By Jim Steadman
As new issues arise in cotton fields from year to year, scientists continue to look for solutions to keep these problems at bay. Some of those solutions often come from unexpected sources. And, some may even bring additional benefits to the field.
When it comes to managing target spot and herbicide-resistant Palmer amaranth, two new potential options may provide additional firepower to existing management programs.
A Moving Target
Quadris fungicide has been labeled for use in cotton for a number of years. And with the increasing incidence of target spot, especially in Southeastern fields, it has become an effective line of defense against the disease. But in-field studies have also shown possible plant health benefits that help young cotton plants grow stronger, healthier and more vigorously, leading to potential yield bumps at harvest.
“In the cotton market, the number of fungicide applications have increased dramatically in the last few years,” reported Wilson Faircloth, agronomic service representative for Syngenta. “We know Quadris is a very good product for foliar control of target spot and other diseases, and we’re actively pursuing that. But we’re also looking at some of the crop enhancement benefits we have noted in other crops from early applications.”
During 2012, Syngenta, in cooperation with university researchers and consultants from the Carolinas to Texas, conducted on-farm studies to determine the extent of crop health benefits from early season application of Quadris. Tests were conducted on both dryland and irrigated sites.
“We put it out at a six ounce rate early post emergence,” explained Faircloth. “That’s around the two-to-four leaf stage, when growers may be considering an early post herbicide application or thrips cover spray. Because Quadris is systemic in the plant, getting it on earlier also gets it into the plant to a greater degree.”
In most locations, plants showed greater vigor and height earlier in the season, often with more nodes per plant. That could be a plus for growers, especially those considering earlier planting dates, since healthier plants are usually more resilient to other stresses such as thrips pressure or weather-related issues. And, treated cotton showed an average of 50 additional pounds of lint per acre at harvest across all study sites.
Syngenta plans to continue the field studies with universities and consultants in 2013. “We always need more data,” stated Faircloth, “but we feel very confident that growers will see a return on investment for doing this.”
New Use for an Old Residual
In the battle to manage Palmer amaranth, researchers and growers alike have reached into the proverbial toolbox for reliable, tried-and-true herbicides, as well as a bit more steel. So it shouldn’t come as a surprise that some studies conducted in 2012 reached way back to see if a herbicide compound from the late 1970s and early 1980s might have a fit in the pigweed wars.
Fluridone, a bleaching herbicide that was originally evaluated in cotton more than three decades ago, was studied in 2012 for extended residual control of Palmer amaranth. The research was a cooperative effort between Cotton Incorporated, the National Cotton Council and SePRO Corporation, manufacturer of the product, known under the brand name Brake.
Fluridone is currently labeled for aquatic weed control under the name Sonar.
When originally evaluated in cotton, fluridone proved to be a broad-spectrum preemergence herbicide with good cotton tolerance and good residual control at relatively low use rates. The 2012 trials were conducted to help determine use rates targeting Palmer amaranth and to evaluate integrated weed management programs using Brake as a base residual herbicide.
Preliminary results indicated that preemergence applications of Brake effectively controlled Palmer amaranth up to eight weeks when there was sufficient moisture for activation. Any escapes occurred before activation or in drought conditions.
Tyler Koschnick with SePRO reports Brake will remain in broad scale field evaluation in 2013, with some Section 18 labeling possible.