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Study on Organic Prevention and Control Technologies of Bemisia Tabaci (Gennadius) in Facilities Cultivated Vegetables at Turpan

Author: ChenDan
Tutor: MaDeYing
School: Xinjiang Agricultural University
Course: Zoology
Keywords: Bemisia tabaci vegetables in greenhouse ecological control technologies physical control technologies bio-control technologies
CLC: S436.3
Type: Master's thesis
Year: 2011
Downloads: 110
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Abstract

The ecological control technologies, physical control technologies and bio-control technologies were studied based on the rule of organic production and the theory of IPM, main results are as the following:1. The traping and killing effect of different densities of yellow trap as well as color differences are studied in heliogreenhouses to Bemisia tabaci. Results showed that the traping and killing effect of 3m space between yellow traps is the best with 99.5% population decline rate after 30d, lined with 6m and 9m at 87.27% and 44.92% population decline rate, respectively. Combining population decline rate of B. tabaci on plant and the space between yellow traps fitted the regression equation of y=-1.7404x2+11.392x+79.874 (R2=1). It suggested that the population decline rate of B. tabaci on plant decreased along with the increase of spaces between yellow trap after 3m. whereas the population decline rate of B. tabaci on plant decreased very slowly in distance of 3-5m, this may be the most economic space between yellow trap in greenhouses. In comparison of two different yellow trape colors, both yellow trap with golden and orange colors showed distinct traping and killing effect to B. tabaci, however the effect of yellow trape with golden color is significant better than that of orange color. Therefore, the ideal control effect could be obtained to hang golden color trap in 3-5m space between traps at the initial period of B. tabaci occurrence, as the density of B. tabaci is less than 5 heads/leaf.2. The combination of suction machine and yellow sticky trap showed remarkable control effect to B. tabaci. The suction operation not only decreased the amount of B. tabaci, but also enhanced the trapping effect of yellow sticky trap. There are 1.17-fold differences before and after suction in the trapping amount of B. tabaci. The highest trapping rate of increase reached to 309.2%, and the cleaned suction rate is 86.08%. The population decline rate of B. tabaci on cucumber is around 45.54%.3. The study of ecological control showed that, there are siginificant effects in the trapping of B. tabaci with the melon and cucumber among of hot pepper, the trapping rates for both baitcrop reached to 97.56%. However, the trapping effect of melon looks better than that of cucumber since the amount of B. tabaci and egg laying on melon are significant higher. The different orientation of tobacco and piemarker showed very good trapping effect to B. tabaci, and the trapping rate is above 79.94%.4. The combination effects of Encarsia Formosa Gahan and yellow sticky trap in the control of Bemisia tabaci on tomatoes in green house showed that, Encarsia Formosa was released once after every 5-7days and lasted for 5 times under controlled condition, which the amount of Bemisia tabaci adults are less than 3 heads/plant, and the larvae are less than 2 heads/plant. The release amount of Encarsia Formosa each time is about 5 000 heads/mu. It suggested that the average emergence rate of Encarsia Formosa is approximately 84.35%, and the highest parasitic rate is 73%. It is about 35 d between the initial release date and the foundation of population, and it took about 2 months to take over the Bemisia tabaci population. The investigation of vertical distribution indicated that, Encarsia Formosa mainly located on the middle and low parts of the plant during the early stage of tomato growing; and moved to the middle and top parts of the plant in the late stage of tomato growing along with the movement of Bemisia tabaci. The regularity of horizontal distribution is high -low-high-low-high from east to west (from door to inside).5. The investigation suggested that there are two parasitic wasp in Turpan region, Encarsia Formosa Gahan and Eretmocerus mundus Mercet. The advantage population on tomatoes in green houses is Encarsia Formosa, and it is very abled to parasitize B. tabaci, the parasitic rate reached to 94.39%. It seems that the parasitic rate is higher in the direction of southeast than that of the direction of northwest.The advantage population in field is Eretmocerus mundus in Turpan city and Shanshan country. The parasitic rate in Turpan region is around 20-33.3%, and Eretmocerus mundus showed strong control effect to B. tabaci, it is sigcificntly higher than that of Shanshan country.

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CLC: > Agricultural Sciences > Plant Protection > Pest and Disease Control > Horticultural Crops Pest and Disease Control > Vegetable pests
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