Plant Doctor Archive

Astelias being eaten

LOTS of large holes have appeared in the leaves of our astelia. Can you tell me what the problem is?

LOOKING at your photo my first reaction was caterpillars. Have a good look, especially underneath the leaves for caterpillars or their droppings. If you find any, you could simply deal with them using digital control (squash them between your fingers) or drop them on to the ground and give them a taste of the sole of your boot.

However, it may be too late - the caterpillars may have eaten their fill, turned into moths or butterflies and flown away. If there are lots of small caterpillars (which I doubt ,given the large size of the holes) you could dust them with Derris Dust or spray with a pyrethrum-based insecticide.

On the other hand, weta can also cause this sort of damage without you even knowing they are around. In my experience, though, they tend to chew along the edge of a leaf and many of your holes are in the middle. Weta come out at night and munch away on quite a range of fleshy foliage plants and there's nothing you can really do about them.

Another possibility, but less likely given the look of the holes, is slugs and snails which should be easy to check out as they leave slime trails on the leaves.

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