Pesticide Resistant Flies

The Central Science Laboratory and Pesticides Safety Directorate of the Ministry of Agriculture Fisheries and Food (MAFF) have issued an advisory leaflet on pesticide-resistant houseflies. The resistance is to pyrethroids, particularly residual formulations, which have been sprayed onto animal house walls in an attempt to kill flies which land on them.
    MAFF advises that residual pyrethroids should not be used, and space treatments containing pyrethroids or pyrethrins should not be used continuously. Instead, MAFF advises using pyrethroid space sprays no more than once weekly, and if more frequent treatments are required other products should be used.
    The leaflet makes no mention of products such as insect growth regulators. Panic over resistance may thus cause a regression in pesticide use patterns rather than a progression to more modern methods.

Pesticide-resistant house flies in animal houses, PSD and CSL MAFF leaflet, January 1994.

[This article first appeared in Pesticides News No. 24, June 1994, page 17]