AbstractA series of novel pyrethroids containing a benzothiazole ring which replaces the phenoxy substituent in the benzyl ester portion have been synthesised. The compounds prepared were from four types of acid substituent, and were screened for acaricidal activity against Tetranychus viennenist, Zacher. Several compounds showed good activity at 250 mg litre−1. As expected, it was found that the highest activity was associated with substitution at the 3‐position of the benzyl ring. A fluoro‐or trifluoromethyl‐substituent in the benzothiazole ring usually enhanced potency. α‐Cyano substitution also increased activity.