[The effect of dimethoate selection on trichlorfon and dimethoate sensitivity in Musca domestica]

Selecting of strain a Musca domestica resistant to trichlorphon with Bi 58 (active ingredient: dimethoate) resulted in an only slight (1.33-fold) increase of the resistance to dimethoate between 1974 and 1975. In the same time the resistance to trichlorphon rose to 5.28 times the original degree. The resistance extends to some other organophosphates, especially malathion, dichlorvos and bromophos, but not to diazinon. Among the insecticides registered for control of flies in pig-sties Bi 58 has the greatest chance, though there exists neither a certainty for the decrease of the resistance to trichlorphon nor for the non-appearance of a resistance to dimethoate. To overcome the problem of flies in stables and sties, particularly in plants of industrial cattle-breeding, complex measures must be taken.