It's important to scout fields for this disease before first bloom, he said. Look for it in fields back to back in cotton, fields with a history for the disease and fields with conservation tillage practice in it. Spores can survive in the residue and splash back up to young plants. Irrigated fields and high-yielding, rank-growth cotton varieties are suspected to be at risk for the disease, he said.
Positive identification is the first step in managing this disease. One challenge for growers is that positive disease identification requires a laboratory test. But, as growers well know, assumptions and fungicide applications are expensive relative to the minimal costs to have a leaf spot properly identified.
"The bottom line is that there are no clear guidelines for control of foliar diseases in cotton," said PhytoGen cotton development specialist Russell Nuti. "We are working together to develop a better understanding of how to best manage them."
"How important it's going to be in year-to-year management, whether it's going to be an issue every year, are questions still to be answered," said PhytoGen cotton development specialist Steve Brown.
Kemerait, along with Auburn University pathologist Austin Hagan, plan to build a risk index for growers to use to gauge and manage their field's risk for the disease. It should be available in early 2013.
"What we do in land-grant research and extension is try to take the speculation out, especially in a new disease like this one. We wouldn't be doing our jobs if we didn't take this seriously and find ways to help growers manage it," Kemerait said.