North Carolina peanut crop diseases wet weather 2013

PLANT BREEDER Tom Isleib, right, says Bailey and Sugg varieties released by his program seem to have weathered the excessive rainfall well this summer.

Bailey, Sugg peanut varieties held off diseases during wet summer

• The high percentage of Bailey (estimated at 50 percent of the North Carolina crop) and Sugg (25 percent of the crop) planted, significantly reduced the amount of damage to peanut yield caused by diseases.

Heavy rainfall, along with long stretches of cool, cloudy weather, left a non-uniform maturing peanut crop that will need some special attention.

Peanuts look promising and most contend samples show a good crop, but until the peanuts are dug, picked and run through the scales no one will really know how much damage this year’s crop suffered from standing in water through much of June and July.

“That’s the big unknown — what effect did standing in water for so long have on what’s below the surface.

“If you look at peanuts across North Carolina, they look good, but the effect of the rainfall is a big unknown,” says North Carolina State Peanut Specialist David Jordan.

“I think we will have a good crop this year. I’m guessing, and it’s mostly a guess, that growers will end up producing 3,500-3,600 pounds per acre, Jordan adds.

That estimate may actually be low, he says. “There will be lots of soggy peanuts that will lose yield, but exactly how much yield we will lose and what we end up with will depend a great deal on what kind of weather we get throughout the harvest season,” he adds.

North Carolina State University Plant Pathologist Barbara Shew says the record rainfall likely contributed to a number of ‘mystery diseases’ that came through her lab this year.

“I’ve gotten several plant samples with disease symptoms that look a little bit like one thing, a bit like another disease, and it’s hard to know whether the excessive rainfall masked the symptoms of one disease or created new symptoms from commonly occurring diseases,” she says.

“I think some of the yellowing and other disease problems that growers are seeing are mostly physiological symptom caused by weather related issues. “However, I’m paying special attention to all these mystery diseases, because we have to be sure we are not dealing with something new that growers will see in future years, when weather isn’t so much of an issue,” she adds.

Bailey, Sugg varieties saved the day

For sure, the high percentage of Bailey (estimated at 50 percent of the North Carolina crop) and Sugg (25 percent of the crop) planted, significantly reduced the amount of damage to peanut yield caused by diseases.

For much of the year conditions were ideal for diseases to flourish, yet for the most part Bailey, in particular, seemed to literally weather the storm much better than other varieties.

Tom Isleib, North Crolina plant breeder and head of the program that released Bailey, then Sugg a few years back, says he is confident Bailey will stand up to intense disease pressure during normal growing seasons.

This year was far from normal, but these new varieties seemed to hold up well under climatic conditions that exceeded any conditions under which the varieties were tested prior to their release.

Shew says tests across North Carolina showed the heavy disease pressure took a heavy toll on other varieties. “We saw some disease damage on Bailey and Sugg, but nothing like what we saw on Champs and some of the other varieties,” she adds.

Regardless of what variety is planted, taking care of disease issues the last few weeks prior to harvest will be accentuated this year.

What many are calling a 100 year rain occurrence has left a very non-uniform peanut crop in the Upper Southeast this year.

Even peanuts that were planted on time were slowed by the rain, but more so by long periods of cool, cloudy weather.

Other peanuts were planted late, some as late as July. The combined result is that harvest season will be spread out longer this year to account for the lack uniformity.

This year digging began in mid-September and will likely last until first frost — or beyond.

Shew notes that peanut fungicide application typically begins at about the R3 growth stage and lasts until the first week or so in September. On that schedule growers will apply fungicides five times. Perhaps with Bailey and Sugg growers can cut out one fungicide application, she notes.

This year many peanut fields will be in the ground longer than normal, because of the unusual weather. If the weather cools down in late September and October, it will put the brakes on leafspot, but it will also further delay the peanut crop.

This year is tricky for growers, because the season is stretched out. In many fields it’s likely, regardless of what variety is grown, that some will need an extra fungicide application to protect their crop until digging time.

“If we get a hurricane or tropical storm late in the extended growing season, then all bets are off, because growers may not be able to get in their field for 10-12 days and fungicide applications last only about two weeks.

Extra fungicide application

“If we do get one of these tropical fronts, then almost certainly an extra fungicide application will be needed,” Shew says.

“For the last fungicide application, Bravo is the best fungicide to use. It is a broad spectrum fungicide and more likely to kill fungi that might have resistance to some of the other fungicides used and prevent this leftover disease fungi from being carried over to next year’s crop.

“An exception to using Bravo as the last fungicide application is when growers have sclerotinia in a peanut field.

“Bravo will likely make sclerotinia worse, if we get cool, wet weather between now (mid-September) and digging.

“One alternative to Bravo as the last fungicide application is Fontellis.

“In our trials one pint of Fontellis — at the recommended rate for leafspot — did not provide much control on sclerotinia. If we went up 1.5 pints per acre, the labeled rate for sclerotinia is equal to the one pint per acre rate of Omega in fields with heavy disease pressure,” Shew says.

“Omega must be applied 30 days prior to harvest, which may be an issue on some of these late planted peanuts,” she adds.

“It’s always a good idea to use a high rate of water, usually 20 gallons per acre, to insure getting enough of the fungicide down into the foliage of the peanut plant to control diseases.

“In these late season applications it may be helpful to spray early in the morning or at night to insure adequate coverage,” Shew says.

This year, more so than any in recent history, will demand that growers be highly accurate on when to dig peanuts.  A lingering problem from all the rain is a heavy crust of soil that has left many peanut fields hard, as hot, dry weather came in September and literally baked the moist soil.

Getting peanuts to full maturity will be critical to keeping pods on the stem during the digging process. In large part, how well growers time digging and how efficiently they dig their peanuts will likely make the difference between an average and a good crop.

[email protected]

          More from Southeast Farm Press

Unmanned aerial vehicles have bright future in precision farming

Photos: A day on the 2013 Georgia Peanut Tour

As grain prices fall, growers need to develop crop budgets for 2014

Pre-conditioned calves in high demand







Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.