Experts have predicted that the Spanish Arion vulgaris have been mating with British slugs to create ‘superslugs’ – which can reportedly survive hot and cold weather conditions and are difficult to eradicate through traditional means – while predators, such as hedgehogs, are also less likely to pursue these hybrid varieties due to the amount of slime they produce.
Lloyd Taylor, Head of Garden at Wilko, commented: “While Spanish slugs have made recent headlines, billions of slugs of all varieties were expected to descend upon British gardens this year following our unusually mild winter. The steady sales increase we have seen shows our customers are becoming increasingly aware of this garden menace and are taking steps to protect their plants.”
Plants and deterrents
There are plants which slugs don't like, including aquilegias, geraniums and foxgloves, which have high toxin levels.
Deterrents include putting copper tape around plant pots, placing sharp sand or crushed eggshells around plants, or even building a pond or water feature which will attract toads, frogs and newts - all natural predators to the slug.
Some people recommend boiling up cloves of garlic, straining off the liquid and watering around plants with that. Other than that, it's a case of continuing with dawn and dusk patrols to pick the slugs off.
While many people opt for slug pellets, Hetherington claims that even so-called organic varieties may harm other wildlife.
Guy Barter, RHS chief horticultural adviser, says nematodes are probably the most eco-friendly solution. Parasitic nematodes occur naturally in the soil, but not in numbers high enough to see off the sheer numbers of pests. Fortunately, they can be bought from online garden retailers: the organisms are mixed with water and then watered into the ground. Some specifically target slugs, infecting them with bacteria.
"They are an excellent idea because they have no effect on non-targeted organisms, are safe for the user and are organic. The only downside is that they are rather expensive," Barter says.
However, Hetherington points to research that has shown cases of certain nematodes crossing species, infecting bees as well, so would recommend using them only as a last resort.
If, during your slug patrols, you come across any large leopard slugs - so-called for their distinctive spotted markings - it might be better to leave them alone, as they are carnivorous and will eat other slugs.
How do you prevent slugs in your garden? Let us know in the Comments section below.