LITERATURE 419 



establishment in New Zealand is now becoming achieved. With 

 blackberry the preliminary testing of the stem-boring Buprestid 

 beetle (Coroebus rubi) from South Europe has given unfavourable 

 results, since both the larva and adult gave evidence of capability 

 for attacking economically useful plants. The outcome has been 

 the discarding of the project of biological control of blackberry, 

 since no other insect was deemed safe for the purpose. Ragwort 

 control is being attempted by the introduction of the Hypsid 

 moth, Tyria jacobece, from England, but the results obtained are 

 not very promising. This insect has become established in various 

 parts of New Zealand, but the activities of parasites of indigenous 

 insects and unknown influences are proving deleterious factors. 

 Owing to these difficulties, a second ragwort-feeding insect is being 

 studied with the object of being utilised in place of Tyria. The 

 insect in question, Pegohylemia jacobece, appears to be an effective 

 seed destroyer in its larval stage and is a member of the Dipterous 

 family Anthomyidse. No liberations appear to have yet been 

 made, and its possible success is still in the balance. In the case 

 of Accena, the burrs become entangled in the wool of the grazing 

 sheep and the market value of this product is estimated to suffer 

 an annual loss of £250,000. In this connection the introduction of 

 the saw-fly, Antholcus varinervis, from South Chile offers promise of 

 checking the plant in question, but no liberations have yet been 

 made. The flea-beetle, Haltica virescens, has also been tested out 

 as a potential beneficial insect, but it had to be abandoned owing 

 to the revelation of polyphagous propensities. 



The present situation, therefore, as regards weed control in 

 New Zealand is that, although the project has not fulfilled the 

 promise hoped for by Tillyard, who originated the scheme, in 

 another ten years' time a useful degree of control will possibly 

 have been achieved in certain cases (vide Miller, 1936). 



Literature 



Burgess and Crossman, 1929. Tech. Bull. 86, U.S. Dept. Agric. 



Chamberlin, 1926. Journ. Econ. Ent., XIX., 302. 



Clausen, 1936. Ann. Ent. Soc. Am., XXIX., 201. 



Clausen, King and Teranishi, 1927. Bull. 1429, U.S. Dept. Agric. 



Compere and Smith, 1932. Ililgardia, VI., 585. 



