There are a number of cabbage worms, cutworms and tomato hornworms that plague home gardens year-round. These pests aren’t really worms at all, but they are the caterpillars (or larvae) of various moths or butterflies. They will eat up and destroy your plants if you’re not watchful.
Cabbage worms include cabbage loopers, diamondback moths, and imported cabbage worms. They will eat up almost any cole crop or cruciferous vegetable, like broccoli, kale, cabbage, Brussels sprouts, mustard, or cauliflower. Cutworms feed on a large variety of vegetables, including asparagus, beans, crucifers, carrots, celery, corn, lettuce, peas, peppers, potatoes and tomatoes. Tomato hornworms are fond of tomatoes, of course, but also other members of the nightshade family including eggplant, peppers, and potatoes.
If your crops are struggling because you’ve got an infestation of cabbage worms or hornworms, we’ve got some options to help you regain control over your garden.
- Pick them off. Don’t be squeamish! This is the simplest way to remove these pests immediately. If you’ve only got a few plants, pick off any caterpillars or eggs you see. Eggs are easy to wipe away, but caterpillars will need to be removed. Squish them or drop them in soapy water to kill them. Check your plants at least once a week, and be sure to turn over the leaves and check in the veins and little hidey holes. Sometimes they will curl and drop to the base of the plant when you turn over a leaf, so check everywhere.
- Cover your plants. Insect netting with hoops can keep insects and birds from getting to your plants in the first place. There are high-rise hoops available for tomatoes or other tall crops. Cut the netting to size for each bed, and remove it as needed for care or harvesting.
- Clean up your garden. Keep any crop residue to a minimum and remove it from the plants so that cabbage worms won’t be able to survive the winter. Good weed control can also eliminate any other hosts that these pests can live on. Keeping a three or four foot buffer of dry soil around the edge of the garden can also discourage these pests.
- Companion planting. Planting herbs and flowers strategically can help deter worm infestations by attracting beneficial insects. Try planting thyme, marigold, and nasturtium near your cole crops to keep cabbage worms at bay. Basil, oregano, and thyme are good companions for tomato plants.
- Leave natural enemies alone. Lady beetles, soldier bugs, wasps, and pirate bugs can help you protect your plants by feeding on these worms. If you do see a hornworm that has a white cocoon on its body, it has been attacked by a parasitic wasp. These wasps help keep the hornworm population under control. This is the one case where you’ll want to leave the worm alive. A parasitized hornworm eats only a fraction of the plant that a healthy worm does, so it’s up to you whether you want to remove it completely from the plant or relocate it nearby.
- Pesticides. It’s generally not necessary to use a pesticide, but there are a few options that are fairly safe if you feel like you need a little extra help. Neem oil is one popular option for keeping tomato hornworms at bay, and a mix of baking soda and cabbage is another homemade pesticide for killing cabbage worms and cutworms. Always follow instructions on the label and make sure any pesticide you choose is appropriate for the pests you’re trying to control and also for the plants you’re applying it to.
After your growing season is over, remember that proper rotation of crops is crucial to keeping pest and disease populations down. Cultivate the soil after pulling up your plants in the fall to expose the pupae underground. Chickens will gladly help you clean the area out, too. In the spring, plant something completely different in the area and start all over again.
With a little work, you’ll have these pests under control in no time and people will be asking you how you did it. Good luck, and happy gardening!
Cabbage, broccoli & other cole crop insect pests
Tomato hornworms in home gardens
Cutworms in home gardens
The tomato hornworm and the tobacco hornworm
Companion Planting: A Method for Sustainable Pest Control