What is in this article?:
- Fungicides finding broader use on Southern crops
- Blight has gotten early start
• Anyone who grows peanuts knows the need for fungicides.
• But in recent years, Southern farmers have increasingly used fungicides on corn, cotton and soybeans, and it is working for them.
Blight has gotten early start
With the cool, wet start to planting this year, Kemerait says, Northern corn leaf blight showed up in early May, the earliest it has ever appeared in Georgia, setting the stage for a well-timed fungicide application in corn. Leaf blight variety trials will be spotlighted at this year’s field day.
And where rust is a problem, he says, a single fungicide application on corn can easily bring an increase in yield of 10 bushels per acre; even more for soybeans. “I think in corn and soybeans, our growers have reached the stage where they are very comfortable using fungicides to make them money,” Kemerait says.
Where growers may not be comfortable using fungicides, though, is in their cotton fields. But that’s changing with the increase in pressure from a disease called cotton target spot caused by Corynespora cassiicola.
“Using fungicides on cotton has kind of come out of left field. But for an increasing number of growers across the Southeast, the use of fungicides to manage target spot is of considerable interest now, but is also approached with uncertainty and a healthy dose of caution,” Kemerait says.
Last year, he says, cotton target spot stretched from Alabama to Virginia, and growers saw advantages to using fungicides in battling it in severe situations, noting that the disease can fast defoliate cotton when it hits early in a season. Fungicides can save up to 200 pounds of lint per acre.
Target spot, he admitted, can help cotton at certain times. A little defoliation late in the season can actually help prevent boll rot in rank-growth cotton, which is most often hit by the disease.
Kemerait is now introducing a risk management tool for cotton target spot to help growers weigh their options on if, when and how to apply fungicide to control it.
“Growers should scout their fields at the approach of first bloom to determine if target spot is present. From research conducted in Georgia, the optimum timing for an initial fungicide application is sometime between the first and third week of bloom. An additional fungicide application may be needed approximately three weeks after the first application,” he says.
With increase in fungicide use to protect crops, there is the risk, or a big concern, Kemerait said, for fungicide resistance, something that can and does happen. “Using more fungicides on corn and soybeans can really put some pressure on resistance happening with our triazole- or strobilurine-based products. We don’t want that. … We’ll have to be careful.”
(For additional information about the Sunbelt Expo Field Day and Sunbelt Expo, visit http://sunbeltexpo.com/).