Study On Biological Control And Biological Characteristics Of Ephestia Elutella Hübner

The biological characteristics, artificial feedings and the biological controls of Ephestia elutella Hübner were studied at laboratory of Institute of Tobacco Science Research and tabacco store of Yuxi and Chuxiong tobacco factory during 2004～2008. The main results were as follows:1. The biological characteristics of Ephestia elutella Hübner and its regularity of outbreak in Yunnan province were distincted, and then 3 artificial feeds were screened. 3 generations of Ephestia elutella Hübner was happened in Yunnan province every year. Group Ephestia elutella Hübner was easy to feed and breed at 23°C～26°C temperature and 75%～85% relative humidity.2. 3 fine stains were screened from 752 Bacillus thuringiensis which were separated from 801 redrying tobacco leaves, 39 cured leaves and 91 soil sampls. 7 Bt contained cry I toxin gene and 21 Bt strains contained cryV gene by PCR method. The bioassay toxicity of Bt isolates containing cry I and cry V gene was determinated to Ephestia elutella Hübner second instar, the results showed that corrective mortality of insect was over 94% at 9d after inoculating isolate 5,10 and 18.3. Parasporal crystals of 3 Bacillus thuringiensis strains were extracted by the method of liquid diphasic separation. Under scanning electron microscope and transmission electron microscope, it was found that different strain had different morphology crystal and quantity. The pattern of SDS-PAGE electrophoresis was also different, it indicated that isolate 5 had two clear bands of 43kD and 15kD, isolate 10 had three clear bands of 43kD, 15kD and 19kD, and, isolate 18 had three clear bands of 43kD, 23kD and 15kD.4. Fine Bt isolates can be used to control Ephestia elutella Hübner. The control effect on isolate 5, 10 and 18 from 1 to 5 instar larva was over 95% on average. It was concluded that the treatment effect on the stored tobacco leaf isolate 5, 10 ,18 bacterium preparation by method of even spraying was better than other treatments.5. The chemical component in tobacco leaves sprayed Bacillus thuringiensis preparation was no obvious difference with CK. It can improve aroma component of tobacco leaves. The tasted conclusion could be drawn that the aroma quality, aroma volume, offensive odor was improved compared to contrast, but there was no distinct different with irritancy, physiological strength and remaining taste. The results showed that it can improve quality of tobacco leaves by spraying Bacillus thuringiensis on isolate 5,10 and 18 preparation .