How to Kill Weevils on Growing Corn

Identify the weevil. There are many different kinds of weevils including rice, boll and granary weevils. Before treating an entire field of corn, it is important to make sure that it is corn weevils attacking the crop and that the problem is widespread. Corn weevils are 1/8 to 3/16 of an inch in length. They are reddish-brown to black in color, and have four red spots on their backs.

Purchase a pyrethrin-based insecticide. This particular insecticide has been shown to successfully treat weevil infestations and will not harm the corn. Using insecticide should be done well before harvest to avoid any potential contamination.

Spray the crops with the insecticide. Commercial sprayers can be rented from local implement stores at a daily rate. For large applications, this will be necessary. A small field typically can be treated with an ATV and a small sprayer. Make sure all areas of the corn are treated.

Spray again after 14 days. To catch each ensuing generation, it will be necessary to spray as larvae hatch. Monitor the field and spray again if necessary after this point.

Heat the grain after harvesting. Heating corn to a temperature over 60 degrees Celsius will effectively kill any remaining weevils and their larvae. The downside to this treatment is that it may affect the quality of the corn and corn meal. For livestock feed, however, this method typically works well.