Pests: find out more CATERPILLARS

Caterpillars

The Pest

Caterpillars are generally less of a problem when broad-spectrum pesticides are used. In crops where biological control is practised however, they commonly cause damage that necessitates treatment. Young caterpillars feed mainly on the underside of leaves but can move to flowers and fruit (e.g. tomato moth), and skeletonise leaves as they grow.

The moth species whose caterpillars cause most damage are:-

» Tomato moth (Lacanobia oleracea) damages tomato, peppers & chrysanths.
» Silver-y moth (Autographa gamma) damages lettuce, peppers & chrysanths.
» Angleshades moth (Phlogophora meticulosa) damages peppers & chrysanths.
» Cabbage moth (Mamestra brassicae) damages peppers & chrysanths.
» Gothic moth (Naenia typica) damages chrysanthemums.
» Carnation tortrix moth (Cacoecimorpha pronubana) damages carnations, roses & chrysanths.
 

Caterpillar damage on Tomatoes

Caterpillar damage on pepper leaf

The exact life cycle depends on the species.  The amount of time spent as a pupa in particular can vary; some species emerge as adults within a short time while others overwinter as pupae.

Moths usually lay eggs on the underside of leaves. They hatch in a few days and the young caterpillars feed on the bottom layers of cells of these leaves. After a few days they disperse over the plant. As they grow, caterpillars start to feed more voraciously and skeletonize leaves. In the case of the carnation tortrix moth, leaves are spun together and the caterpillar feeds safely within.  When the caterpillar is mature it pupates. This sometimes happens on the plant, but more usually pupae are found on the greenhouse structure, on or in the soil.

In greenhouses there are usually several generations a year but pupae produced in the autumn usually overwinter in the pupal state. When this happens hatching takes place in the spring.  Within a short time the moths fly to plants to lay eggs.

Moth eggs

Tomato looper caterpillar