Role of methyl salicylate and spontaneous field margin vegetation on plant–arthropod interactions to enhance biological control

BACKGROUND: Herbivore-induced plant volatiles (HIPVs) play multiple roles in mediating plant-arthropod species interactions. Methyl salicylate (MeSA) is a well-known HIPV given its effectiveness in attracting parasitoids and predators and its use in biological control strategies. In addition, non-crop vegetation of field margins are important habitats that harbor natural enemies but may fail to increase biological control. Volatiles like MeSA could synergistically interact with field margin vegetation and increase biological control within crops. The present study examines through a field experiment the effects of MeSA (MeSA-exposed versus control plants) and in-field location (near vegetation margins versus field center) on plant-arthropod interactions to enhance biological control of Brassicaceae pests. RESULTS: MeSA-exposed cabbage plants tended to have different volatile compositions than control plants, showing a slight proportional increase in 3-pentanol and the absence of hexenal in MeSA-exposed samples. Herbivore abundance was slightly lower in MeSA-exposed compared to control plants, while in-field location did not influence the second trophic level. Natural enemy abundance and parasitism rates were significantly higher in the field margins than in the center, but the opposite pattern was registered for predation. No MeSA effects were detected on third trophic level species. CONCLUSION: MeSA altered plant volatile organic compound (VOC) emissions and had a slight effect on herbivores, while natural enemies responded solely to field-margin vegetation. Our study highlights the importance of conserving spontaneous vegetation to support parasitoids and underscore the need to study several functional groups and trophic levels for improving biological control. The use of VOCs, integrated with habitat management strategies, represents a complementary approach to enhance pest control. © 2026 Society of Chemical Industry.