Nov., 1912.] ANNUAL REPORTS. 31 



trol was determined and this was at once made available for the fruit growers 

 of the State by the issuance of circular No. 14. 



The detailed report of the results of this investigation will be ready for 

 publication this winter, as a bulletin of this Station. The various projects 

 that have been carried through include: the extent of infestation by the apple 

 maggot in the State; the susceptibility of various varities of apples; the de- 

 terioration of infested fruit in storage as compared with uninfested fruits; the 

 accurate life history of the species; the habits of the species; the possible 

 means of control. 



It will be desirable to continue work on this insect in a minor way next 

 season, in order to verify certain facts and to clear up two or three points 

 that have been difficult or impossible to determine. These points do not 

 vitally effect the entire work but they should be completed. They include 

 further experiments to determine the average distance to which the adult 

 flies will travel, under natural conditions, the percentage of adults that emerge 

 the second season, instead of the first, following the pupal stage; further 

 tests with live stock, especially pigs and poultry. 



The above matters were under consideration this season, but were impos- 

 sible of definite conclusions, because of an unusual lack of abundance of the 

 pest. 



Control of Root Maggots. 



All of the work done so far under this project is preliminary in its nature 

 It is necessary, first, to overcome the technical and mechanical difficulties 

 in the way of favorable investigations, and these have not yet been satis- 

 factorily solved, although solution appears to be nearer. No results are yet- 

 ready for publication under this project. 



The fundamental aim of the project is to determine the basic rules for the 

 use of insecticides beneath the surface of the ground that will kill root maggots, 

 including such points as: the extent and rate of diffusion of poisonous gases; 

 the effective zone of poisonous liquids; the effects of various chemicals under 

 each of the above classes on animal life; the effects of the same on vegetable 

 life; and other similar questions. 



Work on this project will constitute the major part of the investigations 

 of the coming winter. 



INVESTIGATIONS UNDER HATCH FUNDS. 

 The Control of Black Flies. 



For two successive seasons extensive field experiments have been under 

 way at Dixville Notch, New Hampshire. In each of these two seasons an 

 entire section, including about eight square miles, has been treated for black 

 flies. 



Unexpected new facts were discovered in the life history of this pest, as 

 regards, at least, one of the species concerned. While these new facts do not 

 have a direct bearing on the manner of treatment of the pest, they immediately 

 concern the program or schedule of treatment. 



