December, '14] SWEZEY: SUGAR CANE WEEVIL PARASITE 455 



THE INTRODUCTION OF A TACHINID PARASITE OF 

 THE SUGAR CANE WEEVIL BORER IN HAWAII 



By Otto H. Swezey, Honolulu, Hawaii 



The sugar cane weevil borer, Rhabdocnemis (Sphenophorus) obscurus 

 (Boisd.), has long been a pest in Hawaiian cane fields. It probably 

 became introduced along with shipments of "seed cane" from Australia 

 early in the history of the sugar industry in Hawaii, and for several 

 decades past has been generally distributed throughout the Islands, 

 occurring in all of the plantations, and causing considerable loss of 

 cane in many of them, often resulting in the destruction of half of the 

 cane in fields especially favorably situated for them. 



Various methods have been employed to check the ravages of the 

 pest, with more or less beneficial results. After the remarkal^le suc- 

 cess attending the introduction of the egg-parasites of the sugar cane 

 leaf-hopper from Australia in 1904-05, it was decided to endeavor to 

 find and introduce parasites for the borer pest also. Accordingly Mr. 

 F. Muir was engaged by the Hawaiian Sugar Planters' Experiment 

 Station to make a search for natural enemies of this weevil. 



After considerable exploration of other sugar cane districts in search 

 of the probable original home of the weevil cane borer and any para- 

 sites that it might have there, finally, at Amboina, in the East Indies, 

 in 1908, Mr. IMuir discovered a Tachinid fly ^ parasitizing a weevil 

 infesting sago palms. The parasite was so effective that it was some- 

 times found to parasitize 90 per cent of the borers. As this borer was 

 similar to the one in sugar cane in Hawaii (in fact, is to be considered 

 only a local variation of the same species), it was thought that the in- 

 troduction of this Tachinid to Hawaii should be attempted. In the 

 summer of 1908, efforts were made to transport this Tachinid to 

 Hawaii, by means of a relay breeding station at Hong Kong; but all 

 attempts failed. The stages of the journey were too long for the trans- 

 mission of the parasites in the pupal stage, and they would not survive 

 cool storage. 



Abandoning the transportation problem for the time being, Muir 

 proceeded to British New Guinea for further investigations. Here 

 he soon found the same Tachinid parasitizing a borer in sugar cane, 

 which, on comparison, proved to be unmistakably identical with the 

 borer in sugar cane in Hawaii. The Tachinid was found destroying 

 a high percentage of the borers. Immediatelj- plans were made for 

 the transporation of the Tachinid to Hawaii. Mr. Muir found that he 

 could breed the Tachinid on borers in cane in cages. Accordingly he 



iCeromasia sphenophori Villeneuve, Wiener Entomologische Zeitung, XXX, p. 81, 

 1911. 



