Milk snail

The milk snail (Otala lactea) is a terrestrial gastropod mollusk in the family Helicidae. Native to the Mediterranean region, it has become a significant invasive pest in many parts of the world. Its ability to adapt to diverse climates and its high reproductive rate make it a challenging adversary for gardeners and professional farmers alike.

This species is highly polyphagous, meaning it feeds on a wide variety of plant species. Its preferred hosts include vegetable crops like lettuce, cabbage, and beans, as well as various fruits, particularly strawberries. It also causes substantial damage in ornamental gardens by consuming foliage and tender shoots of flowers, often destroying young seedlings entirely.

The biology of Otala lactea is characterized by a strong dependence on environmental moisture. During dry seasons, these snails enter estivation, sealing their shells with a calcareous epiphragm and attaching themselves to vertical surfaces such as tree trunks or fence posts. They emerge during periods of high humidity or rainfall to feed and mate, completing their life cycle rapidly in ideal conditions.

Feeding damage is characterized by large, irregular holes in plant tissues. The snails often consume entire leaves, leaving only veins, and bore into fruits, which creates entry points for secondary pathogens like fungi and bacteria. In severe infestations, the presence of snail mucus and droppings can further reduce the market quality and shelf-life of harvested produce.

Effective management requires an integrated approach. Cultural controls include removing debris and dense vegetation where snails hide during the day and reducing irrigation levels to dry out the soil surface. Physical barriers, such as copper tape or abrasive mulch, can protect sensitive plants. Chemical control via molluscicides (e.g., iron phosphate baits) is effective if applied correctly during peak periods of snail activity.