Tiny Leaf Eating Caterpillars in the Garden

Types of Damage

• Foliage-eating caterpillars leave different signs on your plants. Some, such as tent caterpillars, spin large silken nests between branches of your favorite trees and ornamental plants where large congregations feed voraciously on the glossy green foliage. Leafrollers, as their name implies, roll the leaves of fruit trees into protected, silk-lined feeding and pupating stations. Leafminers leave intricate patterns on the surface of leaves. Still others feed on leaves one at a time, leaving notched edges or completely skeletonizing the leaves from the veins out. Leaf tiers weave small silken shelters among leaves and the terminals buds of their host plants. When their shelter is complete, several leaves will be tied into a semi-tight ball.

Physical Appearance

• Not all tiny caterpillars are the same color, which is helpful when you're trying to figure out which type of caterpillar is chewing on your veggies or landscape plants. Foliage-feeding caterpillars are often greenish, but may also be white, pink, beige or even patterned. Size is also an important factor in identifying the pest. Caterpillars typically range from 3/8 to 2 inches long, but some are a bit smaller and others are much larger. Take note of the color and size of your pest, as well as which plant it's feeding on. For example, upon seeing a mature diamondback moth caterpillar in your vegetable garden, you'll notice it's light green and approximately 1/3-inch-long. If you see fall webworms in early or mid-autumn, however, you'll notice a group of approximately 1-inch-long, tubercle-covered orange or black caterpillars.

Host Plant

• Many caterpillars are host-specific and the adult females will lay their eggs on or near the host plant. Cabbageworms, which reach up to 1 1/4 inch at full maturity, and cabbage loopers, which reach only around 1 1/2 inches, prefer to feed on cole crops. Checkerspot caterpillars, which grow to barely over 1 inch long, prefer to feed on the foliage of commonly planted garden wildflowers. When you see a caterpillar, take note not only of its appearance but what plant it's on or near for help identifying it.

Management

• In most cases, management isn't necessary because the caterpillars cause only aesthetic damage to the plant. If you notice that your plants are becoming nearly defoliated, have stunted growth or are producing no blooms or weak blooms or fruits, it may be time to step in. Remove heavily infested branches and dispose of them. Choose an insecticide labelled for the particular caterpillar. Take note that many insecticides will also kill beneficial arthropods and should be used only as a last resort. Many natural pesticides are commercially available to consumers.