Ecological factors influencing incidence and severity of Coffee Leaf Rust and Coffee Berry Disease in major Arabica coffee growing districts of Uganda

Abstract

Coffee Leaf Rust and Coffee Berry Disease are the most devastating diseases of Arabica coffee in Africa. The importance of coffee in economies of many African countries like Uganda, presents urgent need for cost-effective disease control strategies. In this study, 192 coffee farms were surveyed and their corresponding incidence and severity recorded. Nebbi district had the highest CLR incidence (90.2%) and severity (2.2%) followed by Sironko (67.9% and 1.9%) and least in Kapchorwa (20.4% and 1.3%) respectively. CBD incidence was highest in Kapchorwa (6.0%) followed by Nebbi (1.7%).There was no CBD incidence observed in Sironko. There was a significant (pd”0.05) interaction between altitude and disease severity. Thin and medium shade intensity had highest CLR incidence followed by thick and no-shade levels. CLR was highest in farms under mono-shade followed by farms under mixed-shade and least in open-farms. CLR severity was found to be highest at very steep slopes and medium slopes and least on gentle slopes. In conclusion, CLR was present in all surveyed districts while CBDoccurred in Kapchorwa and Nebbi districts at intensity levels enough to trigger economic losses.