White mold on peanuts in Columbia County. 7/14/13
We have been dealing with white mold of peanuts here in Columbia County for several weeks, particularly in early planted peanuts. Dr. Nicholas Dufault, Extension Plant Pathologist recently reported ” We can expect to see more disease with the current environmental conditions throughout Florida. Growers should continue recommended white mold fungicide applications.”
Additionally, Dr. Dufault indicated that “The weather is perfect for leaf spot development and we have recently identified the presence of early leaf spot in Marion County. It is only a matter of time before this disease and late leaf spot develop in other counties. It is important to maintain good leaf spot spray programs while focusing on white mold control.”
I have had many calls from area farmers about leaf spots in their fields, and have sent several samples to the Pathology Lab and none were positive for early or late leaf spot. However as Dr. Dufualt suggests, I expect extremely high leaf spot pressure in the coming weeks.
The last I looked at rainfall records, we recieved measurable rainfall 23 of the prior 26 days at the Live Oak FAWN station, and I have suggested to many of the farmers that even our low risk, well rotated fields are a high disease risk due to the weather conditions. In 2012 some of our farms went to night sprays to control white mold and we had very poor leaf spot control. While they had excellent white mold control, leaf spot control was very poor. Leaf spot is a major disease, and we need to make an effort to get the best control we can in a season such as this. Potentially more effort than we make for white mold control is warranted.
For leaf spot control, I suggest we tighten up the spray interval to applications every 7-10 days, and try to get good LEAF coverage. This is of course dependent on a window to spray and being able to access fields. Many farmer are calling to ask if I think “the chemical washed off.” I don’t know the answer, but this is a good indication that we are probably not getting much drying time with these sprays. We saw fields last year that were unharvestable due to poor leaf spot control. I suspect very similar results this season if we don’t manage to meet the disease potential.
Defoliation of peanuts due to leaf spot in September 2012
Many of our area farmers are making night sprays for white mold/stem rot and rhizoctonia. This video is a ride along with a couple area farmers as they make their applications.