Cotton farmers are taking “Aim” at tougher-than-normal defoliation problems using, in part, a herbicide that goes by the same name.

Growers are finding that Aim and other crop defoliants and boll openers are more and more critical if they want timely harvests without excessive trash.

From FMC Corp., Aim is already a popular herbicide for cotton and feed-grain producers. Now approved for use as a harvest aid on cotton, the product is welcome where cotton prices are low enough without added discounts at the gin. And where there's always the threat of cold, damp fall weather that can hamper harvest.

In the Midsouth, for example, last year late summer rains produced heavy morningglory outbreaks and secondary growth. Jimmie Appleberry, who farms about 2,700 acres of irrigated cotton in Tillar, located in the southeastern part of Arizona, says secondary growth was especially rampant.

“We wanted a better method of handling that type of growth,” says Appleberry. “We tried several combinations. We applied Aim tankmixed with Def (a defoliant), Aim tankmixed with Prep (an ethephon) and Aim by itself. We found that Aim by itself really knocked down the secondary growth.”

Bob Johnson, an FMC sales representative in southeastern Arkansas, says the product was applied in a “two-shot program.” Two-thirds ounce of Aim was mixed with a crop oil, followed by another two-thirds ounce and crop oil. In another combination, Aim and the oil were tankmixed with a boll opener.

The first application was made about Aug. 20, or when about 60% of the bolls were open. The second was made seven to eight days later.

“Aim is a primary cotton defoliant and can be mixed with a boll opener like Prep or Finish,” says Johnson. “It provides a bonus by killing vines like morningglory at the time.”

Sam Hill, who farms up to 1,500 acres of cotton annually, was among those who had heavy morningglory problems in late summer. “We applied Aim to get the canopy open, then FreeFall (a new defoliant) and Superboll (a boll opener),” says Hill. “That program worked extremely well.”

Randy Boman, Texas A&M extension cotton agronomist in Lubbock, says a well-managed defoliation and boll opening program can help your bottom line.

“Based on the results from a Cotton, Inc.-funded weathering project conducted in 2000, being able to harvest cotton early can mean reducing the potential for up to 8¢/lb decrease in USDA loan value,” he says. “Delayed harvest can cause many problems with ‘barky’ cotton, reduce color quality, staple length and HVI strength. This increases possible discounts for growers.”

Boman says the best time to apply defoliants is during warm, sunny weather with soil moisture fairly low. Nitrogen levels should be low, and plants should have some older leaves shed.

Conversely, applications will be hampered with temperatures below 60°, if soil is too wet, or if plants are moisture-stressed and have leathery leaves. High nitrogen levels will promote dense foliage and delayed maturity.

“Remember that harvest-aid materials cannot increase the rate of fiber development,” says Boman.

Along with Aim, other new harvest-aid products introduced recently include Cyclone Max from Syngenta, Boa and FreeFall from Griffin, Leaf-All from Luxembourg and LintPlus from Uniroyal. Other harvest-aid chemicals include Ginstar, Folex, Harvade, Dropp, Ethephon 6, Boll'd, Finish 6 and CottonQuik.