What is in this article?:
- Early-season disease control keeps peanut yield foe at bay
- Takes bigger yield now
- CBR has been minor problem
- Early emergence banding
• The old yield-robbing foe that has popped up with too much regularity from Georgia to Mississippi over the past three years is white mold.
• Caused by the fungi Sclerotium rolfsii, white mold, or Southern stem rot, as it is often called, came on late in the season and kept statewide yields across the belt from setting the record yield bar even higher.
UNIVERSITY OF GEORGIA Plant Pathologist Tim Brenneman explains early season peanut disease control.
CBR has been minor problem
“For the past few years, CBR, at least in Georgia, has been a minor problem. Don’t forget about CBR — it’s still around, but it’s not been nearly so much of a problem in recent years, he adds.
“Our biggest disease challenge in Georgia the past few years has been white mold. Not only are we seeing more of the disease in peanuts, but we are seeing it occur at much more damaging levels at much different times of the growing season than we used to see it.
White mold is a warm-weather craving disease. Historically, it has been considered a mid-to-late season problem, but that scenario has changed dramatically in recent years.
White mold is an historic pest of peanuts, but it’s been on the quiet side until recent years.
“The warmer early season temperatures in recent years have been particularly favorable for outbreaks of white mold, and historically white mold has been the most damaging of all peanut diseases, causing millions of dollars of loss to Georgia growers,” Brenneman says.
Currently grown cultivars are moderately to highly susceptible. Several effective fungicides are available, but they are expensive, and there are cases each year when disease control has not been as good as expected.
This occurs since Sclerotium rolfsii can grow extensively underground, and pods are a difficult target for a fungicide to reach. These fungicides are systemic but do not move down in plants.
“Night sprays, when peanut leaves are folded, and use of irrigation to wash fungicides off the foliage, have both improved disease control and yield,” he says.
Timing sprays is also important. Traditionally white mold sprays go out 60-100 days after planting. But early season hot temperatures, especially in 2010 and 2011, have allowed white mold to start much sooner on peanuts only several weeks old.
To combat this, a totally new concept in improving white mold control is the use of banded sprays early after emergence.
Back in 2010, Brenneman’s main focus was still on reducing CBR damage to peanuts.