JOHN P. BEASLEY, JR.
University of Georgia
Extension Peanut Agronomist
The major disease issue on peanut in 2010 in the Southeast was white mold (southern stem rot, southern blight). What made white mold so devastating was how early it became a serious problem, brought on by intense heat. We always expect to have some white mold each year, and the normal time for initiating fungicide applications is approximately 60 days after planting, but Dr. Bob Kemerait, UGA Extension plant pathologist, told growers that, in hind sight, soil-borne disease management should have started much earlier, maybe 45 days after planting. Pay close attention to the maximum and minimum temperatures early in the season this year. If we remain above normal in temperature, expect an early flare up of white mold again. Be prepared to take action quickly with fungicide applications that specifically target white mold.
Texas A&M University
Early June is the time to check for successful nodulation, which is not always a guarantee in Texas. Dig plants carefully, as pulling often pulls off nodules and leads to an underestimation of nodulation. In West Texas, greater than 20 nodules per plant five to six weeks after planting is considered excellent. Response to additional nitrogen may not occur in these cases (depending on prior fertility and yield goal). Nodule numbers of 10 or less will most likely benefit from additional nitrogen. Determine if the nodules are active by cutting them open and looking for pink to dark red color inside. If the nodules are white, wait one week and reexamine the field. Apply additional nitrogen if a majority of the nodules are still white. Apply nitrogen in a single application below 30 pounds per acre, as applications in excess of this can increase pod rot.
North Carolina State University
Weed control will be an important task as we move through June. Hopefully, preplant and preemergence herbicides have held their ground and will continue to provide some degree of residual control. This will be dictated by when we planted and sprayed and when and if activating rains occurred. In the V-C region, we are beginning to pass the window of application – 28 days after peanut emergence – for application of paraquat. If you still fall within the window, paraquat applied with at least 0.5 pints per acre of Basagran (to reduce foliar burn) is a good option for very small weeds and the first flush of pigweeds that might have escaped the residual herbicides applied at planting. Paraquat has a unique mode of action, so it is a good herbicide resistance tool. Selecting the appropriate herbicide and applying herbicides in a timely manner is absolutely critical.
We have experienced an extremely dry spring that persisted into May. One of my concerns with this lack of rainfall is not having enough moisture to activate yellow herbicides, which will set us up for increased grass pressure early in the season. I always receive several herbicide-related calls during this time of year from producers telling me what weeds they have and asking what would be their best attack plan. One of the mistakes producers make is not attacking the grass first. When this occurs, the grass is burned back and becomes more prolific and harder to kill. I encourage producers to spray the grass first. This allows for easily killing the small grass while not affecting the other weeds. In two days, those weeds can then be attacked, but the grass herbicide has had adequate time to begin grass destruction before burning down the other weeds.