19 



10 g/ton of feed. Good larval control was achieved, but inability to 

 produce total control was blamed on migration of adult flies. Morgan 

 et al. (1975) found that methoprene in chicken feed at 0.0005 and 0.01% 

 produced mortalities of 70.9 and 99.3%, respectively,, and had no effects 

 on the hens' weight. Methoprene was not effective, however, when 

 poultry manure was treated topically in the field. 

 Dimi 1 in 



Dimilin, also known as TH-6040 and d i f 1 ubenzuron , has been classi- 

 fied as an inhibitor of chitin synthesis. Many analogues of dimilin 

 have been synthesized and tested, but none are as effective as difluben- 

 zuron itself (DeMilo et al., 1978). In the larval stages, dimilin 

 causes rupture of larval cuticle during or shortly before the next molt 

 (Jacob, 1973). Topical application to Dupae can affect emergence of 

 adults (Cerf and Georghiou, 197*0. Application of dimilin to house fiy 

 adults can result in the suppressed hatchability of eggs laid long after 

 the application date (Wright and Spates, 1976). 



Even though dimilin was active against all major nontarget insects 

 in bovine fecal pats (Pickens and Miller, 1975), poultry farms treated 

 topically with dimilin had greater parasitoid populations and species 

 variety than did farms treated with dimethoate (Abies et al., 1975). 

 When dimilin was fed to chickens at 6.2 to 12.5 ppm, fly control of 

 100% was achieved, but residues were found in all eggs sampled (Miller 

 et al., 1975). 

 Resistance to IGR's 



House fly resistance has been demonstrated for both methoprene and 

 dimilin (Plapp and Vinson, 1973; Oppenoorth and Van Der Pas, 1 S77 ; 

 Georghiou et al., 1978). 



