Abstract:
To evaluate the effective impact of Coffee Berry Disease (CBD) on berry loss in the smallholder context of
SW Ethiopia, CBD symptoms were monitored during the rainy seasons of two consecutive years on both
protected (with fungicide applications) and unprotected coffee branches. Fungicide applications (mancozeb) had significant effect (P < 4e-05) on the proportion of necrotic and dropped berries; CBD necrotic
symptom was reduced from 48.7% (non treated) to zero (treated) while berry drop was reduced from
52.8% (non treated) to 40.8% (treated), suggesting that only 12.1% of the observed berry loss could
certainly be attributed to CBD. Disease incidence was not influenced by the branch position in the canopy
of the monitored trees. Altitude was an important factor controlling the disease incidence as it favored
the development of both necrotic and drop symptoms. The result suggests that non-CBD factors controlling the physiology of berry production, such as plant age, pruning or soil fertilization, climate are
predominant in the studied context to explain yield loss, and that berry drop symptom assessment alone
may lead to an overestimation of CBD impact.
