From Dr. Bob Kemerait:
“1. Soybean rust continues to spread in our kudzu patches on the Coastal Plain. We know it is in Seminole, Decatur, Lowndes, Montgomery, Telfair, and Appling Counties in kudzu. No detection’s in soybeans yet.
2. Northern corn leaf blight– note two pictures sent to me by Cindy Meadows and Rome Ethredge from Seminole County where some of our earliest corn is planted.
Note in first picture the symptoms, elliptical, cigar-shaped tan-to-gray lesions and in the second the conidia (spores) of the fungal pathogen “Exserohilum tursicum”. Note the conidia are sausage shaped. The conidia have multiple septations and a distinctive scar or “nipple” at one end. This distinctive scar separates the ID from Bipolaris maydis, causal agent of Southern corn leaf blight.
3. The northern corn leaf blight was found in two fields. In one, the crop was approaching tassel and there were a few lesions found scattered in the crop. There is no need to spray that field with a fungicide for NCLB, maybe later for southern rust. The spots associated with NCLB were reportedly much easier to find and the corn is at a younger, V10, growth stage with as much as a month before tasseling. The grower will likely spray the second field with fungicide.
Not surprisingly, both of these fields are planted corn in 2019 and 2020, which increases risk to SCLB and NCLB.
4. Finding a little southern corn leaf blight or northern corn leaf blight in a field is not a problem later in the season. Finding a little southern corn rust in a field, up until R6/hard dough stage could easily be a problem.“