The Currant Fruit Fly. 241 



expensive on account of the kerosene and fuel consumed. Sub- 

 merging fruit in water for a period of two days will destroy all 

 of the larvae. When a sufficient amount of submerged fruit has 

 alccumulated, two days must elapse after the last addition of 

 infested fruit to the container has been made before burying or 

 plowing it in the soil. 



In view of the fact that the pest winters over in the pupa 

 stage in the ground below currant and gooseberry bushes, the 

 removal of the surface soil to a depth of three inches, dumping 

 and spreading it out on the road destroys the pupae. The soil 

 must be carefully removed below the network of rootlets. New 

 soil at some distance away from the bushes should replace that 

 removed. Few infested fruits were found in the currant patch 

 thus treated but it must be noted, however, that no data could 

 be obtained as to the infestation during previous years in this 

 garden. 



Sifting the puparia from the soil instead of removing and 

 replacing the ground under the bushes proved to be an unsatis- 

 factory method. The earth was first sifted through a one-quarter 

 inch mesh wire netting, so as to break up the lumps and to 

 remove the roots and grass, then as much of the soil as possible 

 was passed through a mosquito wire. It was found that the 

 smaller puparia passed through the meshes of the mosquito 

 wire. Sifting the soil through wire netting with meshes smaller 

 than screen wire would be an exceedingly laborious task. 



Stirring the soil with a rake several times a week during 

 the spring so as to expose the puparia to the natural enemies 

 and sunshine did not prevent the emergence of some of the flies. 



For several years each spring a farmer had placed coal and 

 wood ashes upon the surface of the soil below currant and goose- 

 berry bushes. Currant fruit flies issued in cages placed over 

 hoed ashes but none emerged from compact ashes. An exam- 

 ination of the crop showed the presence of maggoty fruit but 

 the infestation was not so severe as in currant and gooseberry 

 gardens situated at a distance of 315-565 feet. 



Various proportions of the following chemicals placed on 

 or in the ground to destroy the larvae, pupae or adults upon 

 emerging, did not give promising results as a method of control : 

 sulphate of iron; unslaked lime stirred in soil ; unslaked lime 

 on infested berries or on soil ; lime slaked on infested fruit or on 



