It’s summertime. Thunderstorms have dropped good rain in many places. Humidity swells, which means good conditions for growing cotton and textbook settings for diseases.

The conditions have been ‘absolutely perfect’ for fungal diseases to spread in cotton, including target spot and areolate mildew, said Bob Kemerait, University of Georgia Extension plant pathologist, in a missive to county agents.

There are reports of target spot in south Georgia. Areolate mildew is showing up, too, Kemerait said growers should start scouting the first week of bloom, especially with onset of third week, and “weigh the need for use of fungicides to protect yield.”

Fungicides don’t always increase yield, but for both target spot and areolate mildew, thoughtful use of fungicides can protect the crop and can increase yield profitability.

Target spot up close. (Jeremy Kichler, UGA Extension)

He said Priaxor and Miravis Top perform the ‘best’ against target spot, with Headline close behind.

He said, azoxystrobin is a ‘fair-to-good fungicide’ for control of target spot and good-to-very-good fungicide for control of areolate mildew.

Amistar Top, a combination of azoxystrobin and difenconazole, can be considered when Priaxor, Miravis Top, and Headline are in short supply. The use rate for Amistar Top is 8-11.6 fl oz/A.

Growers should consider protecting their cotton crop from target spot:

Where the crop is suffering from drought or poor growth from other causes, protection against target spot with a fungicide may not be warranted.