Breeder Suggests Better Resistance Over Fungicide

Corn fungicide craze helps most on susceptible hybrids.

Published on: Apr 24, 2007

There may be two kinds of farmers in Indiana right now- those who have already tried fungicides on corn, and those who haven’t but who will try it soon. It’s one of the hottest topics going heading into summer, partly because one of the big chemical producers, BASF, continues to push the concept.

Some farmers who tried it last year reported exciting results, even at $2.25 per bushel corn. It would be even bigger news at $3.50 per bushel corn. One large, well-seasoned north-central Indiana farmer saw such a response on a small field last year that he is preparing to treat nearly everything this year.

Yet other farmers report little or no yield advantage, and certainly no economic advantage, for applying a fungicide at tasseling on corn. Who’s right?

They both could be, says Dave Nanda, a 40-year plant breeder, president of Bird Hybrids LLC, Tiffin Ohio, and columnist and advisor for Indiana Prairie Farmer’s new section, Corn Illustrated, scheduled to be produced once per quarter.

If hybrids are susceptible to diseases, particularly gray leaf spot and/or northern corn leaf blight, then treatment with fungicides may pay off, Nanda says. Of course, disease pressure varies form year to year, largely varying upon weather conditions. So performance by a fungicide in terms of bushels per acre as an advantage, may vary as well.

Nanda predicts little if any benefit for fungicides on current hybrids with excellent disease resistance packages in place. There are several such products on the market, Nanda says. “My advice would be to work closely with your seedsman, pick hybrids that have excellent disease resistance, and not worry about applying fungicides,” he says.

Part of the problem with applying fungicides on corn, Nanda says, is a lack of information to base decisions upon. “There just hasn’t been much work done on it, and it’s fairly difficult to do,” says Greg Shaner, Purdue University plant pathologist.

Many issues need to be tested because many questions remain about this practice, Nanda asserts. For example, when should the product be applied? Is tasseling the best choice? Could more than one application be helpful in fields with relatively high disease pressure?

Shaner tells farmers several products are actually approved for application on commercial corn. However, the one you’ve likely heard most about is Headline, since BASF elected to push it for this purpose a year ago.

Other products now labeled, according to Shaner, include Quadris, Quilt and Stratego, plus these compounds outside the ‘strobin’ family: Tilt, Bumper and Propimax. There are also a variety of branded products featuring mancozeb fungicide.

“Farmers sometimes say it pays based upon their own strip trials, but they’re not giving us all the information we need to follow up and confirm it,” Shaner says. “They don’t record disease information for conditions that existed at the time of application and beyond.”

So visit with your seedsman and chemical supplier for deciding whether or not to apply a fungicide, and if you elect to do so, when and how to apply it, Nanda suggests.