Controlling Slugs

A wet and shady site and a hosta with thin leaves (low substance) is a great target for the evil slug. Even small slugs can cause big damage.

A wet and shady site and a hosta with thin leaves (low substance) is a great target for the evil slug. Even small slugs can cause big damage.

I’ve grown hostas and other shade plants for many years, and slugs are just about the only pest that ever bothers them.  Controlling slugs is not a very appetizing task (unless you have a duck on the premises…they find them appetizing).  The tell tale damage from slugs are holes in the leaves.  They don’t chew from the edges, there will be holes in the leaves themselves.

Slugs like this can really damage a garden, particularly a moist shade garden.

Slugs like this can really damage a garden, particularly a moist shade garden.

Controlling slugs is most directly accomplished by the use of slug bait sold at hardware and chemical supply stores.   The quality varies.  Some are in an oatmeal like bait just seem to make a mess on the plants and it takes way too much of it to do any good (Corry’s).  Commercial bait available locally is sold as Lockout, but only in 40 lb bags for about $60 at Wilbur Ellis.  Most slug bait has the same active ingredient, metaldehyde.

Sluggo is among the safest of the slug baits being pet safe-it contains no metaldehyde.  I used Deadline in various forms before I had the nursery and my pets left it alone.  The commercial baits (Deadline Bullets, Lockout) are sold in much larger bags, but you can use less product to control the problem.  The bait is better so you apply less metaldehyde and kill more slugs/snails with the commercial variety.  Metaldehyde is the main  “non-safe” active ingredient used, and its effectiveness depends on the bait with which it is mixed.

The most effective nonchemical method for controlling slugs is pretty easy if you subscribe to the newspaper or newspapers.   Just soak a newspaper section and lay it down by the plants at dusk.   Really soak it.   In the morning, go pick up the paper and slugs will be attached to the underside.  Fold and discard and repeat until control achieved.   Slugs can travel over 100’ in a day, up to 100 yards, so if they have a breeding spot at the next door neighbor’s home, you will get them again.  Looks a bit strange to see 10 or 20 sections of wet newspaper in the garden, but if you put it on at dusk and remove in early morning, who knew?

Odd methods like saucers of beer or copper bands around beds or diatomaceous earth have not proven to be useful.   I was in a hosta growers group, a group of professional nurseries with lots of hostas.  We found all those rather ineffective. Of course, the practice of a child putting salt on a slug is less humane that just stepping on it and salt ruins your soil for your plants.  These are simply useless avenues for the long run.

If it is early in the season and you see a hole like this appear, you can treat for slugs and prevent really obvious damage. Since they come at night, you often won't actually encounter the slugs until it is too late.

If it is early in the season and you see a hole like this appear, you can treat for slugs and prevent really obvious damage. Since they come at night, you often won’t actually encounter the slugs until it is too late.

A thick leaf (good substance as we call it) will be less tasty to a slug and may be skipped. Consider having a percentage of large hostas with thicker leaves.

A thick leaf (good substance as we call it) will be less tasty to a slug and may be skipped. Consider having a percentage of large hostas with thicker leaves.

It’s illegal to sell portions of controlled pesticides, so we can’t help you with a smaller portion.    The particulars of various slug baits and the risk to pets and so forth can be gained by reviewing the product labels and the MSDS sheet for the product.  The store selling the product will have information, especially if you go to Wilbur Ellis for the commercial product.  Always follow label directions and use the safety measures required by the product label.  I offer this information not as a company expert on various pesticides, but as a long term hosta grower who has decades of experience controlling slugs.

So if you grow plants that are suffering from slug damage, there is hope for control.  Those holes will be there for the entire season, and fresh leaves will emerge next spring.  Just be sure to treat early enough in the year so the slugs never get the chance to wreck the appearance of the plants.  Happy Gardening!