Jasmonicacid–elicited volatiles in wheat mediate pink stem borer suppression and parasitoid attraction

Wheat ( Triticum aestivum L.) productivity in South Asia is increasingly constrained by the pink stem borer ( Sesamia inferens ), a lepidopteran pest responsible for severe yield losses. Conventional insecticide use often results in resistance and ecological risks, underscoring the need for environmentally sustainable alternatives. In this study, we evaluated the efficacy of four elicitors—jasmonic acid (JA), salicylic acid (SA), methyl salicylate (MeSA), and chitosan—in enhancing wheat resistance under field conditions across two consecutive winter seasons. Foliar application of JA (5 mM at 35 and 45 days after sowing) significantly reduced ‘dead heart’ and ‘white ear’ incidence by 31.7% and 27.9%, respectively, and increased grain yield by 28.9% compared with untreated controls. Gas chromatography–mass spectrometry revealed that JA application and borer infestation induced complex volatile blends, with hydrocarbons such as octadecane and eicosane strongly enhancing the foraging efficiency of the egg parasitoid Trichogramma chilonis in laboratory assays. These findings highlight the dual role of JA-elicited volatiles in directly suppressing pest damage and indirectly promoting biological control, offering a practical framework for integrating elicitor-based defense activation into wheat integrated pest management (IPM) strategies.