WAS horrified to find my 10-year-old kowhai had been attacked by
voracious caterpillars. We live on a farm where there are no other
kowhai trees around and I have never had this happen before. They
did not like the shower of fly spray I gave them, but is there anything
I can do to prevent my poor tree being attacked again?
moth caterpillars regularly strip the foliage from both young and
mature kowhai. Damage happens most often from summer through to
autumn and in most cases the tree suffers very little permanent
damage. A healthy tree soon throws out a full set of new leaves,
so often there's little need to try to control them. Most times
you don't realise the caterpillars are there until the damage is
so bad it's too late to do anything about it.
If you do notice a few
caterpillars on the tree, you could spray with the low-toxicity
insecticide Success Naturalyte, which controls almost all types
of caterpillars. It can take several days for the caterpillars to
die following spraying with this product, so don't panic if nothing
happens right away.
A trick I learned recently
is that if the tree is small enough for you to give it a good shake,
a lot of the caterpillars will drop off on to a sheet laid on the
ground beneath and you can dispose of them.
Also worth remembering
is that quite a few parasitic wasps and other bugs feed on the kowhai
moth caterpillars, so if you can maintain a healthy insect population
in your area, the kowhai tree may be less likely to be badly affected.
Gardener, Issue 196, 2006, Page 39
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.