Plant Doctor Archive

Caterpillars eating kowhai

OUR young kowhai tree, planted last spring, is covered in caterpillars and has lost almost all its leaves. Will it die?

KOWHAI trees are often attacked by caterpillars of the native kowhai moth, which also feed on non-native plants like broom, lupins and clover. The caterpillars can strip off every leaf then, when they run out of food, they either pupate (if mature enough), turn into moths and fly away, or die of starvation.

The good news is your tree will almost certainly survive and grow away again. You could spray the tree with Success Naturalyte or one of the many pyrethrum-based products, or dust it with Derris Dust to control the caterpillars. As your tree is still young, I'd recommend doing whatever you can to encourage fresh new growth - fertilise and water if necessary and mulch over the root system.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.