Snails are omnivorous and have many hosts, which not only harm green leafy vegetables, but also harm many vegetables and crops such as Cruciferae, Solanaceae, Leguminosae and Cucurbitaceae. Both seedlings and adult plants will be hurt. Snails only eat mesophyll when they are young and leave the epidermis; Older individuals scrape the leaves and stems of plants with their tongues, grind them into small holes or even gnaw off the stems, or the leaves are shapeless, notched, or have residual veins, which can cause seedling shortage and broken ridges in severe cases.