Interaction ofManduca sexta resistance in tomato with insect predators ofHelicoverpa zea

Resistance in accession PI 134417 ofLycopersicon hirsutum f.glabratum toManduca sexta L. results from the presence of the methyl ketones 2-tridecanone and 2-undecanone in the type VI trichome glands on foliage of these plants. Short (24 h) and long term (neonate to adult) laboratory experiments usingM. sexta-resistant and susceptible foliage and methyl ketone treated filter paper disks were conducted to evaluate the direct (plant-mediated), and indirect (prey-mediated) effects of this resistance on two predators ofHelicoverpa zea eggs,Coleomegilla maculata (DeGeer) andGeocoris punctipes (Say). Direct effects of resistance were manifest as reduced egg consumption and increased mortality for both predators. Indirect effects were manifest as reduced egg consumption byG. punctipes, but were not observed forC. maculata. Results of experiments using methyl ketone-treated filter paper disks instead of foliage were similar.