The last several years of wet and warm conditions in dairy regions across the country have brought up the important conversation of forage hygiene. If you ask University of Wisconsin-Madison Associate Professor and Field Crops Extension Pathologist Damon Smith, the “dirty forage” bull’s-eye is actually a triangle.

In order for many plant diseases to flourish, the three corners of the disease triangle have to be present. That is, a susceptible host, virulent pathogen, and favorable weather conditions.

“Those three things have to come together in order to have a disease concern,” Smith said at the recent Purina Leading Dairy Producers Conference. “The moving target, of course, has been the weather the last few years. Warm and excessively wet and humid conditions promote disease causing species.”

Action steps on corn
Specifically, when discussing ear rots in corn, Smith conveyed a handful of recommendations to help curtail its risk and impact. “Choosing hybrids is one of the biggest things you can do,” Smith said. “Choose something that has good ratings but also fits your climate.”

Here is the rest of his advice:

  • Plant early and allow normal heat unit accumulations
  • Irrigate if the plant is dry to reduce stress but irrigate deep and allow as much time as possible between irrigation events
  • Manage insects to minimize plant damage
  • Harvest at the optimum moisture to facilitate proper fermentation
  • Pack the bunker quickly and to adequate density
  • Consider fungicide use if necessary

To the final point of fungicide use, Smith said that fungicides should be considered for use on fields that have higher risk. Those risk factors include if the field has been infected before, if it receives irrigation, or if you have planted a less resistant hybrid. Typically, fungicides provide a quality improvement while seeing moderate to very low yield improvements.

Beyond the ear and leaf risk for corn crops, Smith concluded by warning of the likelihood of stalk infection in corn plants. “Where does vomitoxin accumulate in the plant? We’ve done some research that show these organisms can be stalk rotters, too. In 2019, there was a high stalk impact.”

Part of that he explained is tied to soil borne infection, but it’s something to be aware of in years where it’s excessively wet throughout the season.

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(c) Hoard's Dairyman Intel 2020
February 3, 2020
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