Rotation, Peanut Rx and fungicides are a good way to start planning for disease in 2022.
Hosted by Alabama Cooperative Extension, University of Florida/ Institute of Food and Agriculture Sciences Extension and the University of Georgia Cooperative Extension, the tri-state peanut disease tour was a chance to see the latest technology available to protect peanuts from both foliar and soilborne pathogens. Attendees learned about plot trials and about the year’s top disease problems in growers’ fields.
The UF portion of the tour was presented virtually. At that time, peanuts had been planted in the small-plot trials about 100 days ago. The plots were in 30-inch rows and were 30 feet long.
UF Extension disease specialist Nick Dufault says they have been doing trials for six years at the North Florida Research and Education Center in Live Oak.
“For most of that time, we had the trial in the same field. This year, we moved it to a field that was in corn for the past three years. We are just now starting to see peanut disease.
“Typically, we would have significant leaf spot pressure at 50 to 70 days after planting. It would ramp up to where we had nearly complete defoliation and just sticks by the end of the season,” he says.
It was a visual representation of how important rotation is in disease management, Dufault says.
Additionally, he says they have found that using Peanut Rx as a guide is a good way to keep disease pressure to a minimum compared to chlorothalonil only.
Key points from research and Extension on soilborne disease and nematodes are:
→ Tools to fight white mold. The best way to prevent white mold is to be on a good crop rotation and have a solid fungicide spray program. Be mindful when scouting fields that white mold can show few above-ground signs. It is important to dig up plants to fully assess what is going on with the crop during the season.
→ Rhizoctonia. It was a wet season in many areas, with cooler temperatures that brought more Rhizoctonia pressure. This fungus can severely affect the limb crop in peanuts and result in reduced yields. Seed treatments, crop rotation and good fungicide spray programs can help with less-than-ideal planting and growing conditions to limit Rhizoctonia pressure.
→ Root-knot and lesion nematodes. Consider sending soil samples to a diagnostic lab at least every few years to evaluate nematode pressure across your acres. Effective diagnosis of nematodes takes more than a visual inspection. Ideally, sample the top 8 inches of soil with a probe, and label each sample. Early fall is the best time to sample for nematodes.
Hunt Sanders, field market development specialist at Valent U.S.A., attended the tour as well.
“These pressures aren’t unique to 2021. I expect we’ll continue to see white mold, Rhizoctonia and nematodes as part of planting conversations in 2022,” he says. “Looking ahead with fungicide plans is a solid step. There are a lot of resources out there when it comes to planning, including Peanut Rx, which accounts for variety, timing, tillage, rotation, disease pressure and more.
“For disease management, I continue to recommend Excalia fungicide for fields facing white mold, Rhizoctonia, Sclerotinia blight and leaf spot.”