对桑椹菌核病病原菌有拮抗作用的木霉菌菌株筛选及生防效果试验

Screening and Biocontrol Efficiency of Trichoderma spp. with Antagonistic Effect Against Mulberry Fruit Sclerotiniosis' Pathogen

桑椹菌核病是果桑生产的重要病害,筛选对病原菌有拮抗作用的木霉菌进行生物防治,对确保果桑生产的稳产与桑果的食用安全都具有重要意义。从不同果桑种植区域的桑椹菌核病发病桑园采集桑树根际土壤样品,通过土壤稀释涂布法及形态学特征观察分离到48株木霉菌。采用对峙培养的方法,研究48株初筛菌株对桑椹菌核病病原菌核盘菌(Sclerotinia sclerotiorum)的重寄生能力,筛选出20株具有较强拮抗能力的木霉菌菌株,并进行分子生物学分类鉴定,有7株菌株与哈茨木霉(Trichoderma harzianum)、9株菌株与棘孢木霉(Trichoderma asperellum)、1株菌株与黄绿木霉(Trichoderma aureoviride)、1株菌株与橘绿木霉(Trichoderma citrinoviride)、1株菌株与绿木霉(Trichoderma virens)有较高的相似度。采用玻璃纸法检测20株木霉菌菌株中,有8株菌株的菌丝分泌物对核盘菌处理6 d内的抑制率稳定在80%以上。进一步从中筛选出哈茨木霉Tr16、绿木霉Tr48、棘孢木霉Tr50共3株拮抗作用明显的菌株,利用其发酵液进行桑椹菌核病的田间防效试验,结果显示Tr16和Tr50菌株发酵液的10倍稀释液对桑椹菌核病的防治效果分别为91.27%、82.53%,优于80%多菌灵500倍稀释液的防治效果,具有一定的实用开发潜力。

Mulberry fruit sclerotiniosis is one of the major diseases during mulberry fruit production. Screening of Trichoderma spp. with antagonistic effect for biological control is of important significance in ensuring the stable yield of mulberry fruit production and the food safety of mulberry fruit. Totally 48 strains of Trichoderma spp. were isolated from mulberry rhizospheric soil samples from mulberry gardens with mulberry fruit sclerotiniosis in different mulberry plantations for fruit use by dilution spread method and morphological observation. The hyperparasitic ability of the primaryscreened 48 Trichoderma strains against Sclerotinia sclerotiorum, the pathogen causing mulberry fruit sclerotiniosis,was investigated through the confrontation culture method. Among them,20 strains showed higher hyperparasitic ability. The molecular identification was performed to ascertain their taxonomic position. The results showed that 7,9,1,1,1 strains had higher similarities with Trichoderma harzianum,Trichoderma asperellum,Trichoderma aureoviride,Trichoderma citrinovirideand Trichoderma virens respectively. By applying cellophane papers,the inhibitory effects of hyphae secretions of 8strains in the above 20 Trichoderma strains had relatively stable inhibition rate,which could reach more than 80% within 6days. T. harzianum sp. Tr16,T. virens sp. Tr48,and T. asperellum sp. Tr50 which had obvious antagonistic effect were further screened and the field trial was carried out to investigate control efficiency of these strains on mulberry fruit sclerotiniosis.The results showed that 10 times dilution of Tr16 and Tr50 fermentative liquid had a control efficiency of 91. 27%and 82. 53% respectively,being superior to that of 500 times dilution of 80% carbendazol. It was suggested that Trichoderma strains Tr16 and Tr50 had a certain prospect for future application.