What is in this article?:
• Fungicides work primarily as a preventive.
• Once you have a disease, it’s a lot harder to manage than if you head it off with a proper application of fungicide.
• Growers should seek to optimize fungicide use in order to hold the line on costs.
ALAN ORTLOFF, from left, president of the Clint Williams Company, Madill, Okla.; Marshall Lamb, director of the USDA/ARS National Peanut Research Laboratory, Dawson, Ga.; and Lee Talbot, Brooks Peanut Company, Samson, Ala., were among those attending the annual meeting of the Mississippi Peanut Growers Association.
Fungicides are a key component in a successful peanut production program, says Alan Henn, Mississippi State University Extension professor of entomology and plant pathology, and growers should seek to optimize use of these materials in order to hold the line on costs.
“You need to make judicious applications of fungicides when they’re needed to prevent and control diseases,” he said at the annual meeting of the Mississippi Peanut Growers Association.
To do that, growers should:
• “Set really clear boundaries about what to expect and what expenses you might have.
• Do your best budgeting ahead of time.
• Make sure you carefully select fields to be planted to peanuts.
• “Remember, you want to follow a three-year rotation — and soybeans, also a legume crop, shouldn’t be used.”
• Know the disease history of your fields.
• Where possible, use the Peanut Rx program to select fields that may be suited to a reduced number of fungicide applications. “It’s a really helpful tool. If you have questions about how to use it, give me a call and I’ll be happy to help you.”
• “Work collaboratively with the person who scouts your fields to anticipate problems that may arise. “You need to be talking together all the time about the what, when, and how of your fungicide program.”
When and what to spray should be tailored to the individual situation, Henn says.
“Phoning your neighbor up the road or down the road from your farm isn’t the way to determine this, because most of the time what’s going on in one production area doesn’t necessarily relate to what’s going on in another.”
Fungicides work primarily as a preventive, he notes. “Once you have a disease, it’s a lot harder to manage than if you head it off with a proper application of fungicide.”
In areas that have been producing peanuts for a number of years, as in Georgia and Alabama, Henn says producers and researchers have developed a conventional spray schedule. “Basically, it’s 30 days after planting for your first application, then every 15 days until harvest — seven fungicide applications for the production cycle.
“Weather is the key to peanut diseases, and they are heavily modified by climatic conditions. They’re worse in hot, humid, moist weather than in dry conditions.”
The NOAA long-term prediction for 2013 is for above average temperatures in Mississippi during the growing season, and equal chances for above normal, below normal, or normal precipitation through July, Henn says. “Beyond July, NOAA is saying there are above normal chances for rains August through October, when we’re most likely to have tropical storms and wet systems coming off the Gulf. “
Early and late leaf spots, major problems in neighboring Alabama and in Georgia, have thus far not been a problem in Mississippi, he says. Rather, last year the state’s growers were mostly troubled by funky leaf spot and leaf scorch.
“Those infections, for the most part, come from over-wintering disease material and are in the field when peanuts come up the following year. Mississippi growers have been practicing really good rotations, which has helped to avoid a lot of leafs pot pressure and has saved a lot of money.”
Both early and late leaf spot were found in Mississippi in 2011 and 2012, Henn says, “but they were late in the season and just like Asian soybean rust, using the same ASR models, I’ve been able to link incidences to tropical storms moving up out of the Yucatan peninsula and over Texas, picking up disease spores from their peanut fields and raining them onto our fields
“About 20 days after a major rain event, you may see depressed, yellowing areas in fields due to leaf spots. Three days later, the spots will have spread more — these diseases are somewhat aggressive.”
A close examination, he says, shows the leaf spots to be “much darker than funky leaf spot, leaf scorch, and other leaf spots we’ve seen in Mississippi. If you have these rainstorm-related leaf spots, you’re going to need to be on a regular fungicide application schedule.