Does Corn Disease Affect Silage?

REDFIELD, Iowa (DTN) -- The weather across much of the Midwest has led to concerns with late-season corn diseases, but when it comes to cutting silage, there is less concern.

"This is a perfect year for disease pressure in corn fields with the amount of moisture we have had followed by the heat," said Iowa State University Extension forage specialist Shelby Gruss. "We are likely to see some early dry down, so producers who are cutting silage need to get out in their fields and see what the corn looks like."

Southern rust seems to be very common in corn fields this year. Gruss said this disease by itself won't cause many problems for silage-making, but combining it with other diseases such as stalk rot or ear rot could cause some quality issues with the silage as well.

EAR ROT COULD LEAD TO MYCOTOXINS

The ear rots such as Gibberella, Fusarium, and Diplodia, which are common in wet conditions, can lead to concerns of producing mycotoxins that will affect cattle health. Mycotoxins can cause diseases of the liver, gastrointestinal tract, respiratory system, immune system, reproductive system or kidneys. Gruss suggested if a producer is concerned about mycotoxins to test the feed. This can be done through the Iowa State University Veterinary Diagnostic Lab.

"The early dry down could cause poor grain fill and decrease digestibility on the silage also," she added.

Mark Licht, Iowa State University Extension cropping systems specialist, said wrapped tassels have been reported across the region. The main concern with this is potential pollination problems. Poor pollination can lower starch levels in the grain, which is a key component of silage quality.

SURVEY FIELDS FOR PROBLEMS

Gruss said the most important thing is to look at the entire plant and walk out into the field to see what the plants look like within the field prior to cutting.

"If the silage is too dry when packing, an inoculum can be added to make it pack better," she said.

After the fermentation has started, she suggested checking the pH level of the silage to be sure it is 3.8 to 4.2 for proper storage. If the pH is higher than that, the corn silage becomes less stable and needs to be fed first.

For producers who graze cornstalk fields later in the fall after corn has been combined, she sees less risk from any of the diseases, but the stalks could have less digestibility, which isn't as much of a problem since stalks are mostly grazed for fiber.

Jennifer Carrico can be reached at jennifer.carrico@dtn.com

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