Methods for screening new Ampelomyces strains to be used as biocontrol agents against grapevine powdery mildew

Grapevine powdery mildew is a key disease all across Europe and is currently controlled almost exclusively using fungicides. To develop a new biofungicide product against this disease, caused by Erysiphe necator, a large culture collection of Ampelomyces strains collected worldwide from different powdery mildew species was screened to assess for the first time the level of variability of different characteristics of these biocontrol agents known to occur as natural mycoparasites of powdery mildews in the field. This preliminary screening revealed a considerable diversity in many characteristics of different Ampelomyces strains including both culture patterns and mycoparasitic activities against the asexual and sexual stages of E. necator. The screening protocol developed in this work could be used in further studies on Ampelomyces in order to develop new effective commercial biofungicide products against powdery mildew infections of grapevine and other crops.