You planted some hybrids with excellent resistance to foliar diseases. Other hybrids that you planted were only rated as ″good. ″ Now you’re wondering when you should look for disease, and what you should do if you find it.
A panel of three Indiana Certified Crops Advisers put together advice on scouting for disease and making fungicide application decisions. Their comments are pointed at whether you should make applications during tasseling, not earlier in the season.
The team includes Jamie Bultemeier, agronomist with A& L Great Lake Labs, Fort Wayne; Gene Flaningam, independent crops consultant, Vincennes; and Bryan Overstreet, Purdue University Extension ag educator, Jasper County.
Here is a four-step process.
Step 1: Start scouting soon.
Start looking as early as V2 for anthracnose leaf spot, Overstreet says. Many of the other diseases may not show lesions until later in the season. However, Flaningam recommends scouting from emergence through tasseling. He recognizes that the most critical time is just prior to tasseling.
Step 2: Pin down your seedsman.
Get more specific about the probability of fungicide response for each hybrid, Flaningam recommends. He believes that most seedsmen can help you fine-tune expectations about how well hybrids will hold up if disease occurs.
Step 3: Scout for disease lesions.
Examine plants in several parts of the field throughout the season for signs of disease, Bultemeier says. Waiting until August is too late, he insists. Look for discoloration of leaves, and examine those areas with a magnifying glass. You may not see classic symptoms until after disease impact begins. Some diseases will show up as early as June in some years, he adds.
Step 4: Factor in economics.
“Economics and figuring the odds of getting a return on your inputs are very critical this year,” Flaningam says. That’s true for fungicides, but it’s also true for any other product you might apply for corn, he emphasizes.