Weather conditions deteriorated during the latter part of the summer in Georgia and little rainfall was recorded at critical stages of the growing season. Scott Monfort, University of Georgia Extension peanut specialist, estimates that as much as one-third of Georgia’s dryland crop has produced very little. So little, in fact, that producers were asked to weigh the decision of whether to even dig the crop or not.
“Some of our crop is in bad enough shape that there’s almost no point in digging them. There’s not a crop to dig in some places,” Monfort says.
Extreme temperatures drove white mold lower on the plant and even underground. Lack of rainfall made fungicide applications less effective.
Nothing To Dig
Georgia’s peanut crop was estimated at 720,000 acres this year, and almost half is grown dryland. Monfort classifies one-third of the dryland crop as suffering through severe drought conditions, one-third as intermediate, which may have a crop but has been heavily impacted by the drought and about one-third that looks “pretty good.”
When Hurricane Hermine moved through South Georgia on Sept. 2, some areas got as much as five inches of rain, but by then it was almost a case of too little, too late.
“It helped a good portion of those (plants) that have peanuts on them that hadn’t matured out. As long as they didn’t come loose in the hull, they should continue to mature,” Monfort says. “Those intermediate and good sections may do all right, but the hurricane just caused more issues for the one-third of the crop that is ridden with disease and insect damage.”
Weather Favored LCB, White Mold
As expected in the hot, dry conditions, lesser cornstalk borer posed a particular challenge, and the lack of rainfall rendered treatments ineffectual. Lack of rainfall also meant fungicides were not as effective on white mold, another problem in the given weather conditions.
“Very warm temperatures this season fueled white mold; dry conditions drove it underground,” says Bob Kemerait, University of Georgia Extension plant pathologist. It was only at harvest that many growers became aware of how serious the problems were in their fields.
White mold is often the No. 1 cause of the loss of peanuts due to disease in a season, according to Kemerait. Sclerotium rolfsii, the causal agent of white mold, is a fungus that remains in the soil between cropping systems. It waits for the next susceptible crop to be planted, and shortened crop rotations, a result of deflated commodity prices and a lack of alternative row-crop options, are a contributing factor.
Short Rotation Effect
“White mold has been really bad this year for a couple of reasons: I think we’re on a shorter rotation because we’ve got big peanut acreage behind big peanut acreage. The second thing is [that] conditions are favorable; very hot weather fuels the disease, as does very dry weather. When you have a double-edged sword — hot and dry weather — what happens is that the heat fuels the white mold and the dryness pushes it underground. It then gets harder to hit with a fungicide,” he says.
Kemerait was urging producers to be very aggressive with disease management until the very end and to use the most effective products available with the proper timing and correct water volume. In a dry year with little to no rainfall to move fungicides down into the crown of the plant, it was even more important to use the water volume and spray timing to get the fungicide down the peanut plant past the leaves and limbs to the crown and pegs along the soil line.
Both the quantity and quality of this year’s crop remains to be seen until harvest is complete, but drought conditions were sure to have impacted both in Georgia.
Portions of this article provided by University of Georgia College of Agricultural and Environmental Sciences.