Caterpillars can devastate flowers, vegetable crops or shrubs within a few days, but many gardeners prefer not to spray their plants with toxic chemicals to protect them. The alternatives to using these types of pesticides to control caterpillars include manually removing the pests, using physical barriers, encouraging caterpillar predators and crop planning. However, you might also want to try certain home remedies and natural products that are effective and aren't harmful to humans.

How to Remove Caterpillars From Plants

If you can find and remove caterpillars and eggs from your plants, you can stay a step ahead of these pesky pests. Caterpillars are the larval stage of butterflies and moths. After mating, butterflies and moths lay eggs on their host plant, often on the underside of the leaves. If you check your plants daily, you can often spot a caterpillar infestation before it gets out of control. As soon as you see one caterpillar, check the plant for more and for tiny eggs, which may be laid singly or in clusters. Remove all the caterpillars you see, dropping them into a bucket of soapy water if you're too squeamish to squash them. Crush all the eggs or pick off the whole leaf and destroy it if the plant has plenty to spare. Repeat the process daily.

How to Protect Plants From Caterpillars

Insect barrier fabrics effectively protect plants from caterpillars. Although you might not want to cover up your prized shrubs, barrier fabrics can save many vegetable crops from caterpillar attack. To be effective, the barrier must be in place over the crop before the caterpillar eggs are laid on the plants, or you'll only be protecting the developing larvae from their natural predators. Push short bamboo poles into the ground around the vegetables and cover the tops with small plastic plant pots to prevent the fabric from snagging on the poles. Drape the fabric over the poles and hold it tight to the soil with bricks or heavy stones. This method isn't suitable for crops that require pollination, like tomatoes (Lycopersicon esculentum).

How to Attract Beneficial Insects and Animals

Although it's a slower process than spraying, encouraging a range of wildlife to visit your garden is a useful long-term strategy to reducing caterpillars and other pest infestations. Beneficial insects that prey on leaf-eating caterpillars include chalcid, brachonid and ichneumon wasps. Don't worry; these aren't the kinds of wasps that sting people. You can attract them to your garden by growing plants such as carrots (Daucus carota var. sativus) and parsley (Petroselinum crispum) and leaving them to flower. Attract caterpillar-eating birds, like chickadees, nuthatches, orioles and warblers, by installing a birdbath or fountain and leaving an area of your garden to grow a little wild, which provides cover and nesting sites.

Crop Planning to Discourage Caterpillars

A wide expanse of its favorite plant is like an all-you-can-eat buffet to a butterfly or moth looking for nourishment for its offspring. To discourage and confuse flying insects that target your vegetable crops, avoid growing plants in the same family together in the same place year after year. Alternate rows of vegetable types, grow in mixed blocks and rotate crops around your garden every season.

Chili Spray to Control Caterpillars

Home remedies can be effective caterpillar repellents. If your plants are infested, try this recipe:

Grind 3 1/2 ounces of dried chilies in a food processor.

Add the powder to 1/2 gallon boiling water.

Boil the mixture for 5 minutes. Add 1/2 gallon cold water and 2 or 3 drops of liquid soap. Allow the mixture to cool. Test the solution on a leaf and wait 24 hours. If the plant shows no reaction, spray the chili mixture on the caterpillars every evening.

Natural Pesticides