Don’t let your guard down. That’s the lesson this year for peanut producers who are feeling fortunate that their levels of tomato spotted wilt virus have been relatively low in recent years.
“Although 2006, 2007 and 2008 were low years for tomato spotted wilt virus, I tell growers that if they start to think it’s no longer a problem, then you’ll have a problem,” says Bob Kemerait, University of Georgia Extension plant pathologist.
As is their usual practice, specialists and researchers from the University of Georgia, Auburn University and the University of Florida gathered this past December to reassess the Peanut Risk Index and make any changes they felt were necessary based on data and field observations from the 2008 production season.
In 2005, the Spotted Wilt Index and the Peanut Fungal Disease Risk Index were combined to form the Peanut Disease Risk Index for peanut producers in the Southeastern United States. The Peanut Disease Risk Index, developed by researchers and Extension specialists in Florida, Georgia and Alabama, is now officially known as Peanut Rx.
“Basically, the only thing that has changed as far as the index or the points for 2009 has been the variety section,” says Kemerait. “We dropped some varieties that weren’t going to be planted anymore and aren’t readily available. We also added up-and-coming varieties for which we have data. We adjusted some of the points slightly to be more in line with what we see the risk being. One in particular is GA-06G. It’s more resistant to some of the diseases than we initially gave it credit for — we dropped some of those values, so it’s fewer risk points.”
All other categories remain the same as in 2008, says Kemerait.
Syngenta Crop Protection and Nichino will continue to support prescription programs for fields determined to be at low, moderate or high risk according to Peanut Rx, he says. “Peanut Rx is gaining importance not only as an educational tool for helping growers minimize risk in their fields, but also as a tool for chemical companies to match a grower’s risk to what they recommend growers use on their farm,” he says.
This past year, it was estimated that peanut producers’ yield losses due to tomato spotted wilt virus was about 1 percent in the lower Southeast, says Kemerait. “It was about as low as it has been since we started keeping records on the disease in 1990. Part of this has to do that it was a relatively light year for the virus. But it always has to do with resistant varieties and the management of this disease by growers,” he says.