No. 3/April 11, 1997
24(c) Label for Zinc Phosphide Pellets in No-Till or Reduced Tillage Corn
Recent approval of a 24(c) Special Local Needs label for 2% zinc phosphide pellets applied in furrow at planting time in no-till or reduced-tillage corn gives producers another option for rodent control. The label indicates a use rate of 4 to 6 pounds of the pelletized bait per acre for the control of small rodents like voles and field mice.
Zinc phosphide pellets may be most beneficial for corn that will be planted into fields with considerable residue, like CRP grass sod or green cover crops, that might harbor large densities of rodents. Recent field research with zinc phosphide applied at planting has characterized some advantages for its use, compared with other available options.
The application of zinc phosphide pellets in the furrow at planting
- controls the rodent population on site, thus preventing their movement into adjacent fields,
- allows maximum growth and benefit from cover crops before planting, without major concern for the existing rodent population,
- allows tenants to acquire and plant land without prior application of a rodent damage control technique,
- provides more consistent, economically effective control of rodent damage than most other available control options.
To apply the pellets properly in the furrow, a grower must modify the planter slightly. Two options for planter modification are (1) using a modified rotor (PPK kit) for applying the pellets through the planter insecticide boxes and (2) attaching a Gandy PDM applicator and hoses for application through the planter seed-drop tube. If properly adjusted, both applicators do an excellent job of placing the pellets in the furrow when the amount of residue is large.
Total costs for the modifications to corn planters can be as low as $12.50 per row if a grower already has insecticide boxes on the planter. The cost may be as high as $300 per row if the complete electric-driven Gandy applicators must be purchased.
For information about the availability of these application options and zinc phosphide pellets, call Haco, Inc., (800)435-9632. The 2% zinc phosphide pellet bait is a restricted-use pesticide.
Other potentially effective rodent damage control options are discussed in detail on pages 153 to 157 of the 1997 Illinois Agricultural Pest Management Handbook. Copies are available at your local University of Illinois Cooperative Extension Service office.
Ron Hines, Senior Research Specialist, Dixon Springs Ag Center, (618)695-2790