PUKATEA PROBLEM

Question We have several pukatea in our garden and some have lots of holes in the leaves. I managed to photograph some tiny caterpillars on them. Can you tell what they are?

J Robertson, Coromandel

Answer These are looper caterpillars, so called because they have three pairs of legs on the thorax and two pairs at the rear end; the back legs walk forward, creating the body ‘loop’, the front legs then walk forwards, straightening the body out, and so it goes on. The ones in your photo look to me like larvae of the kawakawa moth, which is most often found making holes in the young leaves of its preferred host, Piper excelsum (kawakawa).

The moths lay eggs almost any time of year so you can find caterpillar damage year-round. They feed on tender new leaves, making smallish holes like in your photo. As the leaf grows, the holes become more obvious, though often by the time you see the damage the caterpillar is no longer around – it’s pupated and turned into a moth. The caterpillars can reach 30–40mm long before pupating.

The adult moth is around 10–15mm long with a wingspan of 30–55mm and is very variable in colouration and mottling – yellow-brown, brown, blackish – with irregular lines.

Although kawakawa seems to be the favoured host plant, these moths have been found to lay eggs on quite a wide range of native plants and even the odd introduced species, such as tree lupin and eucalyptus.

I wouldn’t worry about them; they seldom do enough damage to warrant interference. Enjoy the presence of this native insect along with the plants.