To provide a disease resistance enhancing agent that is effective for controlling diseases of coffee tree.SOLUTION: The diseases of coffee tree are controlled by applying a lysine-containing coffee tree disease resistance enhancing agent to the leaves etc. of coffea tree.SELECTED DRAWING: Figure 1【課題】コーヒーノキの病害の防除に有効な病害抵抗性増強剤を提供する。【解決手段】リジンを含むコーヒーノキの病害抵抗性増強剤をコーヒーノキの葉等に施用することによって、コーヒーノキの病害を防除する。【選択図】図1