Naptalam is primarily used as a selective herbicide, especially in the control of broadleaf weeds and grasses in crops such as onions, garlic, and certain ornamental plants. It is commonly applied pre-emergence to prevent weed seed germination, making it effective in maintaining clean cultivation beds during early crop development. One of its major historical uses was in nurseries and on conifer seedlings to manage unwanted vegetation without harming the main crop when used at proper rates. Due to its activity as a plant growth inhibitor, it has also been used to suppress sucker growth on tobacco plants. However, its use has declined in many regions due to environmental and health concerns, leading to regulatory restrictions.