THE PYRETHRINS AND RELATED-COMPOUNDS .40. STRUCTURE-ACTIVITY-RELATIONSHIPS OF PYRETHROIDAL ESTERS WITH ACYCLIC SIDE-CHAINS IN THE ALCOHOL COMPONENT AGAINST RESISTANT STRAINS OF HOUSEFLY (MUSCA-DOMESTICA)

Activities of a range of pyrethroidal esters, incorporating structural variations in all regions of the acid and alcohol components, have be en measured against two fully characterised and homozygous resistant s trains of Musca domestica (kdr and super-kdr). The results, limited in this paper to esters of alcohols with acyclic side chains, show the s ame level of uniform resistance as the kdr strain observed previously, across a range of acid and alcohol variations. Against the super-kdr strain, in contrast to the cyclic side chain set, resistance factors a re barely higher than for the kdr strain. Against super-kdr flies, som e dependence of resistance factor on the position of the side chain su bstituent was detected. Poly-fluorobenzyl esters confer particularly l ow resistance factors.