56 CIRCULAR 9 7 7, U. S. DEPARTMENT OF AGRICULTURE 



For large, open rooms or buildings a power sprayer equipped with a 

 suitable nozzle and operating at low pressure may be desirable. 



In the field, latrines frequently become heavily infested with various 

 kinds of flies. In addition to larvicidal measures (see pp. 58-59), residual 

 sprays should be applied liberally to the inside and outside walls of 

 the structures and the inside walls of the vaults. 



Methoxychlor, a compound closely related to DDT, is also useful 

 against nonresistant house flies. Although less effective than DDT, 

 it is less toxic to mammals. Methoxychlor and lindane are the only 

 chlorinated hydrocarbon insecticides now recommended for use in 

 dairy barns or milk rooms. For fly control methoxychlor may be 

 applied essentially as recommended for DDT. 



Chlordane, BHC, and dieldrin are all more toxic than DDT or 

 methoxychlor to house flies, but since they are more volatile their 

 residual effect is of shorter duration. They may be used to advantage 

 for the control of DDT-resistant flies and are recommended especially 

 for treatments out of doors and in stables. Some of the organic 

 phosphorus compounds, such as parathion and EPX, are highly 

 toxic to flies, and there is some evidence, based on research by the 

 Universities of California and Illinois, that they are less likely than 

 the chlorinated hydrocarbons to produce resistance. Because they 

 are more toxic to humans and domestic animals, they are not recom- 

 mended for use indoors, but with proper precautions they have been 

 used successfully around garbage dumps and other outdoor situations. 



Chlordane is usually employed in a 2- or 2. 5-percent kerosene 

 solution or emulsion, applied at the rate of 1 gallon to 750 to 1,000 

 square feet to give approximately 100 mg. of chlordane per square 

 foot. Lindane is employed in a solution, emulsion, or suspension 

 at a concentration of 0.5 or 1.0 percent, applied at the rate of 1 gallon 

 to 750 square feet to give a deposit of 25 or 50 mg. per square foot. 

 Chlordane and lindane residual spra}^s are not recommended for 

 complete residual coverage in living quarters. The use of technical 

 BHC should be restricted to situations where the musty odor is not 

 objectionable or there is no danger of contaminating foods. 



Dieldrin is generally recommended for use at the rate of 25 mg. 

 per square foot. This dosage is obtained by applying 1 gallon 

 of a 0.5-percent solution, emulsion, or suspension per 750 square feet. 

 Dieldrin should be used only by experienced operators and under the 

 supervision of responsible officers who will make sure that there will 

 be no hazard to people through food contamination or contact. 



SPACE SPRAYS 



Space sprays and aerosols containing DDT and allethrin, pyreth- 

 rum, or aliphatic thiocyanates are used for immediate control of fly 

 infestations in living quarters, tents, or messrooms. The sprays are 

 dispersed with hand sprayers, portable electric sprayers, or hand- 

 compression sprayers equipped with fine-mist nozzles. The aerosols 

 are dispersed by self-contained propellents from bombs. 



Work was done at the Orlando laboratory on the development of 

 fixed-spray and aerosol equipment for control of flies and other insects 

 in buildings. One spray unit consisted of siphon-type nozzles at- 

 tached to 1 -quart containers, which were suspended below the ceiling 



