Milk snail

Systematic position. The milk snail Otala punctata belongs to the phylum Mollusca, class Gastropoda, order Stylommatophora, and family Helicidae. This species is widely recognized as an invasive pest in various parts of the world, known for its significant impact on horticultural and agricultural productivity due to its dietary adaptability.

Biology and life cycle. This species is a hermaphrodite with high reproductive efficiency. Its activity cycle is strictly regulated by environmental humidity. During dry or hot conditions, the snail enters an aestivation period, sealing its shell with a protective epiphragm to retain moisture. Breeding usually occurs during the rainy season, with eggs deposited in moist soil. The population can multiply rapidly under favorable climate conditions, especially in irrigated agricultural zones.

Host plants and damage. Otala punctata is a polyphagous pest, meaning it feeds on a wide range of vegetation. It poses a major threat to vegetable crops (such as lettuce and brassicas), vineyards, orchards, and ornamental gardens. The snail feeds by scraping plant tissues using its radula, which creates irregular holes and skeletonized leaves, often leading to the total destruction of seedlings or damage to fruit surfaces.

Economic impact. The damage caused by these snails goes beyond direct consumption of plant material. Large infestations result in total crop failure and reduced yields. The mucus trails left behind are a significant sanitation issue, making crops aesthetically unappealing and susceptible to secondary fungal or bacterial pathogens, which rapidly degrade the produce after it has been damaged by the snails.

Control measures. Integrated pest management (IPM) is essential for controlling Otala punctata:

• Maintain good field sanitation by removing debris and weeds where snails hide during the day.
• Use physical barriers like copper tape or rough crushed stone to prevent movement into garden beds.
• Deploy bait traps containing beer or specific molluscicide pellets in protected stations.
• Apply environmentally friendly baits based on iron phosphate to control population spikes.
• Hand-pick the snails at night or early morning, particularly after rainy weather, to reduce immediate pressure.