Farmers are always looking for an “edge;” i.e., a way to increase yields or improve quality without breaking the bank. But they don't always know who came up with the latest new technology that helped them harvest more bushels of grain or pounds of lint.
Sunbelt growers who increase their yield and lint quality with applications of a foliar fungicide on cotton during the 2008 growing season can be thankful that Greg Stapleton was in the right place at the right time.
When Stapleton, BASF's technical service representative for the upper Mid-South, began working with applications of the company's pyraclostrobin or Headline fungicide on corn and soybeans in the early 2000s, a light bulb went on.
“I was working on some plots at the Agricenter,” said Stapleton, referring to the complex located on the former Shelby County Penal Farm property in east Memphis. (The land in the Wolf River bottoms near the Agricenter is used by a number of farm input suppliers for testing new products.)
“We had first looked at Headline — one of the Strobilurin fungicides — on wheat and then on fruits and vegetables, peanuts and then corn and soybeans,” said Stapleton. “So I started thinking why not cotton?”
Stapleton had been working with Stoneville Pedigreed Seed Co. on four cotton plots that were coming up on mid-bloom. So he sprayed a portion of them with Headline and monitored them through the remainder of the growing season.
Although foliar fungicides have been used sparingly in cotton — most fungicides have been applied as seed treatments or in-furrow, Stapleton saw enough improvement in yield and quality to know he was on to something.
“What started on four plots went to four states,” he said. “We sprayed Headline on five varieties at six locations in Tennessee, Arkansas, Mississippi and Louisiana and harvested from 50 to 300 pounds more lint in the treated plots.”
BASF, meanwhile, began seeking a federal label for the application of Headline fungicide on cotton. With that registration pending in 2007, researchers were able to expand their testing from research plots to commercial fields.
“When we got on some farms, that's when the differences really started showing up,” said Stapleton, who is based in Dyersburg, Tenn. “The information gleaned from the 2007 field tests told the story.”
Foliar diseases are not a new issue in cotton. Scientists have known for years that growers sometimes lose yield to Alternaria, Anthracnose, Ascochyta blight, Cercospora, Diplodia, Fusarium species, Phoma blight, Puccinia, Phykopsora and Stemphyllium diseases (boll rot, hard lock, blights, rust and leaf spot).
But producers seemingly had so many other problems to deal with they didn't place much emphasis on treating cotton with foliar fungicides. At least not until tests with Headline produced yield increases of 50 to 300 pounds of lint per acre.
One of the most impressive demonstrations of the effectiveness of a foliar fungicide occurred at the Judd Hill Farm Field Day that is held annually just outside Trumann, Ark. Cotton treated with Headline to control high infestations of Alternaria leaf spot yielded 194.4 pounds more lint per acre than untreated cotton.
In a Georgia cotton fungicide study, Headline controlled Ascochyta “wet weather blight” that caused 90 percent defoliation in untreated cotton. Cotton sprayed with Headline had less than 10 percent defoliation due to the disease.
“We've been finding in some locations that we also had 3 percent better gin turnout where Headline was applied,” said Stapleton. “We believe Headline allowed the leaves on the plants to stay healthier longer. So more energy went into boll production and filling out the bolls.”
Researchers are recommending that farmers apply 6 ounces of Headline at first bloom plus 10 to 14 days on early to mid-maturity cotton varieties. On later-maturing varieties, the recommendation is first bloom plus 14 to 28 days.
Growers can make additional applications of 6 to 12 ounces — up to a total of 36 ounces per season. To limit the potential for development of resistance, BASF is advising growers to make no more than two sequential applications and then rotate to another chemistry.
Headline can be applied with insecticides, other fungicides or BASF's Pentia plant growth regulator. For aerial applications to cotton, use a minimum of 5 gallons of water per acre and for ground, a minimum of 15 gallons per acre. Growers should use a recommended adjuvant with applications of Headline.