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Welcome / Downy mildew observed in Blairsville, GA

All,

Welcome to the UGA Extension Viticulture Blog.

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Please see note, below, from Phil Brannen:

Downy mildew was confirmed at the Blairsville research station today.  This is pretty early, and infections may not be uniform across the region.  However, please scout your grapes and consider adding more efficacious fungicides to their spray programs.

Fang, a graduate student with Harald Scherm and I sent this information.  He is running the Italian downy mildew model, and it seems to be tracking with the initial symptoms.  Again, producers should be scouting and considering their spray choices based on a field assessment and current weather conditions (and predicted weather conditions).  We could have a nice crop this year.  Hate to see us lose ground to mildew.

Fang writes:

“The model predicted the first symptom on 4/4, but the latest simulated symptom is on 5/6. In my baiting experiment from 2016 leaf litters, there is a downy mildew colony on one leaf disk of 4/23-24 batch, indicating the oospores are probably germinating. These are somewhat coincided with the simulation of the model.”

I will follow up with a repeat announcement and link to Dr. Mizuho Nita’s blog, which has very good information regarding efficacious spray materials for downy mildew and other grape diseases, along with a hypothetical seasonal spray program template.

I HIGHLY ENCOURAGE ALL TO SPEND LOTS OF TIME LOOKING AROUND THAT SITE.