Applied Research On Beauveria Bassiana YS03 To Lissorhoptrus Oryzophilus

1.Studies on the harm loss and economic threshold of Lissorhoptrus oryzophilus Kuschel in GuizhouIn order to control the Lissorhoptrus oryzophilus, efficaciously. The tests on the damage and economic threshold of rice, was carried out by envelop modifying the density of L. oryzophilus. Infected rate of rice leaves, larval density, tillering number and single yield difference was significant, spike number, grains per spike and 1000-grain weight had not significant difference, regression equations among the loss rate of yield and infected rate of leaves were established, after rice transplanting 5days, 10 days, 15 days, 20 days, the economic threshold for infected rate of rice leaves were 59.65%?52.97%?50.96%?48.52%. Regression equations among the loss rate of yield and the adult density and among the loss rate of yield and the larval density were established, the economic threshold for the adult were 20 adult per square meter, the economic threshold for the larval were 130 larval per square meter. This results has important guiding meaning to prediction and prevention of Guizhou.2. Optimization of sporulation medium of Beauveria bassiana YS03 controling rice water weevil, Lissorhoptrus oryzophilusThe formula of Beauveria bassiana YS03 culture mediums were improved by single factor test and response surface methodology. The important factors influencing the spore yields, which identified by initial screening method of single factor test,were peanut, wheat bran and corn flour. Ingredients were obtained through Box-Benhnken central combination design and RSM. The results showed that the optimum yields conditions of spore are as follows: peanut: wheat bran: corn flour=2.6:3.5:3.9. After experimental verification, the maximum predicted value was consistent with mean value and optimal medium was as 1.92 times as that of PDA medium.3. Research on Beauveria bassiana YS03 to Lissorhoptrus oryzophilus the excellent prevent dateAdult, number of feeding scars and oviposition was significant, Length of feeding scars had not significant difference. 24 th experimental day, application of 10 days after planting, the mean corrected death rate of adult was 100%, 7th experimental day,application of 10 days after planting, the mean corrected death rate of adult was86.67%, 15 th experimental day, application of 10 days after planting, the mean corrected death rate of adult was 60%.To survey the field number of adult and oviposition in the 5th, 7th, 10 th, 15 th,20th. The results show, adult and oviposition was significant in different date, most adult number in 7 days after planting, most oviposition number in 10 days after planting. So, in 7 days after planting to spraying Beauveria bassiana YS03 had excellent control effect.4. Studies on Beauveria bassiana YS03 to Lissorhoptrus oryzophilus the different application methodThe control efficiency for Lissorhoptrus oryzophilus by Beauveria bassiana in different application method to adult, larva and feeding scars. result display, both spray and dusting have excellent control effect.different application method to adult, larva and feeding scars was not significant,the control effect to adult of Lissorhoptrus oryzophilus is more than 65%, to larval is more than 80%.