Caterpillars are larvae of butterflies and moths. They are voracious feeders with a huge appetite, damaging leaves and fruits and able to cause serious economic losses in many crops.
Caterpillars damage plants by chewing leaves and in some cases as far as to the leaf nerves. Young caterpillars only scrape the underside of the leave and keep the transparent upper epidermis intact. Larger caterpillars also damage flowers, fruits and young shoots. Some species bore into stems and fruits, making them difficult to detect and to reach. Besides of feeding damage, their discharge, also called frass, fouls the plants.
All moths and butterflies go through 4 stages: egg, larva, pupa and adult. Depending on the species, the shape of each stage varies as well as the life cycle which may take anywhere from one month to a year. The eggs are a very small, round, oval or cylindrical shaped and some may be ribbed. They are usually laid on the leaves in clusters of up to 100. When the eggs hatch, tiny caterpillars start immediately feeding and grow quickly to a 15-fold in length. Caterpillars molt several times while they grow. Caterpillars are green to brown colored. They have 3 pairs of true legs on the thorax and generally 4 pairs of false legs on the abdomen. As soon as a caterpillar is fully grown, it pupates. It undergoes a complete transformation, called metamorphosis, to emerge as a winged adult. The wings have clear markings which is useful in determining the species.
Some of the most important species are:
Autographa gamma (silver gamma moth), Cacoecimorpha pronubana (carnation leafroller), Chrysodeixis chalcites (tomato looper), Clepsis spectrana (cabbage leafroller), Duponchelia fovealis (European pepper moth), Helicoverpa armigera (tomato fruitmoth), Laconobia oleracea (tomato moth), Mamestra brassicae (cabbage moth), Spodoptera exigua (beet armyworm), Spodoptera littoralis (cotton leafworm)