Biological control of mulberry twig fungi, Fusarium lateritium f.sp.mori.

建立了一种新的对桑葚枝枯菌（FL）既有拮抗作用又对桑葚无毒的微生物筛选方法。结果证实了该方法的有效性，并分离出了对FL具有拮抗作用的微生物。筛选出抑菌圈最大的菌株39L40C。菌株39L40C经鉴定属于链霉菌属，对所有供试植物病原真菌均形成抑菌圈。当以70 rpm的低搅拌速度振荡培养物时，菌株39L40C的培养物滤液显示出最高的抗真菌活性。菌株39L40C对桑疫病菌的生长有抑制作用，用其培养滤液培养桑疫病菌的大分生孢子，95%以上的大分生孢子不能形成菌落，其原因是孢子萌发受到抑制。菌株39 L40 C在完全干燥的桑葚分支梢上存活14天。以上结果表明，菌株39L40C可作为桑葚桑葚枝枯病的生防菌株。

A new screening method of antagonistic microorganism to mulberry twig blight fungi(FL)and simultaneously not to be toxic to mulberry trees was developed. The effectiveness of this simultaneous screening method was confirmed.Antasonistic microorsanisms against FL were isolated. Strain 39L40C formed the largest inhibition zone among isolated antagonists, was selected. Strain 39L40C was identified as belonging to the Streptomyces genus, and formed an inhibition zone to all test plant pathogenic fungi. When shaking the culture at a low agitation speed of 70 rpm, the culture filtrate of Strain 39L40C showed its highest antifungal activity. Strain 39L40C inhibited the growth of FL with non-sterilized mulberry branches.When macroconidia of FL were cultued in liquid medium including culture filtrate of Strain 39L40C, more than 95 % of macroconidia were not able to form colonies, because the germination of conidia was inhibited. Strain 39L40C survived for 14 days on completely dried mulberry branch tips. These results suggest that Strain 39L40C may act as a biological control agent against mulberry twig blight in mulberry fields.