Synergy of cymoxanil and mancozeb when used to control potato late blight

Summary Synergism between fungicides could be used to reduce the application dosage. Synergism between cymoxanil and mancozeb was studied using potted potato plants under field conditions. In three experiments the preventive efficacy of the fungicides and fungicide mixtures in the treatments were studied using a bio-assay. Potato plants were sprayed with the fungicides or fungicide mixtures. Leaves were picked from the potato plants with regular intervals after fungicide application. The efficacy of the fungicides was studied in a bioassay by inoculating the leaves withPhytophthora infestans zoosporangia. The Abbot method was used to show synergistic effects of the cymoxanil/mancozeb mixtures tested. In two of three experiments synergy of the fungicide mixtures was found.