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.
New options needed
In the past, farmers with root rot infections had only one option—rotation. Drake says wheat and grain sorghum are possibilities. “But we’ve seen fields following two years of wheat with terrible root rot.”
No varietal resistance exists. “Rotation or some kind of chemical are our only options,” Drake says. “Old literature suggested adding manure or other organic matter and deep plowing, but those options are not viable for most growers. Root rot remains a devastating disease.”
“Root rot is a significant economic factor throughout the Southern Rolling Plains,” Minzenmayer says. “I fully realize the effect it has on farmers after harvesting plots this fall. Dead stalks break off and go into the stripper where they either get crushed and pushed into the basket and cause quality problems or they clog up the machinery.”
He says farmers with heavy root rot infestations often have to climb off strippers every few feet to unclog the machinery. “I’ve seen fields with 3-bale yield potential that have stretches of 30 to 40 feet with nothing on the stalks.”
He says farmers are taking significant hits on yield and grade.
Minzenmayer, Isakeit and Drake hope further testing of flutriafol will provide management options. “We know it works,” Drake says. “We have to refine application techniques and rates.”
They initially concentrated on injecting the material through drip irrigation tape on the Wilde farm. That research showed that applying the material directly under the row instead of in the middles (where some irrigation tape is located) works best since the material does not appear to move.
They’ve also looked at adding the product to liquid fertilizer and applying with a fertilization rig. “It did not combine well with the liquid fertilizer,” Drake says.
They tried treating seed but found they could not get enough concentration on the seed to be effective. Applying the product on corncob granules at planting seemed to work, “but the company does not want to develop a granular formulation at this time,” Drake says.
They tried to knife in the material during the growing season and got no response.