Invasion Of Pests B. Tabaci Biotype B On The Host Plant Physiological Adaptation Mechanisms

Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) biotype B is a key pest of greenhouse vegetables, ornamental crops and cotton in many regions of the world and an alien invasive species in China. The host plant species of B. tabaci Biotype B has been increasing with the spreading of its invaded areas. Further, in some areas, such as north China, the competition between B. tabaci Biotype B and its co-existing, closely related species had been observed. In order to understand the invasive mechanism of B. tabaci Biotype B, The activities of some detoxification enzymes, the lactate dehydrogenase activity, the content of trehalose and protein of laboratory populations of B. tabaci Biotype B on cotton, poinsettia, eggplant and tomato were determined in this study.The results were as follows:1. the frequency of B.tabaci biotype B on cotton and poinsettia with theα-NA carboxylesterase activity less than 60mOD/(mgprot?min) were 95% and 70% respectively. The frequency at every range of the activity of carboxylesterase in B.tabaci biotype B on tomato and eggplant focused on 10%~40%.2. The frequency of B.tabaci biotype B on eggplant and cotton with theβ-NA carboxylesterase activity less than <30 mOD/(mgprot?min) were 85% and 75%, The frequency of the activity ofβ-NA carboxylesterase at the range of 30~40mOD/(mgprot?min) was 50%, and that of poinsettia with theβ-NA carboxylesterase activity less than <20 mOD/(mgprot?min) was 50%.3. The total activity of carboxylesterase in B.tabaci biotype B on tomato was the highest, 1.49 times of that on cotton, on eggplant it was 1.33 times of that on cotton, and 1.20 times on poinsettia.4. The ratio ofα-NA carboxylesterase activity toβ-NA carboxylesterase activity in all host populations were more than 1, which indicated that the hydrolyzation toα-NA was higher than that ofβ-NA in the 4 host populations. As the methods of Gao Xi-Wu to the insece classify, the tomato and cotton species was different to poinsettia and eggplant species, which were mainly CE1. 5. The activity of acetylcholinesterase in B.tabaci biotype B on eggplant was significantly (p<0.01) higher than the activity on other 3 host populations. The frequency of B.tabaci biotype B on eggplant with a acetylcholinesterase activity of >4U/mgprot was 85%, significantly different form other 3 host populations.6. The glutathione S-transferase activity in B.tabaci biotype B on eggplant was the highest in the 4 host populations. The difference of glutathione S-transferase activity between populations on eggplant and the other 3 was significant (p<0.01). The frequency of B.tabaci biotype B on eggplant with a glutathione S-transferase activity of >170U/mgprot was much higher than on other 3 host populations.7. The activity of LDH in B.tabaci biotype B was different among the three host plants.It was the highest on tomato.The difference of LDH activity between populations on tomato and eggplant was significant (p<0.01).8. The trehalose content in B.tabaci biotype B on cotton was the highest in the 4 host populations. The difference of trehalose content between populations on cotton and eggplant was significant (p<0.05). The frequency of B.tabaci biotype B with a trehalose content of 11~12ug/adult was high in the 4 populations, the frequency was different among the 4 populations at other extents.9. The protein content in B.tabaci biotype B on cotton was the highest in the 4 host populations. The difference of protein content between populations on cotton and eggplant was significant (p<0.01). The protein content frequency of B.tabaci biotype B on eggplant and tomato distributed mainly at 2~4ug/adult, while it was comparatively equality on cotton and poinsettia.These results indicated that B.tabaci biotype B on different host plants had definite physiological plasticity. This study can help to reveal the ecophysiological basis of having broad host range and excellent adaptability to hosts for the biotype.