Review how to stop rootworms

How do you control rootworms on refuge acres in Bt rootworm corn fields? Or how do you stop the pests if you’re growing non-GMO corn for specialty markets?

Even if you’re growing new SmartStax hybrids, controlling rootworm larvae on refuge acres is still an issue. Provisions granted by the Environmental Protection Agency drop the refuge requirement for SmartStax hybrids from 20% to 5% in the Midwest. You’ll still need to control rootworm larvae on that 5% of acreage. Other companies have applied for waivers to reduce refuge requirements for their products. But heading into 2010, the refuge requirement remains at 20% for all hybrids except SmartStax.

The Indiana Certified Crop Adviser’s panel looks at ways to still get the job done. Panelists include Greg Kneubuhler, G & K Concepts, Harlan; Jeff Nagel, Ceres Solutions, Lafayette; and Darrell Shemwell, Posey County Co-op, Poseyville.

Key Points

• Soil-applied insecticides are still a good choice for rootworm control.

• Seed-treatment insecticides have a niche, but not in high-rootworm-pressure fields.

• New delivery systems for granular insecticides make application safer.


What are my options today for rootworm control in fields where I’m either raising non-GMO corn, or planting refuge acres to complement Bt rootworm hybrids?

Kneubuhler: We’ve been proponents of soil-applied insecticides for years, even before universities recommended them. We’ve seen enough plots where soil-applied insecticides have paid that we’ve recommended them for years.

There are also seed-applied products available today, even for non-GMO corn, and they’re quality products. Those, coupled with a soil insecticide, have proven most beneficial. You have too much invested today in your corn crop not to protect it with a low-cost insecticide.

Nagel: The options are similar to years past. For soil-applied granular products, choose from Aztec, Force, Counter, Lorsban and Fortress. For soil-applied liquid insecticides, you’ve got Capture and Request. You’ve also got these seed-applied insecticides: Poncho 1250 and Cruiser at the high rate.

There are some new delivery systems, too, such as Force CS. It’s an option on some John Deere planters. Several products can be purchased for use through Amvac’s Smartbox system.

In areas of moderate to high rootworm pressure, such as west-central and northwest Indiana, we tend to see the top tier of granular insecticides provide the most consistent rootworm control. Growers like the convenience of seed treatments for refuge acres, but seed treatments are best utilized in areas where historical rootworm pressure is low to moderate.

Shemwell: The first option is to plant corn after soybeans. If you’re in an area where this is not an option because of the western corn rootworm beetle variant that lays eggs in soybeans, presenting you with the possibility of rootworm larvae available to eat first-year corn roots the following season, you will need a Plan B.

This plan may be to purchase your seed corn with Poncho 1250 applied to it. Another option would be to use a granular insecticide such as Force 3G, Lorsban 15G and so forth. That assumes your planter is equipped with insecticide boxes.

Still another option would be to add a liquid insecticide to your starter fertilizer. Apply it in furrow. Capture LFR would be a good choice in this situation.

This article published in the February, 2010 edition of INDIANA PRAIRIE FARMER.

All rights reserved. Copyright Farm Progress Cos. 2010.