A survey methodology for assessing yield potential and coffee berry losses in peasant coffee
Browning, G.; Dorward, A.
Experimental Agriculture 25(2): 235-242
ISSN/ISBN: 0014-4797 DOI: 10.1017/s0014479700016732
The effects of coffee berry disease (CBD) [caused by Colletotrichium coffeanum] on yield are usually estimated by counting infected berries on marked branches throughout fruit development. This method is impractical when surveys are required of yield losses over large areas of extensively cultivated peasant coffee. A survey method is described for estimating yield potentials and the loss in yields due to severe CBD infection under such conditions. The method exploits the relation between numbers of flower nodes and yiled per tree, and requires a single subjective estimate of disease incidence of young expanding berries. Yield losses are estimated from the changes in this relation resulting from berry infection. Results are presented for peasant coffee at different stages of rehabilitation in Ethiopia. They indicate that the method is suitable for estimating production in agronomic improvment projects and for identifying areas where CBD incidence might economically justify fungicide spraying.