GARDEN PESTS IN NEW ZEALAND 



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 larvae bore into the stem and destroy the pith, passing the 

 winter in the damaged canes. In the following spring the larva? 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 plcesiosema) . - Tomato 

 growers are frequently faced with the problem of the destruction of 

 tomato plants caused by the attacks of the larvae 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. 



The moth itself (Fig. 12c) is. a small one, measuring about a 

 quarter of an inch with the wings closed. In this position the insect 

 is wedge-shaped and conspicuous. Against the general greyish-brown 

 colour is a dark brownish area on each side. The eggs are laid on the 

 tomato leaves, in which the young caterpillars tunnel as they work 

 toward the leaf petioles, down which they burrow into the main stems. 

 In the damaged stems, pupation takes place. Under favourable condi- 

 tions, this insect may pass through at least three generations during 

 the season. 



Control depends upon sanitation and the use of arsenate of lead 

 sprays. All infested stems, together with plants after the crop has been 

 removed, should be burned; as the insect is known to attack potato 

 plants and tubers, cafe should be taken to destroy all potato tops after 

 harvesting. Frequent applications of arsenate of lead are essential to 

 protect the tomato plants, especially during the earlier part of the season. 



When on this subject, mention should be made of the potato-tuber 

 moth (Phthorimcea operculella) , which is somewhat similar to the 

 tomato-stem borer, both in appearance and habits. The larva of this 

 insect is best known from its habit of boring through potato-tubers; 

 these burrows become filled by a fungus after the larva? have vacated 

 them. The adult potato-tuber moth is a night-flyer, and lays its eggs 

 upon the leaves of the plants; the larva? burrow down the stems, and 

 may even reach the tuber below ground. When seed is not properly 

 buried, the moth will also lay its eggs in the "eyes," and so directly 

 infest the tuber; this danger applies also to potatoes in store or in bags. 



In the control of the potato-tuber moth, the following points should 

 be noted : Select only sound seed and cover well when planted. On 

 harvesting the crop, do not leave the bagged potatoes standing in the 

 field overnight, as they are exposed to infestation ; neither cover the open 

 bags with the potato-tops, as is commonly done, since this will attract 

 the moths. Destroy all tops immediately after harvesting. Dusting 

 potatoes in store with slaked lime will tend to act as a protection against 

 the moth. 



