Crude extracts of Ajuga nippcmensis possessed antifeedam and growth regulation effects onthe larvae of the diamondback moth. Chloroform extract was the most effective. Symptoms including slowly appearing prolapse of the anus, blackening of the body wall. and malformation of larvae or prepupae; the reproduction process was also affected which might help inhibit the increase of the population in the field. An insecticide resistant strain of diamondback moth showed no resistance to the extract of Ajuga nippanensis. The authors suggest that applications of extracts of this plant would be a new method for the management of diamondback moth resistance.