Selection And Screening Of Tobacco Antagonistic Actinomyces Against Phytophthora Parasitica Var. Nicotianae

Tobacco black shank is one of the more important diseases during tobacco production. The tobacco area of black shank disease is 76373hm2 and the yield loss is 2. 86926×10~7kg counting up to more than 1×10~8RMB per year in China. The normal control strategies are main in using chemical fungicides. Considering that biological fungicide is better compatible with agricultural production, environment protection and society development, exploiting biological pesticide or fungicide has become one much important way to control farming and forest disease in world. This paper was designed to screen efficiency strains of Actinomyces spp. from special soil to control tobacco blank shank through separating in lab, identifying by antagonizing andtesting using pot plant and using field plant. The test results as following.1. After sampling from special soil and separating, purifying strains in petri dish, we obtained 101 initial strains of Actinomyces spp. and 6 strains with special antagonize effect: A3,A4,A6,A10,A12,A24.2. the initial stains for control of the pot plant were A3,A4,A6,A10,A12,A24 and A15 which is with bigger clony and smaller inhibition zone. Among them A6 had the best control effect up to 55. 26% and A5 the worst as 14. 40%.3. We tested the control effects using fungicide agents which were made of subculture strains of A4,A6,A12,A24 in fields of tobacco science research institute of GuiZhou province. Results indicated that the strains of A 4 and A24 were good for control of the tobacco black shank in these tests.