Things You'll Need
Corn oil or mineral oil
Once insects are allowed to invade your ears of corn, they can destroy the crop that you have worked all spring and summer to grow. Insects that attack corn include corn earworm, corn borer, corn sap beetle, cinch bugs worms, and moths. Prevent these insects from damaging your crop by keeping them from reaching the sweet kernels developing inside each ear. With the proper steps and products, the ears of corn will be protected and develop into a healthy and delicious crop.
Apply five drops of corn oil or mineral oil to the silks on each ear of corn. Apply the oil to the silks only after they begin to turn brown. The browning of the silks indicates that pollination has occurred. The oil will create a barrier that will deter insects from laying eggs in the ear of corn.
Wrap the top of each ear of corn with a rubber band after the oil application. Make sure the rubber band is wrapped around all tips of the corn husks to ensure the ear is properly sealed. The rubber band will keep the tip of the corn ear closed, further denying access to insects.
Spray Bacillus thuringiensis (Bt) onto the corn leaves and over the silk on each corn ear. Bt can be purchased at a local nursery or garden center and is a bacterial insecticide that kills larvae of the corn borer. Read all package labels, instructions and warnings before applying Bt. Follow the package directions and rate of application when spraying onto plants.
Spread diatomaceous earth on the ground around the stalks of corn. Diatomaceous earth is a natural insecticide that comes in a powder form. The particles are sharp and will slice through the hard outer coverings of insects causing them to dry out and die. Read all package labels, instructions and warnings before using diatomaceaous earth. Wear a dust mask and goggles to avoid breathing in the dust and to protect your eyes from exposure.
Till in corn stalks or remove them from your garden after harvest. Do not allow cornstalks to overwinter on top of the soil as this will attract insects that will take up residence in the stalks.