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BACKGROUND: Piriformospora indica is an endophytic fungus that can promote the growth and confer resistance against diverse stresses in host plants by root colonization. However, the effects of P. indica colonization on improving plant resistance to insect pests are still less explored. The brown planthopper (BPH) Nilaparvata lugens is a serious monophagous pest that causes extensive damage to rice plants. Here, we aimed to evaluate the effects of P. indica colonization on rice resistance against BPH. RESULTS: The colonization of P. indica in rice roots resisted damage from BPH. Age‐stage, two‐sex life table analyses showed that feeding on P. indica‐colonized rice plants affected BPH's female adult longevity, oviposition period, fecundity, population parameters and population size. BPH female adults feeding on P. indica‐colonized plants excreted less honeydew. P. indica colonization remarkably increased the duration of np, N2, and N3 waveform, as well as the occurrences of N1 and N2, and decreased the duration of N4‐b for BPH on rice plants. Meanwhile, the weight of BPH on the colonized plants was significantly lower than the control. In addition, the feeding and oviposition preferences of BPH to P. indica‐colonized plants were reduced. qRT‐RCR analyses revealed that P. indica colonization induced the expressions of jasmonic acid (JA)‐ and salicylic acid (SA)‐related genes in rice plants. CONCLUSION: P. indica colonization can reduce BPH performance on rice plants with potential inhibitory effects on population growth. Collectively, these results support the potential for endophytically colonized P. indica as an effective strategy to improve insect resistance of crops. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Insects use odor detection to sense their surroundings. Use of volatile compounds, such as essential oils (EOs) of plants, to repel pests and disrupt their olfaction‐driven behaviors has great practical potential for use in integrated pest management. Despite the available information on the repellent effects of EOs on herbivorous insects, the olfaction‐based mechanisms remain unknown. RESULTS: Y‐tube olfactometer tests showed that the EOs of three Lamiaceae plants – Mentha arvensis L., Mentha piperita L. and Lavandula angustifolia Mill. – were significantly repellent to winged cotton aphid, Aphis gossypii Glover. Electrical penetration graph (EPG) tests indicated the EOs reduced phloem feeding and increased the level of non‐productive probing by the aphids. The EOs also reduced the fecundity of winged Aphis gossypii. Electrophysiological bioassays and gas chromatography–mass spectrometry (GC–MS) identified five physiologically active volatiles, that is menthone, isomenthone, neomenthol and menthol from Mentha piperita; menthone and menthol from Mentha arvensis; and linalool from L. angustifolia. Behavioral tests confirmed that all five compounds repelled winged Aphis gossypii. Under field conditions, the growth rate of aphid populations after 7 days was significantly lower in fields treated with these compounds than in the control fields. CONCLUSION: Our findings demonstrated that three EOs not only repelled winged Aphis gossypii but also interfered with the aphid's feeding behavior and reduced its fecundity. These EOs and their active constituents have great potential as eco‐friendly control products for use against Aphis gossypii. The effects of these EOs also exceed other repellents that only keep pests away from host plants. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Rice stripe virus (RSV) is one of the most serious rice diseases in East Asia. The small brown planthopper (SBPH), Laodelphax striatellus, is an economically important rice pest. SBPH transmits RSV horizontally and vertically, resulting in serious rice economic losses. Exposure to sublethal doses of insecticides can induce many physiological and cellular changes in insects. However, the mechanism underlying triazophos‐induced RSV vertical transmission remains unclear. Here, we investigated the role of vitellogenin (Vg) in triazophos‐induced RSV vertical transmission. RESULTS: RSV vertical transmission rates were significantly induced by sublethal exposure to triazophos. The transcript abundance of viral RNA3 segment (RNA3) and capsid protein (CP) in the ovaries of SBPH were also significantly increased. Triazophos induced the expression level of Vg in L. striatellus (LsVg) and increased the contents of ovarian protein and fat body protein. Knockdown of Vg significantly reduced the expression levels of LsVg and Vg receptor (LsVgR), and decreased RSV accumulations in the ovaries. Double‐stranded Vg (dsVg)‐mediated down‐regulation could be rescued by exposure to triazophos. Vertical transmission rate of the dsVg‐injected group was significantly decreased compared with the dsGFP‐injected group, and triazophos significantly rescued the RSV vertical transmission rate of the dsVg‐injected group. CONCLUSION: Our results indicate that triazophos‐induced RSV vertical transmission is associated with Vg. This work will help us to further elucidate sublethal doses of insecticides‐mediated effects and develop new strategies for pest control. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]