A website from UGA Cooperative Extension

Slides from February Onion Disease Update

Written by

Chris Tyson

February 13, 2020

We had a great turnout for our Onion grower crop update this week. In case you missed it, here are the highlights below. Many thanks to Dr. Bhabesh Dutta, UGA Extension Plant Pathologist, for sharing this important information.

Botryis leaf blight showing up

Here is a large botrytis leaf blight lesion that has sporulated and the “cloudy halo” appears around the initial spot on the leaf. The development of these symptoms increases during periods when leaves stay wet for several hours at a time.

Botrytis leaf blight can sometimes start off as small “specks” on onion leaves as pictured here. As the disease progresses, these “specks” can become larger and develop what looks like a “cloudy halo” around them.

Fungicides for Botrytis leaf blight

Here is the most recent ranking of labeled fungicides for protection against Botrytis leaf blight.

Stemphyllium Leaf Blight is out there, too.

Fungicides for Control of Stemphyllium

Onion Downy Mildew has not been detected yet. Here’s what you need to protect your crop with:

Downy Mildew sporulation on a Vidalia Onion leaf in 2018.

Posted in: Botrytis, disease, downy mildew, Stemphyllium, Vidalia Onion

Tags: botrytis leaf blight, downy mildew, Stemphyllium leaf blight, Vidalia Onion

Chris Tyson

I am the UGA Extension Onion Agent and Coordinator of the Vidalia Onion and Vegetable Research Center.