Although they don't look menacing, caterpillars can be extremely destructive in gardens and flowering trees. Caterpillars eat their way through leafy plants, flowers and fruits and lay eggs that will hatch into more caterpillars to continue the destruction. If not controlled, caterpillars can decimate a garden and even kill the plants in them. By physically removing caterpillars from the garden and by destroying their eggs, you can control a caterpillar population. Other nontoxic methods can also be applied to repel caterpillars to keep your garden safe from these pests.
Remove any visible caterpillars or caterpillar eggs by hand and destroy them. Caterpillars and their eggs can be destroyed by drowning them in a solution of water and dish soap or by burning them in a metal container by igniting crumpled newspaper.
Create your own nontoxic insecticide spray to ward off and kill horned worm caterpillars by filling a spray bottle with water and dish soap. Lightly spray the plants affected by caterpillars with this mixture. The dish soap will kill the caterpillars but will not harm your plants.
Remove tent worm nests from trees by winding them around a stick or by cutting away the branches to which the nest is attached. Destroy the nests by dousing them in kerosene or lighter fluid and burning them.
Scatter crushed white egg shells on and around the plants most affected by caterpillars. Certain moths and butterflies, such as the cabbage white butterfly, that visit these plants to lay their eggs will mistake the egg shells for other moths and may move on to other, less-populated plants to lay their eggs.
Set up bird feeders and birdhouses in your yard or garden. Birds are natural predators of caterpillars and moths; if you can attract more birds to the area, you will have more predators to prey on the caterpillars.
Create an environment in your garden that is attractive to wasps that will naturally prey on caterpillars. Plants, such as fennel, dill and spearmint, are known to attract a type of parasitic wasp that lays its eggs on caterpillars. When the wasp eggs hatch, the larvae feed on the caterpillar and kill it.