What is in this article?:
• The Peanut Rx is a risk index that helps Southeastern growers make smarter disease management decisions.
UNIVERSITY OF GEORGIA Extension plant pathologist Bob Kemerait, left, discusses peanut fungicide programs with a grower during the recent Georgia Peanut Farm Show held in Tifton.
A package you can use
“What’s the difference in resistance to white mold between Georgia-07W and Georgia-06G? This program helps you put this information into an overall package you can use.”
Factors considered by Peanut Rx include variety, crop rotation, planting date, final plant stand, tillage, irrigation, field history and insecticides.
“With Peanut Rx, we can go in and assign a total risk of leafspot, white mold and TSWV, and the supporting companies can offer a specific program. The value of a specific program is that you’re putting out the right amount of fungicide where you need it, and you’re spending the right amount of money.”
Peanut Rx changes every year and gets better, says Kemerait.
“We get new varieties, new data, and sometimes we get a new fungicide. Our index continues to evolve. We no longer include limb rot in the index because it hasn’t been a big enough problem over the past 10 years that we can get good data. If we can’t get good numbers, we don’t put a disease in the index.”
The more points assigned by the index, the greater the risk. A variety with 50 points is much more susceptible than a variety with five points. All factors contribute to risk, but the most important are how long it has been since you’ve had peanuts in the field, what variety you are planting, when you planted, and what kind of plant stand you ended up with. The other factors have an impact but not as great as these, says Kemerait.
“After total risk points are determined for a field, the next step it to break the point totals into low-risk, medium-risk and high-risk fields.
“Low-risk means you’ve probably been out of peanuts for awhile, you’ve got a good resistant variety, you’ve got good rotation, tillage practices that work, and your planting date is right. If you’re high-risk, you’re planting peanuts behind peanuts or every other year, and you’ve got a weaker variety as far as resistance goes.
“You don’t need the same amount of fungicides in a low-risk field as in a high-risk field, but growers tend to spray it the same. Why would growers spray a field seven times when four or five sprays are sufficient in reduced-risk fields?
“The first reason is that it’s easier to remember what you’re going to spray and it takes less time to think about it. The other reason is that you’ve got a lot confidence in the fungicide programs you have always used.