Prohydrojasmon treatment of Brassica juncea alters the performance and behavioural responses of the cabbage aphid, Brevicoryne brassicae

Plants encounter a myriad of biotic and abiotic stresses throughout their life cycle, among which aphids pose a significant challenge as herbivorous insect pests. Aphids cause both direct damage through feeding and indirect damage by transmitting viruses. Given the growing concerns about insecticide resistance and the non-target effects of synthetic insecticides, there is an urgent need to develop novel pest control strategies that are dependent on plant defence strategies. In this study, we assessed the effects of exogenous prohydrojasmon (PDJ), a derivative of jasmonic acid, at 24 h (PDJ₂₄) and 48 h (PDJ₄₈) post-treatment on the cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae), feeding on Brassica juncea L. (Brassicaceae). The impact of PDJ treatments was assessed by conducting performance bioassays (survival and fecundity) and behavioural bioassays (settlement and attraction to volatiles in an olfactometer). Our findings reveal that the exogenous application of PDJ did not significantly affect on the performance and behaviour of B. brassicae at 24-h post-treatment. However, PDJ treatment significantly reduced the performance of B. brassicae at 48-h post-treatment, and affected the behaviour in terms of reduced settlement on and attraction to volatiles of PDJ-treated plants. These results suggest that PDJ has the potential to effectively induce defences in Brassica against sucking pests. This study provides valuable insights into possibility of employing PDJ as an alternative approach for sustainable pest management in agriculture.