CATERPILLARS

There are many different species of caterpillars so nearly everyone will encounter them at one time or another, usually in the garden, though some will invade greenhouses. They are the larvae of butterflies and moths such as cabbage moth, cabbage white butterfly or tomato moth.

Many caterpillars hatch in spring from overwintered eggs, others overwinter in a chrysalis or cocoon, emerge as a moth or butterfly in spring, mate, then lay eggs on the leaves or fruit of the host plant. The emerging caterpillars then feed on the leaves, they are voracious eaters and can be extremely destructive. Some species of caterpillars have been known to defoliate whole trees.

Caterpillars have chewing mouthparts with which to chomp through the foliage and some of the larger ones, for example, the tomato hookworm have actually been heard munching away. Early detection is essential as the irreversible damage that caterpillars cause often happens very rapidly.

Some caterpillars eat only one type of tree or plant while others eat a variety. One of the most common garden caterpillar is the cabbage looper and it enjoys the leaves of cabbage, lettuce, kale, parsley, potatoes, spinach, tomato, nasturtium and carnations to name a few.

Control

• Hand picking of caterpillars is very effective if the number of plants affected is small.
• Cover the plants with Garden Fabric to prevent eggs being laid in the first place.
• Scatter large pieces of egg shell to deter the cabbage white butterfly (it will mistake the shells for other butterflies and leave to look for an area less populated)
• After harvest bury the spent crops to destroy any cocoons before the adults emerge in spring.

Biological Control

• Caterpillars have a number of insect predators including lady bugs and lacewings, which eat the moth eggs, and wasps which will help to keep the caterpillar numbers down. Attract them with pollen and nectar plants, others which are useful are parsley, dill, fennel, alyssum and tansy.
• Encourage small insect eating birds to the garden by providing water and nesting places.

Chemical Control

Choose the least toxic spray to reduce the impact on the good bugs. Consider Ortho Max Bug-B-Gone which will not harm plants and is extremely safe.

Garlic spray is also useful as a repellant and to kill caterpillars.

Find out about other Garden Pests.