Pest
Slugs and snails
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Watch for | Watch for in February | Watch for in March | Watch for in April | Watch for in May | Watch for in June | Watch for in July | Watch for in August | Watch for in September | Watch for in October | Watch for in November |
What it is
Slugs and snails are molluscs that graze on living and decaying plant material. In a damp maritime climate they are the commonest garden complaint of all. The garden snail, the grey field slug and several large roundback slugs do most of the harm, while keeled slugs live mainly underground. Many other species feed chiefly on rotting matter and do little damage.
Symptoms
Irregular holes with smooth edges appear in leaves, petals and stems, often overnight. Seedlings may vanish entirely, leaving only a stump. Silvery slime trails on soil, paths and pots confirm the culprits. Potato tubers develop small entry holes leading to hollow cavities, and strawberries are scooped out from below. Caterpillar damage looks similar, but you will usually find droppings rather than slime.
Cause
Slugs and snails feed mostly at night and on mild, wet days, sheltering by day under pots, boards, stones and dense plants. They lay clusters of pearly eggs in damp soil and can breed in almost any month when it is not frozen. Spring and autumn are peak times for damage.
Control
Go out with a torch an hour after dark, especially after rain, and collect them by hand. Lay boards or upturned grapefruit halves as daytime traps and empty them each morning. A beer trap sunk slightly proud of the soil catches slugs without drowning beetles. In warm, moist soil in spring and autumn, a watered-in nematode treatment targets slugs below ground. Copper tape around pots and wool or bran mulches give some protection. Use slug pellets only as a last resort, sparingly, and follow the label.
Prevention
Grow seedlings on in modules until they are tough enough to survive a nibble. Water in the morning so the surface is dry by nightfall. Encourage hedgehogs, toads, frogs, thrushes and ground beetles with a small pond and log piles. Choose tougher plants for slug hotspots, such as thick-leaved hostas, and clear rubbish near vulnerable beds.
Plants often affected
Could it be something else?
These problems share some of the same symptoms. Compare them, or run the symptom checker with these signs ticked.
Months to keep an eye out: February, March, April, May, June, July, August, September, October and November.
Sources
Identification and life-cycle details were checked against the references below. Text and advice are our own. See our editorial policy.