Effects Of Different Host Plants On Growth, Development And Feeding Behaviors Of Bemisia Tabaci B Biotype

Bemisia tabaci is one of the most important crop pests in the world. It has developed into many biotypes such as A, B, Q, J, and so on. Compared to other biotypes, B biotype distributes more widely and damages more seriously the crop yield, so controlling it is more difficult. It is of theorectical and practical significance to study this pest's damaging causes, including the relationship between host plants and insects, for laying basis for effective management measures. In this study, effects of different host plants on growth, development and feeding behaviors of Bemisia tabaci B biotype were studied in the hope that eluciating the resistance mechanism of hostplants to Bemisia tabaci B biotype in order to provide some evidences for effective pest controlling strategies, such as resistant crop breeding, inter-cropping and so on.In the study, biological and morphological characteristics, as well as body sizes of Bemisia tabaci B biotype were compared on different host plants, feeding behaviors of Bemisia tabaci B biotype were recorded with direct current electrical penetration graph (DC-EPG), and the resistence mechanisms of different hostplants to the pest was analyzed. The results are shown as follows:(1) There were no significant differences in the morphological characteristics of B biotype whitefly on three hostplants,but some differences were found in the nymph sizes of same stages on three hostplants in the first and second nymph stage.(2) Under laboratory conditions,observations and experiments were conducted on sizes, developmental durations,survaval rates and life parameters of Bemisia tabaci biotype B on 4 host plants (cucumber,eggplants,and 2 tobacco varieties). The results showed that there were significant differences of parameters observed among insects on these 4 host plants. Cucumber is the most favorable host plant, followed by tobacco-K326, while eggplant was the least suitabble for development and reproduction of Bemisia tabaci biotype B.(3) Feeding behaviors of Bemisia tabaci B biotype on 4 kinds of hostplants were analyzed with DC-EPG. The results indicated that during probing,compared on other three hostplants, the Bemisia tabaci B biotype feeding on cumumber had much less prob time, the shortest in duration of E1 on phloem phase,and the the longest in duration of E2 on the phloem phase;On tobacco, Bemisia tabaci B biotype got less numbers of probes and the shorter duration of E2 on phloem phase;The Bemisia tabaci B biotype feeding on the squash got the shortest probing and duration of E2 on phloem phase. We can conclude from these results that the resistence factors of cumumber to Bemisia tabaci B biotype probably existed on the leaf surface or within mesophyll, while showed resistence factors from leaf surface to the phloem in tobacco and squash, and resistence factors in the whole feeding process in eggplants.