What are effective organic methods to protect corn from pests?
Written by
Tina Carter
Reviewed by
Prof. Martin Thorne, Ph.D.Natural pest management preserves corn crops without ruffling an ecosystem. I've struggled with aphids in the field for many years until I switched to ladybugs. They wiped out 90 percent of the population in just 3 days. For a layered defense system, consider using a mix of physical barriers, natural sprays, and beneficial arthropods for the heavy lifting.
Soil Treatments
- Diatomaceous earth: Dust around stalks weekly to slice cutworm larvae
- Coffee grounds: Sprinkle to repel slugs and boost nitrogen
- Garlic spray: Blend 10 cloves/gallon to deter beetles
Biological Controls
- Ladybugs: Release 1,500/acre to eat aphids
- Trichogramma wasps: Parasitize corn borer eggs
- Nematodes: Water in Steinernema species for rootworm larvae
Neem oil interferes with the insects' hormonal systems while sparing bees. I mix 2 tbsp Cold cold-pressed neem into 1 gallon of water with a dash of Castile soap. Be sure to apply the mixture at dawn to avoid sunscald. Reapply after a heavy rain. This cut Japanese beetle damage by 75% last season!
Trap cropping attracts pests away from the corn. I grow 'Blue Hubbard' squash about 20 feet from my main crop. The vines are attractive to cucumber beetles, and they help to protect the corn. I check the traps each day and take any infested plants out of the field to break the breeding cycle.
Companion Plants
- Nasturtiums: Trap aphids away from corn
- Marigolds: Repel nematodes with root exudates
- Dill: Attract lacewings to eat earworm eggs
Cultural Practices
- Rotate crops annually to disrupt pest lifecycles
- Till soil in fall to expose overwintering larvae
- Remove crop debris to eliminate hiding spots
Handpicking pests is effective for small plots. To utilize this method, check the underside of leaves every morning when the pests tend to be sluggish. Drop hornworms in a bucket of soapy water. This saved 30% of my crop in 2023. Add sticky traps for winged pests like leafhoppers.
Read the full article: How to Grow Corn: 9 Essential Steps for Sweet Success
