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l-ield studies were continued during the surr.mer of 1970 

 on the biology and control of the Greenhead Fly. r^xtensive 

 field trials v;ere conducted on the Essex County and Cape Cod 

 salt marshes v\T.th the use of various modifications of adult 

 Greenhead fly traps to attempt a protection to limited local 

 situations without the use of any pesticide. The majority of 

 traps were located in close proximity to recreational areas. 

 A total of 419 traps were installed in the North Shore Greenhead 

 Fly Project area and a total of 30'^ traps were installed in the 

 Cape Cod Greenhead Fly Project area. 



The reports from, both of ttie Greenhead Fly Projects have 

 net as yet been received but from preliminary reports the flies 

 that were caught in the traps were 90-3 female. The reports of 

 the ei'l'ectiveness of the traps have been somewhat conflicting. 

 Evaluation of the effectiveness of the traps has not as yet been 

 ccmpletod for this year. It '/viil probabl}'' take at least 3-5 

 years to obtain sufficient data as to their effectiveness. 



At present there appears to be little hope of finding 

 a chemical that will be both effective as a larvicide and 

 noniiazardcus to ncn-target organisms of the ecosystem of the 

 marshes . 



The Reclamation Board delegates to the appropriate mos- 

 quito control projects the responsibility for supervision of 

 the maintenance of the salt marsh ditching network, originally 

 constructed by hand labor in 1930 and 1931 • This maintenance 

 work is essential if the ditches are to function efficiently 



