Fungicidal Control of Plant Diseases in Malawi

Abstract Fungicidal spraying experiments carried out in a number of crops in Malawi are described. Bordeaux mixture (4 : 4 : 50) sprays applied after every 2 in. cumulative rainfall during the wet season to tomatoes gave the most economical control of late blight. Isariopsis griseola leafspot on beans was best controlled by Zineb applied weekly. Large groundnut yield increases follow fortnightly applications of copper and sulphur fungicides but these were uneconomical except on one variety. Worthwhile control of late blight on potatoes was achieved by shaking a cuprous oxide fungicide by hand from a hessian sack on to the crop four times during the growing season. Copper oxychloride applied at two-monthly intervals. to coffee controlled Cercospora coffeicola berry disease very cheaply.