| The speciesand host plants of Bemisia tabaci ( Gennadius) were investigated and identified from 2005 to 2006 in An yang Region. All of the host plants can be classified into 4 grades according to the damage degree caused by B . tabaci . There were two main species: Bemisia tabaci , Trialeurodes vaprorariorum .There were 66 species of host plants of B . tabaci belonging to 18 families , among them there were 8 species belonging to Leguminosae ,8 speciesto Solanaceae , 9 species to Cruiciferae , 9 species to Cucurbitaceae , 10 species to Compositae , 2species to Chenopodiaceae ,2 species to Amaranthaceae , 4 species to Convolvulanceae , 3 species toMalvaceae , 2 species to Euphorbiaceae , 2 species to Euphorbiaceae, 1 species to Moraceae , 1species to Meliaceae,1 species to Punicaceae ,1 species to Ebenaceae,1 species to Verbenaceae, 1 species to Oleaceae ,and 1 species to Cannabinaceae.among which Cucurbitaceae ,Solanaceae , Cruciferae and Leguminosae are the major families. B . tabaci is more serious in downtown.It drawn some conclusions through studying in lab and field. As followed: In the temperature range of 16—35 c C,total development duration from egg to aduh decreased as temperature increased,varying from 48.89d at 1 5 c C to 17.79d at 28oC.When the temperature above 35 ,thrips can not normally develop from nymph to adult.It showed that the most comfortable temperature of Bemisia tabaci , upgrowth was between 22 and 280c .Temperature affected significantly of B. tabaci .Under different constant temper atures from 16 to 32 cc the longevity of the adults varied. The longevity of the adults was shorted gradually with the increase of temperature. From 16 to 32,the average longevity of the adults was 42.12d,39.57d,28.06d,23.24d,17.01d,12.84d respectely.It was a peak value at 19 cc,152.33 eggs/female.Being lower than or being more than 19 cc,fecundity all descend.The relative humidity the developing of B. tabaci. It computed the period of B. tabaci, eggs was 6.62d ,7.82d ,7.51d,6.86d respectely at 30%,5 0%,70% and 90%RH with a constant temperature of 25 cc,respectively;the period of nymph was 12.66d , 11.81d, 11.83 d, 11.88d respectely; the period of adult was 21.35d ,19.86d , 19.41d, 19.63d respectely. The suitable range of relative humidity for the population growth of this insect ranged 50%. Survival of eggs,the first instar nymphs,third instar nymphs and adults was significantly afected by humidity.Temperature significantly affected the development of B. tabaci. At the range of temperature 16 to 32,the developmental durations were decreased with the increase of temperature.According to the priority law, the threshold temperature and effective temperature sum of egg, the first instar nymphs,second instar nymphs , fourth instar nymphs,third instar nymphs and egg-to-adult were 12.4℃,90.0 degree.day; 12.5℃,27.8 degree.day; 10.5℃,48.0 degree.day; 12.4℃,33.6 degree.day; 11.1℃,41.2 degree.day;12.4℃,263.8 degree.day respectely.Therefore,begin to develop above 11℃.Studied on the dynamics of B. tabaci. In the field of Euphorbia pulcherrima Willd in this paper. From Middle ten-day of period of July to last ten-day period of October,there are two peak of Euphorbia pulcherrima Willd, population, last ten-day period of August and first ten-day period of September. last ten-day period of October hereafter endanger in the glasshouse. At the heavy rain day,the population drop,contrarily it increase.The field trial showed controlling techniques that Proceeding the plant quarantines;planting the resisted pest breed;protecting natural enemy;using the yellow sticky traps to imago;carrying out agricultural controlling with chemical controlling in the mainly controlling periods. Using the medicine when occurrence to a litter of B. tabaci. The high-efficiency and low-toxity insecticides should be selected. Through comparing the effect of five pesticides on Euphorbia pulcherrima Willd, ,s in the fields ,it showed that the effect of Abamecitin, Imidacloprid, Buprofezin is better. The control effect on the adults and larvae of B. tabaci was over 90% after seven days. The controlling B. tabaci can replace with use this three pesticides. |
PDF Full Text Request