Effectiveness of new fungicides against coffee berry disease (Colletotrichum coffeanum) in Kenya

A field trial to determine the biological efficacy of five new fungicides and one fungicide combinations against Coffee Berry Disease (CBD) was carried out for three years at Kiamumbi Estate, Shirlan (fluazinum 500 g/l) was found to be consistently effective against Colletotrichum coffeanum at the rates of 0.1 and 0.2 per cent formulated product and has been recommended for control of CBD in Kenya at the lower rate. Octave Super (formulated mixture of Prochloraz-Mn and Copper) and a tank mixture of Octave (Prochloraz-Mn) and Copper were found to reduce CBD with resultant yield increases during the year with high disease incidence. the two have also been recommended for CBD control in Kenya. The other new treatments were not consistent in their performance (disease control and yield) and have been withdrawn from further tests by the parent manufacturers. Variations in disease development during the period of testing could, to a large extent, be explained by the rainfall intensity and distribution which also affected the cropping patterns of the trees. The possible interactions between weather, disease development and the effects of the fungicide treatments are discussed.