- Disease Update by Bob Kemerait
- CORN: No southern rust has been found in Georgia to date. Apparently, there is not a lot in Florida either. Spores from Florida are typically a threat to our corn crop. Little disease there means lower risk here in Georgia. Jason Brock and I are seeing a fair amount of Northern Corn Leaf SPOT, Southern Corn Leaf Blight and some Northern Corn Leaf BLIGHT on samples that have been submitted. To date, most of the disease has been confined to the lower, older leaves and little seems to be aggressively spreading. I am seeing a fair amount of CORN SMUT (Ustilago maydis). This can cause some loss on a susceptible variety, but is often cosmetic. NOTE: Corn smut is REALLY cool looking and the Aztecs ate it (and it is still popular in Mexico) at “huitlacoche”. Sharing pictures of it and stories about the disease and the delicacy are interesting in Extension outreach to people in your county beyond farmers.
- MANAGEMENT for CORN: Still not southern rust, but conditions are perfect. Still not sounding the alarm for fungicide application; however many growers are spraying because 1) conditions are perfect, 2) they are worried about missing it, 3) corn is at tassel or beyond and 4) if we do need to spray quickly it may be tough to line up a plane. Again, I am not calling for general sprays because the rust disease has not been found here and it not rampant in Florida. However, caution is the better part of valor in some situations.
- PEANUTS: Still getting reports of Aspergillus Crown Rot in some fields. Often times linked to farmer-saved-seed. Tomato spotted wilt is showing up; it remains to be seen just how bad (or good) it will be this year. Conditions are now PERFECT for white mold (Stem rot, Nickster…….) Soils are moist and heating up and many are getting afternoon rains. TIMELINESS IS CRITICAL. DO NOT GET BEHIND ON WHITE MOLD OR LEAF SPOT THIS YEAR! Eddie Beasley has sent me pictures of leaf spot developing on “volunteer peanuts”. Tucker Price has sent pictures of white mold on soybean….
- COTTON: Bacterial blight was found on NG 5007 in Marion County. Bacterial blight has been reported on DP 1747NR from Irwin County and also Colquitt County. Bacterial blight is reported on PHY 444, DP 1646 and NG 5007 from SW Georgia. BOTTOM LINE: Conditions have been PERFECT for bacterial blight this year and outbreaks this early are of serious concern. All outbreaks have been on varieties we know to be at least somewhat susceptible. I encourage you to continue to educate the growers and to help them identify the disease and other problems. Nothing can be done now about bacterial blight. Growers should avoid moving tractors and equipment through those fields when plants are wet.
- COTTON: Significant Fusarium wilt is being reported from Colquitt County. PLEASE continue to help growers identify this disease and alert me about it.
- Soybeans: no soybean rust found to date in Georgia.