GARDEN PESTS IN NEW ZEALAND 



CHAPTER VIII. 



Boring and Underground Insects. 



CODLIN MOTH (Cydia pomonellaj The codliii moth caterpillar 

 burrows in developing apples and pears, and such "wormy" fruit 

 Is known to everybody. 



The moth itself is seldom seen, since it lies concealed until after 

 nightfall, when it becomes active and lays its eggs. The insect (Fig. 

 12a) measures about three-quarters of an inch long, and is inconspicu- 

 ously, though beautifully, coloured; the fore wings, which cover the 

 "body when closed, are light grey, crossed by fine bands of a darker hue, 

 giving the appearance of watered-silk, while at the extremity of each 

 wing is a large bronze spot; the hind wings, seen only when expanded, 

 are of a light brown colour. The minute flat eggs are laid on the foliage 

 of leaves, on the fruit, or even on young bark; they appear at first as 

 glistening white specks, but, as development advances, a red ring 

 develops, and finally a black spot just prior to the caterpillars hatching. 



In some places the first larvae developing in the spring enter the 

 fruit by way of the calyx, but under New Zealand conditions it is more 

 usual for entry to be made by boring through the skin of the apple. 

 Having completed their development in the fruit, the caterpillars bore 

 their way out and spin their cocoons beneath the loose bark of the tree 

 trunks; in these cocoons pupation takes place, and from them the next 

 generation of moths develops. 



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 larvae 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 larvae hatching from the eggs laid by the moths. In localities 

 where the spring larvae 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 larvae collect, and the former can be 

 later removed and destroyed with their tenants. 



CURRANT CLEAR-WING BORER (Sesia tipuliformis). - - This de- 

 structive moth has been carried to and established in New Zealand, as 

 well as many other parts of the world. In currant gardens its larvae 

 cause the death of canes by eating out the pith. The moth (Fig. 12b) 

 is a very conspicuous and beautiful insect; the wings, w^hich expand 



61 



