Alternaria spp., Fuser/um spp. and Helminthospodum spp. were found to be the essential fungi causing black rot on cotton plant. Under laboratory conditions, it had been found that Alternaria spp. had high tolerance to fungicides namely propineb, cuproxate, mancozeb, metalax­yl-mancozeb and s-harts more than the other two fungi. Alternaria spp., was chosen as an experimental fungus. The effects of metalaxyl­mancozeb and propineb on the fungus were the best, followed by man­cozeb and s-haris, while cuproxate failed to inhihbite the spore germina­tion at the field recommended rate (FRR). Insecticides: cyfluthrin. prole­nolos, cypermethrin, deltamethrin, methomyl-dimilin, chlorpyrifos, tiodicarb, fenpropathrin and fenvalerate. had no/or neglected effect on the fungus Alternaria spp. on the basis of LC50 values. Mixing these in­secticides with the above fungicides gave best results in case of manco­zeb, s.haris and metalaxyl-mancozeb, respectively, while in case of pro­pineb the effeciency was reduced.