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Slugs and Snails: how to recognise and treat it

Pest

Slugs and Snails — Photo: Schlaghecken Josef, CC BY-SA 4.0, Wikimedia Commons

Symptoms

Irregular holes with smooth edges in soft leaves, flowers and low-hanging fruit such as strawberries and tomatoes.
Shiny, silvery slime trails on leaves, soil, pots or glass; the damage happens at night.
Seedlings and young shoots eaten down or cut off at soil level.
Holes and tunnels in potatoes and other tubers, made by slugs that live in the soil.

Organic treatment

Search by torchlight on mild, damp evenings and hand-pick slugs and snails into a container.
Sink jars part-filled with beer into the soil, or lay half orange, grapefruit or melon skins cut side down near vulnerable plants; empty them every morning.
Water the nematode Phasmarhabditis hermaphrodita into moist soil at 5–20 °C, in spring to early autumn; it kills slugs but rarely reaches snails.
Protect young transplants with cloches.

Chemical treatment

Iron phosphate (ferric phosphate) bait, scattered thinly in the evening after watering; it is safer for pets and wildlife than metaldehyde, but the RHS advises against any slug pellets, even organic ones, because of their effect on wildlife — follow the label.

Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.

Prevention

Remove daytime hiding places near vulnerable beds — boards, stones, debris, weeds and dense ground cover.
Water in the early morning or use drip irrigation, so the ground is drier at night.
Encourage predators such as birds, frogs, toads, hedgehogs, slow-worms and ground beetles.
Plant sturdy pot-grown plants instead of small seedlings, and choose plants slugs like less where damage keeps recurring.

Sources

Figures checked against these sources.