Dear Sir/Madams, I would like to ask about effect of temperature & humidity ( & season) on spread of powdery mildew. For grape please find attached. is it same or what or how effects in hazelnut.? Thank you
Outside United States plant disease
In general the powdery mildews are favored by similar environmental conditions. I am sure there are differences between grape and hazelnut powdery mildew. We have super favorable conditions for grape powdery mildew and start controls prior to bloom. In hazelnut, grown in almost identical conditions, powdery mildew gets started very late and not a problem - to a point that we do nothing to manage it here in the Willamette Valley of Oregon, USA.