253 



Parasitism rates of pupal parasites have been shown to double in 

 manure treated with methoprene (Butler and Greer, 197M, due to the 

 action of methoprene that prevents pupae from emerging. Used for spot 

 treat i ng, methoprene could be applied at rates high enough to affect 

 larval molts as well as the pupal molt. Other investigators found 

 methoprene to be ineffective as a topical larvicide in poultry manure 

 (Morgan et al . , 1975) . 



Laboratory Studies with CGA 72662 



At high concentrations, CGA 72662 kills the early instars of fly 

 larvae. Only H. illucens and F. can-iaularis formed pupae at the initial 

 levels of CGA 72662 tested, and none of these pupae emerged (Table 27). 



An LCj-p. of 0.45 ppm was found for house fly larvae. Although 

 this is well below 1 ppm, the slope of the dosage-mortality curve indi- 

 cates that the susceptibility of the house fly population tested to 

 CGA 72662 is relatively heterogeneous (Hoskins and Gordon, 1956). 



CGA 72662 concentrations of 0.25 ppm produced larviform pupae that 

 eclosed like normal pupae. As concentrations continued to increase, 

 numbers of larviform pupae increased, and the number of uneclosed 

 larviform pupae increased (Table 28). At 1.0 ppm five uneclosed larvi- 

 form pupae formed in the four treatment replications and no other larvae 

 or pupae were found. This indicates that at concentrations of 1.0 ppm 

 and above, larvae were being killed prior to reaching the pupal stage. 



CGA 72662, Dimethoate, Dichlorvos, and Revap 

 as Topically Applied Larvicides 



Effective larval control lasted for 7 days with Ravap and di- 

 methoate, and from 7 to 1 1 days with dichlorvos. Seven days of control 



