It’s not unusual for growers to give up 15 or 20 bushels of yield per acre in corn refuge sites during years with moderate corn rootworm pressure. Under heavy insect pressure, yield losses can top 100 bushels per acre compared to fields planted with corn rootworm biotech traits. With the required 20 percent of growers’ biotech seed acreage devoted to refuge crops, industry experts say it’s vital to protect yield and maximize production in those areas.

“Some growers don’t give their refuge acres a fighting chance to produce maximum yields,” says Gary Nowaczyk, regional product manager for CROPLAN GENETICS® seed, a brand of Winfield Solutions, LLC. “With a bit of planning and the right production practices, refuge acres can contribute significantly to growers’ bottom-line profits.”

Bob Schoper, manager of Agronomy Services for Winfield Solutions, advises growers to follow management strategies that will gain the highest yields from refuge acres. “Insecticides are available in a number of different formulations that deliver good control,” Schoper explains. “While corn rootworm and corn borer traits have proven most effective in protecting against these pests, we still have other tools that will help foster good yield on acres planted with conventional seed.”

Six Steps for Maximum Refuge Production

To help growers capture maximum yields in refuge acres, Schoper and Nowaczyk recommend these management steps:

1. Select the right refuge hybrid. Nowaczyk steers growers toward conventional hybrids with large, fibrous root systems that can tolerate some root feeding by corn rootworms and will provide drought tolerance and root-lodging resistance. Other desirable hybrid characteristics include large, girthy ears; upright leaves; very strong rinds; and early flowering. For corn borer refuges, select hybrids from the Western genetic family, which have built-in corn borer tolerance and thick shanks for better ear retention.
2. Choose the right maturity. Consider harvest order when selecting hybrid maturity, Schoper advises. Without the corn borer or corn rootworm traits, hybrids will be more susceptible to root lodging or stalk breakage, so choose hybrids earlier in the harvest sequence.
3. Select the right site. Nowaczyk advises keeping the following issues in mind when selecting a refuge site:
4. • In continuous corn fields, choose a site where last season’s earliest hybrids were planted. This practice will help avoid corn rootworm pressure from extended diapause egg hatches in later-planted corn fields.
   • Avoid sites with grassy weed problems. Not only can corn rootworms feed on grasses, but the weeds will compete with corn plants for moisture and nutrients, adding further stress to root systems that may be under attack from corn rootworms. If weeds do become a problem, manage them with an appropriate herbicide.
   • Avoid sites with heavy clay soils, compaction issues or other factors that restrict root growth and can lead to root lodging.
5. Use a flexible configuration. While growers have several options for refuge placement, Schoper advises growers to choose a versatile planting strategy. Planting the refuge in a block configuration may provide more options for scouting, insecticide and herbicide treatments, and early harvesting, if necessary. Whichever configuration is selected, Schoper advises growers to closely follow refuge planting and placement regulations to help preserve the benefits of corn rootworm and corn borer seed traits.
6. Scout regularly. The only way to predict future rootworm levels is to scout for beetle activity. Schoper notes that scouting after corn plants silk will give growers the insect counts needed to make control decisions.
7. Apply insecticide. When a corn rootworm refuge site follows a continuous corn or corn/soybean rotation in an area where rootworm pressure is anticipated, apply an insecticide at planting for effective insect protection. Insecticide seed treatments also are an option, but Schoper warns their effectiveness may be diminished under heavy corn rootworm pressure. When monitoring shows corn borers at threshold levels, refuge sites may warrant in-season insecticide treatments.

By following these steps for refuge management, Nowaczyk and Schoper see a win-win situation for growers and the future of these valuable corn traits.

“Most growers who have seen the yield potential with corn rootworm and corn borer traits don’t relish a potential yield hit in refuge sites,” Schoper notes. “With the right production practices, acceptable refuge yields are possible. And you’ll be making sure the corn rootworm and corn borer traits will be a viable tool for years to come.”

For a more information about corn rootworm and corn borer traits, as well as refuge options, contact your local CROPLAN GENETICS® seed agronomist or visit www.croplangenetics.com.