GARDEN PESTS IN NEW ZEALAND 



CHAPTER IX. 



Miscellaneous Pests. 



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N" this chapter will be grouped for convenience mites, woodlice, 

 millepedes, slugs, snails, and eelworms. 



Mites. 



Mites, together with spiders and ticks, belong to a group of animals 

 distinct from the insects, from which, they differ in many respects; for 

 example, they possess four, and not three, pairs of legs in the adult state, 

 no head separated from the body as a movable, distinct region, while in 

 many cases, especially in mites and ticks, the abdomen and thorax are 

 continuous; in no case are wings developed. 



Mites are of small size, some being microscopic, while others are 

 just discernable by the unaided eye. All species have the mouth-parts 

 developed for the purpose of feeding upon liquid food e.g., blood (in 

 the case of those species that attack animals), decaying vegetable matter, 

 or the saps of plants. It is the last. that is, those parasitic upon 

 plants with which we are here concerned. 



The life-history of mites presents some variability, and, though 

 there are fundamentally four stages of development, additional stages 

 have been developed by some species which tend to complicate the cycle. 

 The principal stages in development are as follows (Fig. 13, 1 5) : 

 In practically all cases eggs are deposited, but few species being vivi- 

 parous. The larva, on hatching, possesses but six legs, and resembles 

 an insect in this respect; the larva then becomes quiescent, and after 

 moulting the eight-legged nymph appears. While in the nymphal state 

 the mite may undergo one or more moults, giving rise to additional 

 nymphal forms, that may complicate the life-history. From the final 

 moult of the nymph the adult mite emerges. 



Perhaps the best-known mite in New Zealand is the European red 

 mite of apple trees (Paratetranychus pilosus), though it attacks a wide 

 range of plants apart from deciduous fruit trees, which it favours ; it 

 has been found on grape vine, raspberry, rose, hawthorn, citrus, etc. 

 This mite (Fig. 13, 6) occurs in Europe, Russia, British Isles, North 

 America, Australia, and New Zealand, and it causes considerable injury 

 to foliage, which assumes a brown appearance, owing to the tissues 

 drying up where they have been punctured by the mouth-parts of the 

 mite. 



In the case of heavily-infested trees, the red eggs of this mite form 

 conspicuous patches on the bark during winter; these winter eggs are 

 laid from January onward till leaf-fall, and from them the young mites 



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