123 



Insect Growth Regulators (iGR's) and Qrganophosphorus Larvicides 



Feed-through studies with dimilin and methoprene. Methoprene 

 (Zoecon ' ZR-515 10% tech.) and dimilin (Thompson-Hayward TH 6040 25% 

 tech.) were added to poultry feed to produce diets of the following 

 concentrat ions : 



!GR 



TH 6040 

 TH 6040 

 ZR-5<5 

 ZR-515 



Amount added to 



136.4 kg of basal 



layer diet(g) 



Concentration 



of treatment 



diet (ppm) 



5.44 



0.54 



13.60 



1.36 



10 

 1 



10 

 1 



Diets were fed to treatment groups of 44 week-old Babcock B-300 laying 

 hens randomized in range houses measuring 2.4 by 4.6 m (Figure 26). The 

 10-ppm diets were fed for 107 days after which the 1-ppm diets were fed 

 for 14 days. One week elapsed between the change of IGR treatment 

 level s. 



Manure was bioassayed three times while 10-ppm diets were fed, and 

 twice while 1-ppm diets were being fed. Samples were seeded with eggs 

 of M. domestica. Pupal traps were set twice while the 10-ppm diets 

 were being fed. 



Resul ts. Feed consumption of hens fed methoprene and dimilin is 

 shown in Table 20. At both dietary levels, birds eating the dimilin 

 diets consumed feed in amounts that were significantly greater than 

 those consumed by birds in the control groups. Birds eating methoprene 

 diets consumed less feed that the birds in their respective control 

 groups, but the differences were not significant. 



During sampling period 9 (Table 20), hens were inadvertently 

 allowed to run out of feed, which accounts for the consumption level of 

 only 77.18 g/bird per day. 



