For all those growers who have ever sat down and scratched their heads over how much mepiquat chloride they should apply on their cotton, there's a new product that may help simplify that decision.
Mepiquat-based applications can be put out in a dizzying array of combinations — 4 ounces followed by 8 ounces followed by 12 ounces or 8 ounces followed by 12 ounces or 12 ounces followed by 8 ounces, etc.
“With Stance SC Plant Regulator, it's either 2 ounces or 3 ounces,” says Donny Oleniczak, product manager for Bayer CropScience. “If the plant has medium vegetative vigor, you will probably apply 2 ounces; with high vegetative vigor, you would be more likely to apply 3 ounces.”
Stance, which contains the active ingredient cyclanilide, is the first significant innovation in the plant regulator market in 25 years, according to Bayer CropScience. The company received a Section 3 EPA registration for Stance last August and is awaiting California EPA approval.
Cyclanilide inhibits auxin transport and gibberellic acid synthesis. Both are major hormones that regulate the growth of the cotton plant.
“When Stance is applied to cotton, its dual mode of action on the growth hormones auxin and gibberellic acid are optimized at low rates and in a narrow rate range,” said Oleniczak. “Once you find the right rate, more is not better.”
He said the outcome of inhibiting the hormone auxin in a cotton plant is dependent on the growth stage. Early-season applications of cyclanilide inhibit cell elongation without affecting cell division. Interference with auxin hormones produces different effects depending on the growth stage of the cotton.
The simplified use rates for Stance are drawn from university trials in 15 states and discussions with consultants that indicate the 2-ounce rate is best for moderate conditions and the 3-ounce better for aggressive conditions.
“Our experience in university trials is that these standard rates are quite effective, Oleniczak notes. “Your experiences may cause you to establish a slightly different rate, but on your farm, you can expect to have a standard rate.”
That's in contrast to rates that can vary by as much as 4 to 24 ounces for mepiquat chloride-based products, according to the company.
“Although most people have their own standard recipe with mepiquat chloride, there's no standard usage,” says Craig Bednarz, University of Georgia Extension cotton specialist who spoke on early cotton development at the Beltwide Cotton Conference in San Antonio. “With Stance, we knew the direction we wanted to go. The focus has always been on capitalizing on a simpler plant regulator program.”
Bayer CropScience recommends that growers begin applying Stance when 50 percent or more of the cotton plants have reached the matchhead-square stage. Growers should begin sequential applications seven to 14 days later based on growth and environmental conditions.
“If you're growing a standard variety under normal weather conditions, you might apply 2 ounces, 2 ounces and 2 ounces,” says Oleniczak. “If you're growing a variety like DP 555 BG/RR under irrigation, you would probably apply 3 ounces, 3 ounces and 3 ounces.
“In university tests in 2005, we were able to stay in there with applications of Stance at 3, 3 and 3 ounces followed by 3, 3 and 3 ounces vs. mepiquat chloride at 4, 8, 12, 14, 16 and 16 ounces. We were able to match up with height performance and yield performance.”
“This was the only gap we had in our product portfolio,” says Scott Johnson, cotton product manager for Bayer Crop Science. “And we think Stance will fill that spot nicely.”