The Growth And Development Of Bemisia Tabaci And Amitus Sp. On Detached-leaf Of Host Plant

Bemisia tabaci (Gennadius) causes the great loss of agricultural production of the world. The control effect of pesticides is low because of their waxy surface and always living at the back of the leaves. Therefore, more and more attention has been paid to biological control, and as an important alternative, which becomes an important part of B.tabaci comprehensive management nowadays.In order to study the morphology and biology characteristics of the Amitus sp., one of the natural enemies of the B.tabaci in Fuzhou, we used the detached-leaf of host plants to rear B.tabaci, instead of the old feeding method. The major results were as follows:1) Based on the research of the developmental duration, body length and width, and the rate of hatchability and emergence of B.tabaci on the detached-leaf of cabbage, sweet potato, green beans and tobacco, it show that sweet potato and cabbage were the better host plants for rearing whitefly.2) There were differences in developmental duration, body length and width on the detached-leaf keeping on agar medium with different concentration. Compared with the 6 concentration gradients in the organic insect-rearing box of 5.5cm diameter, the 1g : 100ml concentration of the agar were the most appropriate experimental condition.3) The effect of temperature was crucial on the development of B. tabaci. Compared with the 6 concentration gradients, the developmental duration of B. tabaci nymphs was significantly shorter on the detached-leaf of host plants than that in CK, and the size and hatchability and emergence rates were nonsignificant difference between test treatments and CK at 25℃.4) A local parasitoid of B. tabaci was preliminarily identified as Amitus sp., which was described and illustrated for its male and female individuals with their morphological characteristics.5) The reproduction of Amitus sp. was parthenogenesis. The peak time of emergence was in 6:00-10:00 of a day. The general process included 4 actions, that was, searching, evaluating host, ovipositing and combing. In these 4 actions, the most frequent one was searching which is 28.08% of the total frequency. It took most time to comb, with 44.65% of the total time. Amitus sp. preferred to lay the egg in the 1st and 2nd instar nymphs of whitefly. They produced the highest parasitism rate of about 78.33% in the 2nd instar nymphs.