ROW CROP DISEASE UPDATE
Dr. Bob Kemerait, University of Georgia Extension pathologist, gives a row disease update below:
Peanuts: We are beginning to get an increased number of peanut samples to the diagnostic lab with white mold and Dr. Brenneman reports that epidemcis of white mold are very active in our area. Rainfall and warm temperatures will continue to fuel outbreaks of white mold. Also, we are finding outbreaks of early leaf spot in our peanut plots in Tifton and in Attapulgus. We are also receiving leaf spot samples in the disease clinic. Now is the time to be prepared with your fungicide programs.
Soybeans: Asian soybean rust is found in kudzu throughout much of the Coastal Plain in Georgia. It has also recently been detected in mid-state Alabama which should be of interest to many of our soybean producers along the Alabama border (see www.sbrusa.net). To date, I can also report that soybean rust is active in soybean plots in Brooks County and we have a fierce epidemic of soyeban rust in our sentinel plots in Attapulgus. Bottom line: recent rains will only further fuel this disease; growers along the Coastal Plain are advised to protect their crop with fungicides by early pod formation growth stage and as they fight insects and other problems.
Cotton: Target spot (Corynespora leaf spot) is reported in Mitchell, Cook, and Berrien County in our plots. The amount of disease at the Stripling Irrigation Park is amazing; two weeks ago very little but today up to 50% defoliation in some plots. Fungicides are working well…. Bottom line is that there are MANY places where target spot is NOT a problem and a fungicide is likely not needed (yet). However, where cotton follows cotton in rotation, where the disease was a problem last year, where grower uses overhead irrigation, especially in reduced tillage systems, and in southwestern part of the state, BE AWARE that this disease can be a significant problem and that late fungicide applications are not much better than no fungicide…. I hope to have a field day at Stripling soon so that you all can see the difference a fungicide application can make.
Dr. Kemerait discusses where target spot is showing up on On The Farm at OTF-KemeraitTargetSpot1 and research to control target spot at OTF-KemeraitTargetSpot2
PROGRESSION OF TARGET SPOT
Corn: LATE PLANTED CORN- I may be wrong! I have told many of you to wait until first tassel to spray fungicides on late planted corn to control southern rust and Northern corn leaf blight. In looking at fungicide plots on corn planted in late May, only the V6 growth stage applications have slowed the spread of NCLB; waiting to tassel was too late…. My advice now: If late corn is growing near fields where disease has been severe this season, consider spraying at V6; otherwise watch carefully and consider benefits of a V6 vs VT spray.
