increased mortalities of larvae in no-choice bioassays. These findings provide an overview of transcriptomic changes in wild pears in response to chewing herbivores and insights into (E)-β-ocimene biosynthesis in pear plants, which will help elucidate the molecular mechanisms underlying pearinsect interactions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is an important natural enemy of aphids. Plant species and plant health conditions can affect the behavior of H. axyridis. To determine plant effects on this lady beetle, we examined beetle responses to four cover crops: coriander (Coriadrum sativum L., Apiales: Apiaceae), marigold (Tagetes erecta L., Asterales: Asteraceae), sweet alyssum (Lobularia maritima L., Brassicales: Brassicaceae), and alfalfa (Medicago sativa L., Fabales: Fabaceae). Our goal was to better understand this predator's ovipositional behavior in response to different plants and its olfactory response to the aphid‐induced volatiles from these plants. RESULTS: We found that this lady beetle did not have any significant oviposition preference among the four plant species, but H. axyridis preferred to lay eggs on the lower surface of leaves, regardless of the plant species. H. axyridis females had a significant preference for aphid‐infested marigolds, but were not attracted by any of the other three cover plants or marigolds without aphid damage. Compared to the uninfested marigold plants, the emission of 12 compounds significantly increased on the aphid‐infested marigolds, and two of them were attractive to H. axyridis under suitable concentrations. CONCLUSION: H. axyridis did not show any significant oviposition preference among the four cover crops. Aphid‐infested marigolds can attract H. axyridis. Indole and terpinen‐4‐ol mediated lady beetle attraction. These synomones have potential for manipulating populations of H. axyridis as a component of conservation biological control. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]