Garden Pests in New Zealand: A Popular Manual for Practical Gardeners, Farmers and Schools
John Stuart Mill · en
Although in New Zealand there is usually only one generation produced
each year, three or even four develop in other countries. The winter
is passed by the larvæ in their cocoons, and pupation takes place just
prior to the period when the moths emerge in the spring. As the moths
continue to emerge and lay their eggs for a period extending from
November to February, it is essential that regular applications of
arsenate of lead be made during that time in order to protect the fruit
from the larvæ hatching from the eggs laid by the moths. In localities
where the spring larvæ enter the calyx of the fruit, it is essential to
apply the first spray just after the petals fall, so that the poison
may lodge in the calyx before it closes. The removal of rough bark from
the trunks of both apple and pear trees is a help in controlling the
insect. Another method sometimes used is to band the tree trunks with
strips of scrim; under these bands the larvæ collect, and the former
can be later removed and destroyed with their tenants.
CURRANT CLEAR-WING BORER(_Sesia tipuliformis_).--This destructive
moth has been carried to and established in New Zealand, as well as
many other parts of the world. In currant gardens its larvæ cause
the death of canes by eating out the pith. The moth (Fig. 12b) is a
very conspicuous and beautiful insect; the wings, which expand to
about three-quarters of an inch, are transparent and bordered with
golden-purple, a bar of the same colour crossing the surface of the
fore wings; the body (about half an inch long) is metallic-purple, the
thorax having a yellow stripe on each side, while the abdomen, barred
with golden bands, terminates in a fan-shaped tuft of purplish hairs.
The moths are active each year in the spring, when they lay their
brownish, globular eggs singly on the bark of the currant canes. The
resultant larvæ bore into the stem and destroy the pith, passing the
winter in the damaged canes. In the following spring the larvæ become
active once more and approach the surface, where pupation takes place
shortly before the moths emerge.
There is only one generation each year, and control lies in the removal
and burning of infested canes in late winter.
TOMATO STEM BORER(_Gnorimoschema plæsiosema_).--Tomato growers are
frequently faced with the problem of the destruction of tomato plants
caused by the attacks of the larvæ of the tomato stem borer moth. This
insect caused considerable damage for the first time in Auckland some
fourteen years ago, though it was known in other parts of the country
as well.