Reduce your anxieties about corn borer

Your seed is likely purchased, but all your hybrid selections may not be nailed down. How much should you worry about whether every hybrid has corn borer resistance? Put into dollars and cents, is it worth paying for if you have a choice?

The Indiana Certified Crop Advisers panel tackles this question.

Some seed companies basically throw in the corn borer resistance trait in Indiana, but my company doesn’t. It costs me about $10 per acre. Is it worth the investment on 1,000 acres of corn?

Betsy Bower, Ceres Solutions, Terre Haute: The first question to ask yourself is: “Have I been seeing yield loss from corn borers?” If not, you probably don’t need to invest in the trait. If you don’t know, then you may want to try some hybrids with the trait.

Purdue University did report higher numbers of corn borers in 2011, but the numbers were still low enough not to be a concern overall.

There is still no confirmed resistance of corn borers to the trait. If you don’t use the trait, then you should scout for first-generation corn borer and treat if necessary.

Ryan McAllister, Beck’s Hybrids, Parker City: I’ve heard a lot of noise that we’ve all but eliminated the corn borer. Maybe we hear it because there are so many corn borer-traited acres, and you simply don’t see visual signs.

If you would follow me to some of our non-GMO customers, you would appreciate the value of the trait. When corn borer reaches economic threshold levels, it’s been common to weigh a 6- to 10-bushel difference between a corn borer hybrid and its non-GMO genetic equivalent.

Are we seeing less corn borer? Yes. Is it worth the risk to me? No. Ten dollars per acre is about a bushel and a half. That’s cheap peace of mind.

Jeff Nagel, Ceres Solutions, Lafayette: Most likely it will pay, but seed decisions should be based on genetic yield potential first, and then yield protection traits. Sometimes the best genetics already contain the insect-protecting traits.

European corn borer numbers have decreased overall with wide adoption of traited hybrids. In northwest Indiana, we are more concerned with the potential impact of western bean cutworm. Ironically, western bean cutworm damage was lower this year, but we observed several fields where 30% to 50% of corn plants exhibited early European corn borer damage. This damage was on refuge acres or non-traited fields. The trait would have returned a profit in those fields. Usually, the trait that protects against corn borer also protects against some other insects. Odds are the $10 investment will provide an economic return.

When to scout for tough pests

Here’s when you will want to look for corn borer and some of the other worst insects on corn. Be especially alert with non-GMO corn.

European corn borer, first brood: June to mid-July, corn stage V6 (six leaf) to VT (tassel)

European corn borer, second brood: early July to early October, burrows in stalks

Western bean cutworm: early July into October

Armyworm: Early May into early July

Fall armyworm: Mid-July into October

Corn rootworm: Larvae, end of May through July; adults, July into early October

Source: Purdue University Corn & Soybean Field Guide


Jan Samanek, State Phytosanitary Administration,

This article published in the February, 2012 edition of INDIANA PRAIRIE FARMER.

All rights reserved. Copyright Farm Progress Cos. 2012.