NEW ZEALAND 385 



ventralis are larval parasites. The two wasps, viz., Tiphia 

 popillivora and T. vernalis, are ectoparasites of the beetle larva? 

 (Clausen, King and Teranishi, 1927). Other species of parasites 

 have been introduced since that year, but the total area so far 

 colonised is too restricted to warrant any definite forecast being 

 made as to the final outcome of these biological measures. 



New Zealand. In so far as forest pests are concerned the 

 introduction into New Zealand of the Coccinellid Rhizobius 

 ventralis from Australia in 1900 for the purpose of controlling the 

 eucalyptus scale (Eriococcus coriaceus) has proved exceptionally 

 successful. The eucalyptus leaf weevil (Gonipterus scutellatus) is 

 now present in greatly reduced numbers in the North Island owing 

 to the activities of the Mymarid Anaphoidea nitens which was 

 introduced from Australia in 1927. The golden oak scale 

 (Asterolecanium variolosum) is stated to be under adequate control 

 in most localities owing to the introduction of Hahrolepis dalmanni 

 from the United States. The control of the " Chermes," Pineus 

 pini, was attempted in 1932, when the Agromyzid fly (Leucopis 

 sp.) was introduced from England, but so far no satisfactory 

 results have been obtained. The introduction of the large 

 Ichneumon Rhyssa persuasoria in 1928 for the purpose of 

 controlling the wood wasp {Sirex noctilio) has apparently resulted 

 in its becoming established, but the economic outcome of the 

 project cannot yet be forecasted. The Cynipid Ibalia, introduced 

 about the same time, proved a failure. 



As regards fruit pests, the reduction of the cottony-cushion 

 scale to the status of an occasional and minor pest of citrus, pear 

 and apple by the efficacy of the Coccinellid Vedalia cardinalis is 

 now well known. The control of the woolly aphis of apple by the 

 introduction of Aphelinus mall from the United States in 1921 is 

 an outstanding example of the biological method. The Aphelinus 

 is now successfully established throughout New Zealand and its 

 host has been reduced to the condition of a minor pest.^ 



1 The importance of Aphelinus mali as an agent in the control of the woolly 

 aphis of the apple has attracted almost world-wide attention {vide Howard, 

 1929). In several countries of South America it is now well established, and 

 exercising a high degree of control ; in Argentina the control is stated to have 

 exceeded all expectations. In Italy it has been introduced from Uruguay and 



R.A. ENTOMOLOGY. 13 



