Many gardeners have a love-hate relationship with caterpillars. Caterpillars eventually grow into beautiful butterflies, but to make the transformation, they need to devour large amounts of plant material. Some caterpillars, such as cutworms, can strip a plant of its leaves in a single night. Pesticides will kill most caterpillars, but the chemicals also kill other beneficial insects, such as ladybugs, earthworms and predatory wasps. Additionally, leaves and stems absorb the chemicals in pesticides, so they are not suitable for plants you want to eat. You can get rid of caterpillars without chemicals by practicing organic pest control.
Handpick caterpillars from plants as you find them. You may need to patrol your garden at night to find slugs and some caterpillars. Relocate the caterpillars to a different area, or kill them by dropping them into a bucket of soapy water.
Spray the foliage of plants with neem oil. Neem oil controls caterpillars and other pests, including whiteflies, leaf miners and thrips. It may also kill beneficial insects such as bees and earthworms, however.
Dust plant foliage with Bacillus thuringiensis, or Bt, powder. Bt is a natural bacteria that kills caterpillars, but it does not harm most other beneficial insects.
Invite birds and predatory insects into your garden. Hang a bird feeder to attract birds to the area. Ducks and chickens also enjoy eating caterpillars. If your garden lacks predatory insects, such as praying mantises, you can usually purchase a box of them from a garden center.
Surround seedlings with a rigid collar, such as a toilet paper roll or plastic cup, to ward off cutworms.
Lay a sheet of cardboard or plywood on the ground near your plants. Check under the board every morning. Slugs like to hide under the board at night, making it easy to capture them.
Shield plants with sheets of porous polyester fabric. Row covers allow light to reach plants while keeping pests away.
Plant herbs and flowers around your garden to repel caterpillars. Many insects dislike the scent of lavender, mugwort, sage and peppermint.
Practice crop rotation to cut down on caterpillar infestation. For example, don't plant tomatoes in the same place two years in a row.
Things You Will Need
- Dish soap
- Neem oil
- Bacillus thuringiensis (Bt) powder
- Plastic cups or toilet paper rolls
- Cardboard or plywood
- Porous polyester sheets
- If you have the space, consider planting a butterfly garden. Fill the bed with plants caterpillars love to eat, such as dill, milkweed, willow and sunflowers. Add plants that butterflies enjoy, including red clover, verbena and lantana. The butterfly garden will keep caterpillars away from other desirable plants.
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