Saturday, June 15, 2024

Season Update

More frequent and heavier rainfall leads to more Valor injury and earlier disease pressure.

⋅ BY AMANDA HUBER ⋅

Rain is a necessary element to peanut production. “If it don’t rain, it don’t matter,” was a favorite mantra of the now-retired University of Georgia Extension peanut specialist John Baldwin. Even so, there are issues caused by rain that producers should be ready for. Whether it is the onset of disease because of increased spore dispersal or herbicide injury to seedlings, awareness of these potential problems is the first step to mitigating the harmful effects.

Be Ready For Fungicide Applications

Bob Kemerait, University of Georgia Extension plant pathologist, says if it continues to rain into late May and early June, conditions will be more favorable for diseases like leaf spot.

“The rain action, the mechanical splashing on seedlings, actually aids in disease spore dispersal,” he says. “If we stay in the weather pattern we’re in now, which is a little more rainy, it is probably best to start a leaf spot program earlier than later.

“Coming into a period with increased rain activity, don’t delay in getting started on your fungicide applications.”

Another factor to watch out for is the higher temperatures.

“If we continue to have increased moisture but also higher temperatures, that could set off an early white mold epidemic,” Kemerait says. “Pay attention to the weather, temperature and rainfall. Start with fungicides as on time as possible.”

Fungicides that can be used at 30 days after planting include tebuconazole, Elatus or Excalia, he says. “Lucento and Priaxor also have some white mold activity to get started early.”

Yield Is Not Often Affected By Valor Injury

UGA Extension weed specialist Eric Prostko says 99% of the time peanuts recover from Valor injury without yield loss.

Wade Parker, UGA Extension Southeast district area agronomist, says the East Georgia area was quite wet midway through planting.

“The first few weeks of planting were dry, but as of the last few days, we got an inch and a half to two inches of rain and even a report of 2.25 inches,” he says. “Planting progress is about 40% to 45%. It’s amazing how fast these 12-row planters get things done.”

Parker says seed are germinating well, and stands look beautiful.

“This rain will likely give us Valor injury, but that is something we know they’ll grow out of. We know that we need the weed control that Valor gives,” he says.

Valor injury is absolutely expected with the rain, says UGA Extension weed specialist Eric Prostko.

“What 27 years of research on this product has shown us is that 99% of the time peanuts recover without yield loss,” he says. “Injury is going to happen with this amount of rain, especially in fields where peanuts were just coming out of the ground.”

An Early Post Herbicide Recommendation

Prostko says growers who have missed the recommended application timing for applying Valor, Strongarm and Prowl or Sonalan preemergence should not panic.

“My suggestion would be to let the peanuts emerge, then treat herbicide ‘naked’ fields with an early post application of Gramoxone plus Storm or Basagran, with Zidua or Anthem Flex and a non-ionic surfactant, a recommendation that can be found on page 221 of 2024 UGA Pest Control Handbook.”

Prostko says he usually does not have a preference between the Group 15 herbicides (Anthem Flex, Dual Magnum, Outlook, Warrant, Zidua).

“However, in fields that were not treated with any Prowl or Sonalan, I do prefer Anthem Flex or Zidua as the first early post treatment because these herbicides provide slightly better control of Texas panicum, also called bullgrass or buffalograss.”

In trials with no preemergence herbicides, Prostko says he has been able to obtain very effective weed control with the early post recommendation, thought it may not be ideal.

Prostko offers one last reminder about rains. “Depending on timing, at some point that peanut may be flat on the ground laying in whatever is in the water around it, whether it is herbicides or disease spores. Just keep that in mind.” PG

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