Which type of fungicides can control fungi already present within a plant?

Systemic fungicides are designed to be absorbed by the plant and translocated throughout its tissues. This allows them to control fungal infections that are already present inside the plant, addressing issues that have penetrated beyond the surface. While protectant fungicides create a barrier to prevent fungal growth and contact fungicides act on the external surface of the plant where they are applied, systemic fungicides are specifically formulated to penetrate the plant’s vascular system. This mode of action enables them to reach and eliminate fungi that have invaded the plant tissue, making them effective for treating existing infections rather than merely preventing new ones. Organic fungicides and their modes of action can vary widely, but they do not inherently imply the same level of systemic action as those specifically classified as systemic fungicides.