What is in this article?:
- Frequent rain making disease control difficult in Georgia crops
- Can reduce yields
• The torrential rains Georgia has experienced in recent weeks have created perfect conditions for fungal and bacterial diseases on peanuts, cotton, corn and soybeans.
AN INCREASING number of COTTON fields in Georgia are being confirmed with target spot. This is likely a combination of continued wet, cloudy weather and the developing canopy of the crop.
Can reduce yields
Southern corn rust can reduce yields by reducing grain fill and weakening stalks. UGA plant pathologist Dewey Lee and I both believe that growers are fairly safe if the crop is protected until the dough stage with a fungicide.
Northern corn leaf blight and southern corn leaf blight are also found regularly.
Asian soybean rust has been found in kudzu in Appling and Miller Counties and in northern Florida and in central Alabama. Conditions are extremely favorable for rust and other diseases to spread to soybeans.
Georgia soybean producers should be prepared to make a timely fungicide application to their crop sometime between bloom and early pod development stages.
I strongly believe that with the risk to rust, anthracnose, frogeye leaf spot, and Phomopsis pod and stem blight, judicious use of fungicides is quite important.
Conditions should be excellent for the development of target spot in cotton again this season. Although none has been diagnosed yet in Georgia, it has been found in the Panhandle of Florida.
To reduce the impact of target spot, the crop must be managed to reduce rank growth and by using fungicides before the disease is well established in the field. This should be done when good coverage of the crop is possible.
Based upon data from last season (which could change), the single best time for an application of a fungicide is the third week of bloom.
To effectively manage target spot, growers should continue to scout their cotton and notify their UGA county Extension agent of suspicious leaf spots.
Ascochyta wet-weather blight is also very common this year. It can look similar to target spot. Cotton growers who have fields where target spot has been problematic in the past are likely to see it again this season. These growers should be very careful in deciding if and when to use a fungicide.
I hope the rains fills Georgia ponds, but we could all use a little dry weather now.
(Bob Kemerait is an Extension plant pathologist with University of Georgia Cooperative Extension.)
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