What is in this article?:
- Cotton root rot is a devastating disease that costs farmers thousands of dollars every year.
- After testing several fungicides through subsurface drip irrigation injection for several years, specialists discovered that flutriafol, a fungicide labeled only for soybeans and apples, will control the fungus that causes root rot.
This year they tested a liquid formulation applied at planting in the furrow with a seed firmer (used similar to a pop-up fertilizer application). “We can mix flutriafol with water and put it right into the seed bed, before the seed is covered,” Minzenmayer says. “That technique looks good even at lower rates.”
They say the at-planting, liquid treatment offers farmers who use drip, pivot or flood irrigation, as well as dryland producers, an opportunity to apply the material.
They’ve tested a stem drench, spraying the material at the base of the plant in-season. “We’ve run trials with pivot irrigation and flood irrigation,” Drake says. “We got a response with the pivot, but not flood irrigation.” Isakeit observed disease reduction with stem drenches in dryland cotton in Blacklands and Upper Coast trials. An early timing, weeks before the appearance of disease, was critical for effectiveness. However, this approach is probably not feasible for most growers.
Variable Rate Application technology may play a role, as well. Using infrared imagery or other technology to identify and map root rot hot spots, farmers may be able to apply material just where it’s needed, not to an entire field.
The one drawback to that possibility may be the inconsistency of the disease. “Infection is sometimes hit-or-miss,” Drake says. “We can’t always be sure it will show up in the same place the next year. It’s a fungal disease so it needs to have a susceptible plant and the proper environmental conditions to develop.”
He says it often starts in a circle and moves outward, but plants within the circle are often missed.
Minzenmayer says finding an effective product represents a significant achievement in managing root rot. But they need to refine rates and application techniques before it’s ready for widespread use. “In 2011 we will fine-tune rates and find an effective range.”
Drake says farmers will come up with new ideas on how to apply the material once it’s approved. In the meantime, he recommends patience.
“When we get it labeled, we can refine the delivery method.”