Hawk Moth Caterpillas
Hawk Moth caterpillars, which usually appear in February, are medium to large in size, with stout bodies and five pairs of legs. Usually the hawk moth caterpillars’ bodies lack any hairs, but most species have a ‘horn’ at the posterior end. Many are greens and browns, and have counter-shading patterns that help to conceal them.
The elephant caterpillar (hawkmoth Deilephilia elpenor) is the one mostly found in South Africa. It grows to up to 10cm in length and is a voracious feeder. It is readily recognised on plants, both by the droppings and the damage done to the leaves. They can denude a small plant overnight.
Female hawk moths lay translucent greenish, flattened, smooth eggs about the size of a tomato pip. These are usually laid singly on host plants and take between 3 to 21 days to develop. Most species are capable of producing several generations each year if weather conditions suitable.
As soon as you see a leaf with the characteristic half-moon piece eaten away, search under the surrounding leaves for the tiny, pale green newly-hatched caterpillars (right). For the first few days they lie along the midrib on the underside of the leaf – their ‘horn’ usually gives them away.
Another sign of the caterpillar’s presence is small black droppings that appear on the surface of leaves. You then need to get your eyes into ‘caterpillar mode’ and carefully search the underside of the leaves above this to find the culprit.
As the caterpillar matures, it spends the daylight hours on the centre branch near the base, in the soil, under the mulch or against the edge of the pot: they are experts at camouflaging themselves, taking on the colour of their surroundings.
The only effective remedy is early diagnosis so that you catch and dispose of them before too much damage done; pay your sharp-eyed grandchildren to do so!