Effect of Artificial Shading on Severity of Coffee Berry Disease in Kiambu County, Kenya

Abstract

Coffee Berry Disease (CBD), caused by the fungus Colletotrichum kahawae, is a major constraint that hinders Arabica coffee production in Kenya. The disease causes up to 80% coffee losses thus affecting export earnings and food security in Kenya. Colletotricum kahawae is spread by raindrop splashes on unprotected trees and excessive wetness in the coffee bush. This study assessed the specific effect of artificial shading on the development and progression of C. kahawae in a commercial farm in Riabai area of Kiambu County in Kenya. The study was formulated out of the realization that the commonly used fungicides for protecting the crop were expensive and hazardous to the environment. International legislation on chemical residue levels is also becoming stringent in most coffee consuming countries. The experiment was laid out in a three replicate Randomized Complete Block Design. There were four treatments comprising of (i) four pruned and artificially shaded coffee trees; (ii) four shaded and unpruned trees; (iii) four pruned and unshaded trees and (iv) four unpruned and unshaded trees. Data was recorded on diseased berries, losses due to physiologic fall and total losses due to both and expressed as percentage of the total berries. The data was subjected to Analysis of Variance (ANOVA) using general linear model (GLM) on COSTAT software. Treatment means were separated using Duncan’s Multiple Range Test at P≤0.05. The results showed that artificial shade significantly reduced development and progression of CBD. The major finding of this study is that shade is an important cultural practice in the management of CBD. It is recommended that growing coffee under agroforestry system where artificial shade is substituted with shade trees will be more beneficial to the small holder farmer.