Of the two types of fungicides, what is the function of protectants?

Protectant fungicides function by creating a barrier that prevents fungal pathogens from infecting plant tissues. Unlike curative fungicides that aim to treat existing infections, protectants are applied proactively to shield plants from potential diseases before they occur. This preventive approach is essential in managing and controlling fungal diseases, particularly in agricultural settings where maintaining crop health is crucial. Protectants are often applied to plant surfaces, forming a protective layer that inhibits the germination of fungal spores and their ability to penetrate plant tissues, thus significantly reducing the likelihood of disease development.

In this context, other choices do not align with the primary role of protectants: they do not cure existing plant diseases, they do not assist in insect control, nor do they promote plant growth directly. Their main purpose is explicitly to prevent diseases, making this answer specifically focused and accurate within the scope of fungicides' functions.