How to Get Rid of Cutworms in a Vegetable Garden

You need to monitor your vegetable gardens for cutworms.

Cutworms are caterpillar larvae that can devastate a home vegetable garden. Appropriately named, cutworms completely cut through the stems of plants. They can do this either above the soil or just below it. Cutworms generally do their work at night, so you may not even know you have them until the next morning when you notice all of your plants on the ground. If this happens, you will need to get rid of the cutworms before they have time to multiply.

Things You'll Need

• Rototiller
• Diatomaceous earth
• Soup cans or pieces of cardboard
• Insecticide
• Sharp knife

Instructions

1. Make sure you definitely have cutworms before you begin a plan of attack. If you found your plants on the ground, begin digging up the soil within 1 square foot of the damaged plants. Cutworms can be between 1/2 inch and 1 inch in length, brown or gray in color and covered in tiny bristles. The cutworms will also curl up into a ball when you expose them.

2. Use a rototiller to till the ground just before you are ready to plant in the spring. This will expose, and even kill, any cutworms that may be living in the soil. It also helps eliminate plant residue that would encourage a cutworm to lay eggs.

3. Sprinkle diatomaceous earth around your vegetable garden. You won't need but a thin layer. The diatomaceous earth is safe to use around children and pets, but has tiny sharp bits that will cut the cutworms when they crawl over it. This will cause the cutworms to dehydrate and die.

4. Keep the cutworms from ever getting to the stems of your vegetables by cutting the top and bottom off of a soup can using a sharp knife and sliding it over the top of the plant, and then down the stem. It will act as a collar. The stem should be in the middle of the can without any of the sides of the can touching the stem. Make sure the can is at least 3 inches into the soil, and 3 inches above the soil. You can use a piece of cardboard to create a collar if you do not have a soup can.

5. Use an insecticide as a last resort. A permethrin-based insecticide will work to kill cutworms. You should make sure that you read and follow the product label to apply the insecticide correctly.

Tips & Warnings

• A layer of cornmeal can also be spread over the soil in your vegetable garden. The cutworms will eat it. When they do, it will kill them.

• The University of Minnesota recommends staying away from using green manure to fertilize your soil. It encourages the cutworms to lay their eggs.

References

• University of Minnesota: Cutworms in Home Gardens
• Golden Harvest Organics: Natural Insect Control: Cutworms