In 2‐year field trials with three different copper formulations it was observed that the incidence of bacterial blight of coffee decreased in response to increasing amounts of copper in sprays. However, reduction of disease achieved by the sprays was not in proportion to the amount of copper in each formulation. Similar sprays of each of the three formulations achieved different levels of blight reduction in different sites. The sprays became less effective as bacterial blight infection pressure increased. The dual effect of these sprays on the control of coffee berry disease was also limited by the copper content in the sprays. The interaction of copper formulation, dosage and site factors in the control of bacterial blight, coffee berry disease and yield response are discussed.