Mortality and inhibition ofHelicoverpa zea Egg parasitism rates byTrichogramma in relation to trichome/methyl ketone-mediated insect resistance ofLycopersicon hirsutum f. glabratum, accession PI 134417.

The glandular trichome/methyl ketone-mediated insect resistance of the wild tomato,Lycopersicon hirsutum f. glabratum C.H. Mull, accession PI 134417, toManduca sexta (L.) andLeptinotarsa decemlineata (Say) was shown to affect adverselyTrichogramma pretiosum Riley. AdultT. pretiosum were killed by direct contact with PI 134417 foliage and by exposure to its volatiles. This effect was greatly reduced or eliminated by removing the exudate of the glandular trichomes from the foliage. 2-Tridecanone, a principal consituent of the foliar glandular trichomes of PI 134417, was toxic to adultT. pretiosum at concentrations similar to those associated with PI 134417 foliage. Incubation of parasitizedHelicoverpa (=Heliothis) zea (Boddie) eggs on PI 134417 foliage or 2-tridecanone-treated filter paper significantly reduced the proportion of eggs producing adult parasitoids. Similarly, incubation of parasitizedH. zea eggs on filter paper treated with 2-undecanone, another constituent of the glandular trichomes of PI 134417, caused an increase in the percentage of host eggs containing dead parasitoid pupae.