What term describes a fungicide that penetrates the outer layers of a plant but does not circulate throughout the entire plant?

The term that accurately describes a fungicide that penetrates the outer layers of a plant but does not circulate throughout is "local penetrant." This type of fungicide is designed to move into the plant's tissues enough to provide localized protection against fungal infections, yet it lacks the ability to spread throughout the entire plant system.

Local penetrants are beneficial in managing diseases on the surface of the plant or on tissues just beneath the outer layers. Compared to systemic fungicides, which can be absorbed and transported through the plant’s vascular system, local penetrants focus on specific areas, making them effective for localized treatment without affecting the entire plant.

It’s important to distinguish this from contact fungicides, which remain on the surface of the plant and do not penetrate at all, or systemic fungicides that are fully absorbed and distributed throughout the plant. Curative fungicides typically refer to products designed to treat existing infections rather than solely prevent them, further establishing local penetrant as the most fitting choice for the definition provided.