257 



Granular baits could be used in conjunction with a tilling program 

 to reduce the numbers in existing fly populations and prevent an increase 

 in fly numbers due to migrating adults. Attractiveness of baits could 

 conceivably increase as manure is dried by tilling and becomes less 

 attractive to flies. 



Sugar baits are routinely used by poultrymen to kill adult house 

 flies. They are easy to use and results are visible in a short period 

 of time. 



Efficacy of Synthetic Pyrethroids as Contact Residuals 



Although the house fly LD 50 for permethrin (JFU 5819) is above the 

 acceptable level of 1 ppm, the slope of the dosage-mortality curve indi- 

 cates that resistance may be building within the population (Hoskins and 

 Gordon, 1956). Such resistance has already been reported in mosquitoes 

 (Priester and Georghiou, 1978). The regression equation presented in 

 the results section was used to arrive at a tentative LD 90 of k5 ppm. 

 This is below the concentration rates of 500 ppm and 50 ppm tested on 

 wood, tin, and cement block templates in the laboratory. 



Permethrin (JFU 5021A) decomposed in less than 2k and 72 hr on 

 cement and tin surfaces respectively, but persisted up to 23 months on 

 wood. This was much longer than could be expected for organophosphorous 

 compounds (Hansens and Bartley, 1953). 



The wooden rafters in poultry houses were logical field application 

 sites because they are favorite overnight resting places for house flies 

 (Anderson and Poorbaugh, 1964a). Since synthetic pyrethroids were not 

 labeled for use in or around poultry houses at the time of the experi- 

 ment, selected compounds were sprayed on plywood panels which were hung 

 in ooultry houses at the tilling site after the panels had dried. 



