What is the term for a chemical layer that protects a plant from pathogens?

The term that describes a chemical layer specifically designed to protect a plant from pathogens is referred to as a protectant. Protectants serve as a barrier that prevents the establishment and spread of various diseases caused by fungi, bacteria, and viruses. They may function by creating a physical or chemical shield on the plant's surface, reducing the likelihood of pathogen infection.

In contrast, fungicides, insecticides, and herbicides have more specialized functions. Fungicides are specifically designed to combat fungal infections, while insecticides target pests such as insects. Herbicides, on the other hand, are used to control unwanted plants or weeds. Each of these chemicals addresses different aspects of plant protection, which distinguishes protectants as a broad term for any substance that offers a defensive barrier against plant pathogens.