Data are presented on research in Kenya in 1964 - 1969 on anatomical, mycological, epidemiological, chemical control and cultural aspects of coffee berry disease, Colletotrichum coffeanum Noack, of Coffea arabica L. The pathogen causes flower and berry losses and was found in branches where it occupied clearly defined areas of the cortex just before or after formation of the first phellogen. Saprophytic Colletotrichum spp. inhabit bark areas with more periderms in the cortex. No relationship could be found in Kenya between Glomerella cingulata (Stonem.) Sp. & Schr., the perfect stage of most of the saprophytic Colletotrichum bark components, and C. coffeanum . The seasonal fluctuations in pathogenicity in the bark population of C. coffeanum could be assessed and compared with the total sporulating capacity of the bark population of all Colletotrichum spp. Formerly the level of this total sporulating capacity, or 'inoculum potential' as it was then called, was used as an indication when pre-rain copper sprays had to be applied and how effectively the fungicide had reduced the bark inoculum. Based on these data the recommendations for chemical control were changed from pre-rain fungicide applications, to a spraying regime well into the rainy period, the accent being on protection of the berries rather than on a reduction of the bark inoculum. The fungicide Ortho Difolatan proved to be more effective than copper based compounds. Cultural practices, like the application of high levels of fertilizers, manure and mulch and rigid pruning practices, had no effect on the level of C. coffeanum in branches. Copper containing fungicides pushed the Colletotrichum balance in favour of C. coffeanum . Berries from non-copper sprayed coffee fields were less susceptible to standard conidial suspensions of C. coffeanum than berries from copper sprayed trees. A similar effect of fungicides should be considered in South and Central American coffee growing countries, where the application of fungicides has increased tremendously since the occurrence of Hemileia vastatrix Berk. et Br. in Brazil.
|Qualification||Doctor of Philosophy|
|Award date||28 Feb 1979|
|Place of Publication||Wageningen|
|Publication status||Published - 1979|
- plant pathogenic fungi