GARDEN PESTS IX NEW ZEALAND 



abdomen seeming as one-; a second more waxy scale is now formed. 

 After a second moult, the adult appears, and resembles the second stage 

 larva in form ; the adult constructs a third scale, very much larger than 

 the earlier ones, to which it remains attached by its anterior end. 



Though many of the specialised coccids form elongate scales, as in 

 the case of the mussel-scale, numerous others construct circular scales, 

 as does the San Jose (Fig. 5) ; in the latter, the second and third scales 

 are constructed round the first, so that the first and second appear as 

 pimple-like structures in the centre, or slightly to one side of the com- 

 pleted covering. As with the olive scale, the covering of the specialised 

 forms serves as a receptacle for the eggs (Fig. 5). 



Some of the more important coccids occurring in ]STew Zealand will 

 now be discussed. 



CQTTOXY CUSHION S.CALE (Icerya pwrchasi). This insect (Fig. 

 6a) is a native of Australia, but has now become established in many 

 other countries, including New Zealand. For a time it was a serious 

 pest of citrus, until the introduction and establishment of its natural 

 enemy, the ladybird beetle (Novius cwrdinalis). 



The adult female is more or less oval, and covered with a yellowish 

 powder, partly concealing the reddish-brown ground colour and dark 

 spots along the sides of the body; the legs are black. A characteristic 

 feature is the white corrugated egg-sac attached to the end of the body 

 (Fig. 5). As the eggs are laid, this sac increases 'in size, until it may 

 measure fully 2-J times the length of the parent, which becomes tilted 

 up. The eggs are orange-yellow, and as many as 800 may be produced 

 by a single female. The eggs hatch in about a fortnight during summer, 

 and the period of development to the adult ranges from three to five 

 months. The larvae most frequently congregate along the mid-ribs of 

 leaves, and as development advances they usually migrate to the twigs 

 and branches. There are two generations each year. A considerable 

 variety of plants is attacked by this insect, chief among which are citrus, 

 acacia, gorse, wattle, and Douglas fir. 



Control is effected by the agency of the ladybird, but epidemics 

 sometimes occur with which the beetle cannot immediately cope; in such 

 a case fumigation in the glass-house, or spraying with red oil in the open, 

 should be resorted to. 



MEALY BUGS. Mealy bugs are characterised in the female by the 

 nature of the waxy protective secretion which forms a powdery meal- 

 like covering over the body, but is developed as a fringe of leg-like 

 processes at the side (Fig. 6b) ; these processes at the posterior end of 

 the insect may be prolonged as longer or shorter tail-like appendages in 

 some species, or they may be no longer than those fringing the body 

 margins in others. Immediately after each moult the larvae are devoid 

 of mealy covering and lateral processes, which are secreted anew each 

 time the cuticle is shed. In a mealy bug colony are numerous small, 

 narrow cocoons, in each of which a developing male 'insect lies. 



Most mealy bugs produce eggs, which are laid in a spacious, cottony 

 sac secreted at the posterior end of the female; the female insects, egg 

 sacs, and male cocoons together form characteristic woolly masses on 

 infested plants. 



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