University of Illinois

No. 2/April 3, 1998

Rodent Control in Corn

No-till corn growers who have suffered significant damage caused by rodents, particularly voles, have a new tool available for battling these critters. Within the past few months, Zinc Phosphide Pellets, manufactured by Haco, Inc., and marketed by Loveland Industries, Inc., wasfederally labeled for rodent control in no-till corn. The label indicates that one application of the pellets at 4 to 6 pounds per acre should be made at planting time. This product can be applied only with equipment specifically designed or modified to place the pellets in the seed furrow. Surface broadcast treatments are prohibited. Trials conducted by Ron Hines, senior research specialist at the Dixon Springs Ag Center, have revealed that zinc phosphide pellets applied in the appropriate manner provide good control of rodents in no-till corn.

Growers who will be planting corn into CRP acres (Conservation Reserve Program) this year may wish to assess the potential for rodent damage by "scouting" the field before planting. An "economic threshold" of five vole colonies present in a field 30 days before planting has been proposed. We have learned that the numbers of vole colonies in some CRP acres south of I-74 are considerably larger than 5 per acre. If the mild weather fostered better survival of rodents over the winter months, we should not be surprised to experience some problems with rodents in no-till corn this spring.
Kevin Steffey (, Extension Entomology, (217) 333-6652