EFFECTS OF HOST-PLANT AND TEMPERATURE ON GROWTH AND REPRODUCTION OF THRIPS PALMI (THYSANOPTERA, THRIPIDAE)

Development time and life table parameters of Thrips pal mi Karny, a p est new to the continental United States, were measured at 3 temperatu res on 4 host plants. Net reproductive rate was the highest because of greatest survival and highest egg production when thrips were reared at 26 degrees C on winter melon, Benincasa hispida (Thunb.) Cogn., egg plant, Solanum melongena L., and cucumber, Cucumis sativus L., compare d with bell pepper. However, because of shorter development time, the intrinsic rates of natural increase for T. palmi were highest when ind ividuals were reared at 32 degrees C on these 3 host plants. Although development times were similar on all 4 hosts at 26 degrees C, surviva l and reproduction were much lower for thrips reared on bell pepper, C apsicum annuum L., leaves. At 15 and 32 degrees C, these differences w ere even greater, with only 40 and 48% of thrips reared on bell pepper surviving at the respective temperatures. T. palmi was able to tolera te the low temperature (56% mortality when held at 0 degrees C for 15 h) much better than the high temperature (100% mortality at 40 degrees C for 15 h), which may partially explain why T. palmi populations are high in winter and spring and low in the summer in Florida. This stud y provides information needed to understand population dynamics of thr ips in important vegetable crops, information which will be valuable i n developing and evaluating cultural and biological controls for this extremely damaging pest.