辣椒白粉病生防菌株Bs2的筛选鉴定及田间防效研究

摘要

从40份农田土壤中分离筛选出了69株芽孢杆菌对Fusarium oxysporum、Botrytis cinerea、Colletotrichum gloeosporioides、Cylindrocarpon具有拮抗作用,其中Bs2菌株发酵液稀释50倍(5.6×107cfu/mL)后处理,连续用3次后的第7天,对辣椒白粉病的防治效果达到60.77％,略低于化学农药粉锈灵(0.8g/L)的防治效果.通过形态特征观察,生理生化试验及16S rDNA序列分析,Bs2与菌株Bacillus pumilus SBT2-9的相同,其16S rDNA序列同源性高达99.41％,被鉴定为短小芽孢杆菌.%69 strains antagonistic against Fusarium oxysporum, Botrytis cinerea, Colletotrichum gloeosporioides, Cylindrocarpon, were screened from the 40 field soil samples. A strain Bs2 with 50-fold dilution(5.6 x lO'cfu/mL) of the fermentation broth gave good control efficacy of 60.77 % against hot pepper powdery mildew in the field test after 3 sprays, which was lower than that of fungicide triadimefon ( 0. 8 g/L). Bs2 was identified as Bacillus pumilus on the basis of its morphological, physiological and biochemical characters as well as its sequence analysis of 16S rDNA with 99.41 % similarity to B. Pumilus SBT2-9.