Effect of passages on development of carbendazim resistance in Alternaria alternata causing leaf spot of gerbera

Culturing of the sensitive Alternaria alternat aisolate on carbendazim continuously for eight successive passages significantly increased resistance. Use of carbendazim alternately with mancozeb, roko and kocide reduced the resistance. When carbendazim was used in combination with mancozeb, roko and kocide,there was complete inhibition of the pathogen at the first passage only.