ABSTRACT
The Muscidae flies are known to act as carriers of several important diseases of poultry. Furthermore, the poultry house can also act as breeding site of this nuisance, and cause serious public health difficulties to the neighbours. Recently the annual cost of house flies control has been estimated over 13 cent per hen in USA. Insect-growth regulator substances can be substituted as insecticides to inhibit life cycle of flies larvae. In the past, such substance was introduced as granul to scatter over the manure but, today it is recommended as a feed additive. In the present study the effect of cyromazine at the level of 500 g/ton of feed was evaluated against the house fly in a caged-layer house. The monitoring white card was used to compare the population of the flies either in the treated or untreated poultry houses. The results indicated that the efficacy rate of cyromazin against house fly was 56.5% and 92.4% within 3rd and 4th week of post treatment respectively. No side effect was observed on appetite and production rate of poultry during this study