甜叶菊斑枯病生物防治拮抗菌株的筛选

Isolating of Actinomyce Strains on Biocontrol of Stevia Leaf Spot Disease

从甜叶菊根部土壤中分离到放线菌A0 1和A64两个菌株 ,生长繁殖速度快 ,抗污染能力强 ,抑菌效果好 ,为高效拮抗菌株 .两个拮抗菌株的拮抗活性能稳定遗传 .初步鉴定两菌株为链霉菌属 (StreptomycesWaksmanandHenrici) ,A0 1为黄色类群的一个种 ,A64为蓝色类群的一个种 ,种名未定 .喷施抗生菌剂 ,可有效降低斑枯病病情指数 ,平均防效为 5 6.3 % .A0 1和A64混合构成的抗生菌剂防治效果明显好于两个菌剂单用 ,差异达到显著水平 .抗生菌剂可显著提高甜叶菊叶片产量 ,平均增产 1 8.7% ,尤其在连作小区 ,增产效果更为明显 .

Strains A01 and A64 are two actinomyces isolated from stevia rhizosphere which shows a high growth rate and strong antibiosis activity and these two strains keep their high growth rate and stable antibiosis activity. Taxonomy identification suggested that these two isolates are members of Streptomyces Waksman and Henrici. A01 belongs to yellow group, and A64 is an isolate of blue group.Application of biocontrol agents on stevia leaves could effectively suppress the leaf spot disease. The average control effect is 56.3%. Mixture of A01 and A64 shows a significantly enhanced biocontrol effect compared with the individual isolates. The average yield increasing is 18.7%, and especially in the mono cropping area, yield increasing is more distinct.