What is in this article?:
- Great strides have been made in peanut disease control in recent years, especially through the development of genetically improved varieties.
- But as producers look ahead to the 2012 production season, white mold looms large as a serious disease threat.
Control begins with rotation
Generally speaking, the management of white mold begins with rotation, says Kemerait.
“The best way to reduce the inoculum buildup of white mold is to rotate away from peanuts and soybeans and other susceptible crops and deep turn the soil. Sclerotia (fungal “seeds”) of the white mold fungus will survive for several years in the top inch of soil where oxygen is plentiful. If you bury the sclerotia, they survive for about one year.”
It’s also important, says Kemerait, to choose an appropriate fungicide program for controlling white mold.
“Every grower will consider using tebuconazole this year. It’s cheap, and it’s a good fungicide. But don’t use it just because it’s cheap — make your fungicide choice based on the pressure in your field and your needs. The newer fungicides coming out have efficacy towards white mold that surpasses what you’d normally expect from tebucoanzole.”
It’s important, says Kemerait, that growers apply fungicides at the appropriate time.
“Initiating a white mold program at 60 days after planting has been our general recommendation for years. But knowing that white mold can come in earlier in a warm year, and you know you have the option of cheap applications of tebuconazole, you might consider starting your fungicide program a little early, while keeping your standard program white mold program intact later in the season.
“Another option might be to simply start your standard program earlier than normal, for example 45-50 days after planting and then extending it with additional applications of an appropriate fungicide.”
Research also has shown the benefits of applying fungicides at night or early in the morning. The biggest challenge of managing white mold is getting the fungicide to the target, says Kemerait, and by spraying at night, you have a clear path to the target.
“Spraying at night allows us to get the fungicide where we need it, and we don’t have to deal with a heavy canopy.
“We recommend irrigating after applying a fungicide or spraying ahead of a rain event because we need some vehicle to move the fungicide down.
“Spraying at night gets it to where it needs to be. It improves your white mold control in a bad situation.”
In 1994, the game changed for peanut white mold control, he says, with the introduction of Folicur. It was followed in 1995 by Abound. Now, there are several options in terms of fungicides for controlling the disease.
“We get the best performance from these fungicides through rotation, selecting a resistant variety, and, regardless of the fungicide program you choose, making sure you stay on time and ahead of disease.”
New fungicides are available, says Kemerait, including Fontelis from DuPont that received registration this year and has shown excellent control of white mold.
Research has shown, he says, that the impact of a white mold control program can begin two to three weeks after the plant comes up.
“Sixty days has been the historical timing to begin a soilborne fungicide program, but early season fungicide applications can be very important.
“We can do this by banding a full 5.7-ounce broadcast rate of Proline from Bayer Cropscience over the row at early emergence. Early emergence refers to a fungicide application between two and five weeks after planting. Timing of applications and the fungicide you choose go a long way in managing white mold.”