Changes Of Tomato Qualities Caused By Injury Of Bemisia Tabaci And Toxicities Of Insecticides To Its Nymphs

The Bemisia tabaci (Gennadices) is an important pest that have outbreaked andcaused severe damage worldwide through the last 20 years, it has been an importantinset pest of economic crops of vegetable, horticulture, cotton et al in our country,it has caused serious losing. In order to explore mecharnism and disaster regulation of B.tabaci, the tomato qualities damaged by B. tabaci were studied in this paper. At thesame time, bioassay test of two pesticides and technique in the field were studied. Themajor results were as following.1. The influence of appearance and chemical components of tomato injured bydifferent population of B. tabaci was studied.When the population of B. tabaci was 200 individual,400 individual and 800individual per plant, the rates Of rolling leaves increased significantly by 10.27 %,34.37% and 85.77 %. The chlorophyll contents of the tomato decreased at differentpopulation of B. tabaci. The contents or total sugars incraised significantly when thetomato was affected by B. tabaci in different density, the amount of the total sugarsdecreased above 37%. When the infection was more severe, the contents of the Vc ofthe tomato decreased more,the raising ratio is by 55.16% at most.The Protain contentsof the eggplant significantly increased by 5.1676 mg per 100g at 200 individual perplant,but it reduced 5.0152 mg and 5.4308 mg per 100g at 400 individual and 800individual per plant.2. Toxicities of two insecticides and drug effect test of the nymph stage of B.tabaci.Bioassay of 10% imidacloprid and 2.0% abamectin to Bemisia tabaci, the studyresults showed that the low nymphs of toxicities of two insecticides were lower than thehigh nymphs of B. tabaci, the amount of Lc₅₀ were 15.97ug per ml,4.97ug per ml atthe low nymph stage and 16.52ug per ml,5.12 ug per ml at the high nymph stage. Atthe same time, control technique of B. tabaci in the field were studied prelimily, the effects of seven insecticides against B. tabaci were showed that 0.6% emamectinbenzoate, 0.3% azadirachta and 1.8% abamectin were 93.91%, 98.21% and 88.64%respectively. 10% imidacloprid had some efficacy on B. tabaci.