Which statement best describes a protectant?

A protectant is primarily designed to create a barrier or defense against potential threats such as diseases or pests, thereby helping to prevent pathogen establishment. These products are typically applied to plants or surfaces to inhibit the growth and development of pathogens before they can infect the host. By using a protectant, you increase the likelihood of plant health and resilience because the plant is better equipped to fend off disease attacks.

The other options describe functions that are not characteristic of a protectant. For example, some pesticides may indeed kill pests on contact, but that falls under a different category of pesticide action known as "contact insecticides." Promoting plant growth relates more to fertilizers or growth regulators rather than protectants. Enhancing soil quality focuses on soil amendments or practices that improve soil health, which is unrelated to the specific action of protectants. Therefore, the choice regarding preventing pathogen establishment aligns perfectly with the definition and purpose of protectants in pest management.