Ag Line: Night peanut fungicide sprays boost yield
By Wade Parker County Extension Coordinator

We have some very exciting research taking place in the UGA Department of Plant Pathology concerning spraying peanuts at night. Unfortunately, fertilizer prices continue to climb to astronomical levels. As a result, farmers will be tempted to shorten their peanut and soybean rotations. In other words, these two crops do not require large amounts of fertilizer and will be more tempting to grow. Short rotations have put a cap in yields on many fields in the state, but exciting research by UGA Pathologist Dr. Tim Brenneman has shown that night applications of our white mold fungicides have helped boost yields over 1,000 pounds per acre in fields with poor rotations or heavy soil borne disease pressure.

Dr. Brenneman says, "The big difference is spray penetration. The peanut canopy later in the season is often very dense with the leaves interlocking. It is very difficult for fungicides to penetrate to the soil where it is needed to control white mold."

Dr. Brenneman sprayed the fungicides in his trials at 5:30 a.m., but feels the applications would be just as successful if applied anytime at night. This year he will complete evening applications after the leaves have folded up versus the early morning applications like he did in 2007.

He says, "The difference is in the evenings the leaves are usually dry compared to leaves that have some dew on them in the early morning. So we will have a folded wet leaf in the morning compared to the evening application after dark where we will have a folded dry leaf. We will have to see if this makes a difference. All the data we have generated last year was in the early morning hours, but I feel the big difference for success will be having the leaves folded up."

I will add that the more trouble a grower has controlling soil borne diseases, which are usually related to poorly rotated fields, the more likely a grower is to see a response to night fungicide applications. If a grower has moderate disease pressure or is getting good disease control by spraying in the day, then the grower is not likely to see much of a difference. But if a grower is in a situation where he is getting poor white mold control, then getting the fungicide down through the canopy and to the soil should improve white mold control.

Night applications should work in dry land situations more than irrigated fields because irrigation, or a timely rain, can help move fungicides down to the soil to improve white mold control.

I will say that we only have one year's worth data on this issue. We look forward to seeing the results of this year's work!

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