GARDEN PESTS IN NEW ZEALAND 



Another saw-fly closely related to the foregoing species is the willow 

 saw-fly (Pontania proxima). This species has only recently appeared 

 in Xew Zealand, and its larvae live in galls, or swellings, on the foliage 

 of willows. 



PEAR MIDGE (Perrisia pyri). A serious pest of pear trees, which 

 for some years retarded the culture of pears, especially in the Auckland 

 district, is the pear midge. This is a minute, delicate, two-winged fly 

 (Fig. 11, 6), measuring about one-twenty-fifth of an inch long; it has 

 a blackish head and thorax, and an orange-red to brownish abdomen. 

 The female alights upon young leaves just burst from the bud; and, 

 while they are yet curled, lays her eggs between the folds. The larvae, 

 on hatching, live protected in the curled leaves, which they attack, and 

 which never unfold. The result is that the infested leaves eventually 

 turn black and brittle, and cease to function. The fully-developed 

 larvae drop to the ground, which they enter, and there pupate. The 

 midges become abundant in early spring, when the first young pear 

 foliage develops* and they keep on producing generation after genera- 

 tion until the autumn. The Avinter is passed in the larval stage under- 

 ground beneath the trees. 



A parasite has been established against the pest, and is doing good 

 work. The insect can be reduced to a large extent by thorough winter 

 cultivation, especially beneath the trees. The insect's larvae, being pro- 

 tected within the curled-up leaves, are not reached by ordinary sprays, 

 but Dr. K. H. Makgill, of Henderson, secured some excellent results 

 on young trees by the use of nicotine. 



OLEARIA GALL MIDGE (Cecidomyia olecvrice). --In many parts of 

 New Zealand where Olearia forsteri is grown as a hedge, it is very often 

 disfigured by the formation of malformations, or galls. These are caused 

 by a native midge known as the olearia gall midge. The midge itself 

 resembles the pear midge in structure, but is larger, measuring from 

 one-tenth to one-eighth of an inch long; it is conspicuous on account 

 of. its black thorax and blood-red abdomen. In early spring the midges 

 appear and lay their conspicuous masses of bright red eggs upon the 

 buds of the developing shoots. The larvae, on hatching, set up an irrita- 

 tion in the rapidly-developing tissues, causing the latter to swell and 

 become malformed into bunches of rosette-like galls. If the latter are 

 cut open, a number of the yellowish larvae trill be found, each in its 

 own compartment within the fleshy gall. There is only one brood of 

 adults each year. Control can be effected to a great extent by cutting 

 back and burning the badly-infested parts during winter, and by pruning 

 the young growth carrying the eggs in the spring. Spraying with 

 nicotine when the midges are active should also help to protect the 

 plants. 



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