AgCenter scientist looks at management of corn diseases

Johnny Morgan, Gould, Frances I., Blanchard, Tobie M.  |  11/9/2017 8:50:59 PM

Corn producers know well that there are many diseases that can reduce yields in their crop throughout the growing season.

With this in mind, LSU AgCenter field crops plant pathologist Trey Price is conducting trials that evaluate seed in-furrow treatments and foliar sprays on corn.

“The biggest concern we tend to have in Louisiana is foliar disease management of corn,” Price said. “There are a number of foliar problems that are annual occurrences.”

Price’s corn disease management work is conducted at the AgCenter Northeast Research Station in St. Joseph, the Macon Ridge Research Station in Winnsboro and at the Dean Lee Research Station in Alexandria.

“The primary problem in corn fields when it comes to disease is northern corn leaf blight,” he said. “We see this every year, especially where growers have corn exclusively in minimum or reduced tillage systems.”

The main goal of Price’s research is to look at application timing on fungicide efficacy, he said.

“What we try to do is determine the most effective products and the appropriate timings to use them,” he said. “We also continue to look at the effect of fungicides in the absence of disease, since a lot of growers are under the impression that fungicides may increase yields or stalk strength. Many years of research on many hybrids at multiple locations has determined that these effects simply do not exist. Nevertheless, growers continue to apply fungicides in the absence of disease, so we must continue to mimic their practices in case something changes.”

Some corn was planted as early as mid-February this year, and growers began harvesting a week or two earlier than last year’s harvest, Price said.

“The reason we’re having northern leaf blight problems this year can be attributed to the weather,” Price said. “The pathogen prefers warm, rainy weather.”

Southern rust is another corn disease that has been monitored by Price’s research project. There has been light disease pressure at St. Joseph, light-to-moderate at Winnsboro, and moderate at Dean Lee, he said.

“We have trials for Southern rust and we have fungicides that are very effective,” Price said. “But in Louisiana in most years, we tend to outrun the disease. In other words, the crop matures before the disease can cause yield losses. Many producers believe that a Southern rust infection during late growth stages will result in lodging. This is simply not the case. We are working to document severe Southern rust outbreaks, monitor for lodging and collect data that will help our producers make prudent management decisions.”

Other evaluations in the study include rating hybrid trials, which can help producers decide which hybrid to plant. This may be particularly important in the case of northern corn leaf blight as tolerant hybrids may be available.

“However, we still work hard to provide valuable information for our growers as we can,” Price said.

The findings will be released the week before Thanksgiving 2017 at the latest, he said. “We try to get the findings out as soon as we can to help growers make decisions on buying their seed,” Price said.

Johnny Morgan

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