20 



Chemical larvicides 



The use of chemical pesticides started about the same time the 

 poultry industry began keeping chickens in cages (Hartman, 1953). The 

 following is a brief review of chemicals that have been used as larvi- 

 cides in poultry manure and their efficacy at the time they were tested. 

 For a more complete review of larvicides, see Miller (1970). 



The idea of oral larvicides evolved in the late 1920's. Cows were 

 fed tannic acid, linseed oil, Mg 2 SG\, and NaCl as possible controls for 

 horn f 1 ies (Mi 1 ler, 1970) . 



Wolfenbarger and Hoffmann {\3kk) may have been the first to advocate 

 the use of DDT as a nouse fiy larvicide on poultry farms. An emulsion 

 of 0.25% DDT applied to manure at 1.9 1/9-3 m 2 gave good house fly 

 control, but soldier flies, Hermetia itlucens, were fairly tolerant 

 (Tanada et al . , 1950) . 



A 1% solution of malathion EC applied at 3.8 1/9-3 m 2 controlled 

 fly larvae after two applications 5 days apart. Adults resting on 

 manure were also killed (Mayeux, 195^a). Malathion was more toxic to 

 predatory mites than to house fly larvae (Axtell, 1966). 



Diazinon applied as a liquid and as a dust controlled fly larvae 

 for 1.5 to 2 weeks, but fly resurgence occurred after 2 weeks (Wilson 

 and Gahan, 1957). Wicht, Jr. and Rodruguez ( 1 970) achieved good control 

 with diazinon and claimed little damage was done to predatory mite 

 populations. Axteli 1,1966), however, reported that diazinon is just as 



toxic to mites as it is to flies. 



TM 

 Dichlorvos, 20% Shell Vapcna resin strips ground up, gave good 



control of house fly larvae and adults for about 7 weeks with three 



