Research On The Dosage Forms Of Microbial Pesticides Against Powdery Mildew Of Tobacco

Tobacco powdery mildew is a common and widely occurring fungal disease in tobacco.At present,most of the plant disease inhibitors are through chemical ways,and become the main methods to prevent the outbreak of powdery mildew.But with the environmental pollution and pesticide residues being paid more and more attention,experts point out that the use of chemical pesticides should be reduced and the biological control of pollution free dyeing should be studied.In this paper,the liquid fermentation products have been screened for the high resistance to powdery mildew of tobacco with D1 Bacillus as the main test strain.The optimization of liquid fermentation,optimization of solid fermentation,the development of biological pesticide formula,preparation of dosage form and the effect of use are analyzed.1.Many groups of D1 screening experiments on Bacillus amylum producing medium were carried out,and Potato sucrose medium was the best medium.Under the fermentation conditions,the optimum fermentation temperature is 28 degrees,and the shaking time is 120r/min.The fermentation time is 48h.It can produce far more active bacteria than other formula media.Under this condition,the number of living bacteria of the fermented product is 8.5×10~9cfu/m L,It has reached the national standard of agricultural microbial inoculants(GB 20287-2006).2.In rice,soybean meal and wheat bran as mixed solid fermented raw materials,the optimum conditions are as follows:mixing proportion rice:soybean meal:wheat bran is 3:3:1,fermentation water quantity is 1.5 times of medium,fermentation temperature is 30℃,and the length of fermentation is 48h.Under these conditions,the highest number of viable spores was found in the fermentation products,indicating that the activity of the products was the highest.3.Inspired by the preparation method of compound microbial pesticides,tea saponin is selected as the natural material in nature.The highest resistance to disease was achieved when the proportion of D1Bacillus starches fermentation broth and 2%concentration of tea saponin aqueous solution was 7:3,and the bacteriostasis rate was increased by 25.26%compared with single fermentation broth.4.the single D1 Bacillus starches fermentation broth was prepared for the preparation of water forming agent,powder,wettable powder and granule,and the compound microbial pesticides containing tea saponin were prepared for the preparation of water forming agent,wettable powder and granule.In a variety of dosage forms,a pot experiment was carried out to test the effect of the reagent against powdery mildew of tobacco.The data showed that the best effect was compound microbial pesticide,the resistance rate of the potted plant reached 82.05%.The effect of the compound microbial pesticide under the same dosage was slightly higher than that of the single fermented liquid,the effect of water agent was increased by 2.88%,and the effect of wettable powder was increased by 2.04%,the effect of granule was increased by 1.56%.