Abstract
Bean rust (Uromyces appendiculatus) was generally controlled with both contact and systemic fungicides on three cultivars (Blanca del País, Bountiful and Naranjito) tested at two locations in Puerto Rico. However, effectiveness varied with rate, cultivar, location and disease level. On cultivars in Lajas, contact fungicides chlorothalonil and mancozeb were more effective in reducing disease symptoms and in increasing yields than the systemic fungicides oxycarboxin and triforine. There were fewer differences between fungicides in Isabela, where disease incidence was lower, but contact fungicides again were generally more effective. Mancozeb was the most effective fungicide, reducing disease symptoms and increasing yields. Certain fungicides combined with genetic resistance should be effective in increasing bean yields.