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N.C. Peanut Farmers: Look Out for Leaf Spot in 2019

N.C. Peanut Farmers: Look Out for Leaf Spot in 2019
By Ryan Adams
 
Leaf spot remains the No. 1 disease worry for North Carolina peanut farmers, and North Carolina State University Extension Plant Pathologist Dr. Barbara Shew is urging folks to be prepared this year. 
 
“We’ve been in a situation for the last couple of years where everything has been very favorable for diseases to develop. Long periods of high relative humidity are very favorable for leaf spot development. Temperatures from 60 to 90 degrees are favorable for leaf spot,” Shew said at an Extension peanut production meeting in Williamston.
 
“We can have periods of high relative humidity even during dry spells. For the past couple of years, we continued to have high humidity and warm over-nights even at times when it was not raining. This is favorable for leaf spot,” she added. 
 
For several years now, favorable conditions for leaf spot began early and remained well into the fall with spray dates right up to Sept. 30 throughout North Carolina. “If you put the cycle of leaf spot starting earlier in the year and lasting later, we’ve ended up with a lot of extra time for leaf spot to develop,” Shew explained. 
 
In addition, because of humid conditions and hurricanes, big populations of leaf spot pathogens have been building up statewide. “Because of hurricanes and late digging and pod loss and in some cases, fields being abandoned, we’ve had a lot of volunteers out there, and volunteers are an excellent way to keep the pathogen surviving over a longer period of time than you would have otherwise,” Shew said.