ACYLGLUCOSES FROM WILD TOMATOES ALTER BEHAVIOR AND REDUCE GROWTH AND SURVIVAL OF HELICOVERPA-ZEA AND SPODOPTERA-EXIGUA (LEPIDOPTERA, NOCTUIDAE)

2,3,4-Tri-O-acylated glucoses (acylglucoses), exuded by the trichomes of the wild tomato species Lycopersicon pennellii (Corr.) D'Arcy, are feeding or oviposition deterrents, or both, for a wide range of insect pests of cultivated tomatoes. We conducted this investigation to asce rtain the effect of acylglucoses on Helicoverpa zea (Boddie) and Spodo ptera exigua (Hubner), major pests of cultivated tomatoes. Findings in dicated that the acyl glucoses reduce growth and development of larvae of both species. Exposure to the compounds, in artificial diet and ap plied with spray to cultivated tomato leaves, resulted in retarded gro wth rates, extended duration of the life cycle, and reduced survival. In behavioral bioassays, acylglucoses were observed to deter host sele ction and feeding by neonates and third instars of both insect species . S. exigua consistently exhibited greater sensitivity to the presence of the compounds than H. zea. A simulation of the cumulative effects of the compounds on population development of both species in a field of acylglucose-producing tomato plants projected a decrease in the num ber of generations per season and dramatic reductions in population si ze, relative to the control field of standard tomato varieties. Acylgl ucoses also were found to stimulate H. zea oviposition behavior, which may be attributed to activity of the fatty acid moieties of these mol ecules. The threshold level for response by moths to these compounds w as below 50 mug/cm2. These compounds affect H. zea and S. exigua growt h and survival at levels that reasonably might be attained in a breedi ng program to develop acylsugar-synthesizing tomato cultivars. Implica tions of these results for the deployment of acylsugar-producing plant s and assessment of their potential pest resistance are discussed.