Whitefly-Induced Tomato Volatiles Mediate Host Habitat Location Of The Parasitic Waspencarsia Formosa, And Enhance Its Efficacy As A Bio-Control Agent

BACKGROUND WhiteflyBemisia tabaciis a phloem-feeding insect and causes extensive agricultural damage around the world. Although the parasitic waspEncarsia formosais widely used to controlB. tabacion glasshouse tomatoes, low efficiency and discontinuity are frequently recorded. It has been well-documented that herbivore-induced plant volatiles (HIPVs) are important cues in the foraging behavior of the natural enemies of herbivores. However, the volatiles emitted from tomatoes infested by different developmental stages ofB. tabaci(nymphsversusadults) have not been compared in terms of their effects onE. formosaattraction. RESULTS Olfactometer assays with four tomato cultivars revealed that theE. formosawasps showed a significant attraction to the volatiles from adult-infested plants (except for cv. Castlemart), but not to those from nymph-infested plants. In a close-range habitat, however, the wasps appeared to use visual or tactile cues derived from nymphs for host location. Volatile analyses and behavioral assays showed that wasp attraction was correlated with enhanced beta-myrcene and beta-caryophyllene emissions from adult-infested plants. Furthermore, the use ofB. tabaciadult-induced plant cues under glasshouse conditions resulted in a higher parasitism rate by this parasitoid. CONCLUSION Our findings confirm thatE. formosauses the HIPVs resulting from feeding ofB. tabaciadults to locate host habitat. Release of beta-myrcene and beta-caryophyllene from dispensers may enhance the efficacy ofE. formosaas a biological control agent againstB. tabaciin glasshouse production systems.