Another Aussie Invader
Recent reports of damage to coastal banksia trees have been received from throughout the North Island. The trees appear to be badly sunburnt, with the young leaves and tips of older leaves turned crinkled and brown. In fact, the tiny green larva of a small, white Australian moth called Stegommata sulfuratella causes this damage. In Australia, it is found in New South Wales and Queensland.
Scientists first recorded the insect’s arrival in Auckland in 1999. Since then it has flown, or been carried in plants being moved to Northland, the Coromandel, Bay of Plenty, Taranaki, Wanganui and recently, Wellington. The moth could have been blown to New Zealand on a passing storm front, or may have accidentally been carried here in trans-Tasman cargo or passenger belongings.
The worst effect of the larva is when it chews out the insides of the young banksia leaves. This causes the leaves to fall off. Many people notice the scraggly appearance of the bare twigs or the hundreds of shed leaves littering their lawns in late summer. This little insect is in New Zealand to stay, and there is no effective means of control. So lovers of the coastal banksia (including the birds which feed on its flowers in winter) will have to get used to the way the insect now damages this plant.