182 Maine Agricultural Experiment Station. 1917. 



Native Host Plants. 



The native host plants of Epochra canadensis are probably 

 the wild currants and gooseberries. The currant fruit fly was 

 bred from the fruit of the wild gooseberry (Grossiilaria oxya- 

 canthoides (L.) Mill.) which were growing in a pasture about 

 a mile from Orono, Maine. On June 28, 1915, 39 per cent of the 

 gooseberries on these bushes contained egg chambers of appar- 

 ently this trypetid. The fruit of the wild red currant (Ribes 

 triste Pall.) was also found to be infested, but it should be noted, 

 however, that the bushes were growing on the banks of a stream 

 at a distance of about 35 feet from some cultivated currant and 

 gooseberry bushes with practically all of the berries wormy. 

 Our observation on the wild black currant (Ribes americanum 

 Mill.) was limited to one bush located about 10 miles from 

 Orono, but not a single berry was infested. 



The distribution of the wild currant and gooseberry which 

 were found to be infested by Epochra canadensis in Maine is 

 as follows : 



Ribes triste Pall. Newfoundland to Alaska, and south 

 to New Jersey, Michigan, South Dakota, and Oregon ; 

 also in northern Asia. Grossiilaria oxyacanthoides 

 (L.) Mill. Hudson Bay to Yukon, British Columbia, 

 Alberta, Montana, North Dakota and northern Michi- 

 gan. 



Coville and Britton (1908, pp. 193-225) record 43 species 

 of Ribes and 40 species of Grossiilaria growing, independent of 

 cultivation, in North America. Within the range of Epochra 

 canadensis as determined with cultivated fruits, are 15 species 

 of wild currants and 8 of gooseberries occurring both in Canada 

 and the United States; also 11 species of Ribes and 18 of Gross- 

 iilaria recorded only in the United States. 



Destructiveness to Cultivated Fruits. 



The currant fruit fly is so serious a pest in the state of 

 Maine, that frequently the crop of currants and gooseberries 

 is a total loss. In Orono, some people have dug up and burned 

 their currant and gooseberry bushes, because the fruit was infest- 

 ed with maggots so that it could not be used. One person set 



