University of Illinois

No. 3/April 10, 1998

Calibration of Planters for the Delivery of Soil Insecticides

Producers who will be applying a soil insecticide at planting should begin to make sure that their planters are properly calibrated. Insecticide planter boxes should be cleaned, and any worn or broken parts replaced. Remember, the suggested settings for hopper boxes should be relied upon only as a starting point in the overall calibration process. It has been shown many times that the amount of insecticide delivered by different planter boxes can varysignificantly, even though the same setting is used on each unit. The proper attention devoted to calibration can lead to the delivery of an optimal rate of the chosen product. The optimal rate should provide adequate root protection while minimizing undesirable environmental effects. The philosophy that "if a little does some good, then a lot will really increase rootprotection" couldn't be further from the truth.

The following procedures are outlined to aid producers during the calibration process.

  1. Note the manufacturer's recommendation for a proper applicator setting on insecticide boxes.

  2. Measure off 1,000 feet in a field for a trial run. Speed and traction conditions should approximate planting-time conditions.

  3. Attach an insecticide collection container (available from local dealers) to delivery tubes from each insecticide box. Then fill the hoppers with the insecticide.

  4. Conduct your trial at planting speed.

  5. Weigh the insecticide in each collection container. The following amounts of insecticide should be delivered per 1,000 feet according to the formulation percentage of a product: 15G--8 ounces and 20G--6 ounces. Aztec is a 2.1G formulation; 6.7 ounces of product per 1,000 feet should be collected. Force may be used as a 1.5G or 3G formulation; 8 to 10 ounces or 4 to 5 ounces, respectively, of product per 1,000 feet should be collected. Fortress may be applied as a 2.5G or 5G formulation; 6 ounces or 3 ounces, respectively, of product per 1,000 feet should be collected.

  6. The calibration procedure should be continued if the insecticide collected is 10 percent above or below the labeled levels. This is true for each insecticide box.

  7. If you have used blank granules (no insecticide loaded onto granules) during the calibration process, try the actual product before the planting process. The planter-box settings should deliver the same amount of material regardless of whether blank granules or the product has been used; however, make sure you verify this before you go to the field.Mike Gray (, Extension Entomology, (217)333-6652