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Dealing with Slugs In Your Garden

Posted: April 17, 2012

Hosta damaged by slugs

Hosta damaged by slugs

If you have SLUGS in your garden, you are probably familiar with the damage they cause to your plants. What has gotten me interested in learning more about this pest is the damage they do to my HOSTAS.

Slugs are nocturnal pests, so you don't generally see them. You just start noticing those small holes or the shredded leaves. Soon, the plant becomes completely unsightly. If you look for them at night, you will find that they are about an inch or more long, soft, fat, and very slimy. They are a very destructive pest. They can climb up into shrubs and tall plants, they are very damaging to vegetable gardens, and they love hostas. THEY ARE ESPECIALLY PROLIFIC IN WET YEARS, SO BEWARE IN 2012!

I am an organic gardener, so my first impulse was to check out organic controls. There are many suggestions such as sinking dishes of beer into the garden, (the yeast will lure them in and they will drown in the beer), circling you garden with human hair, crushed egg shells, or Diatomaceous earth, laying boards in the garden during the day, (the slugs will crawl under in the damp coolness, then you scrape them off the board and kill them.) One source even suggested patrolling your garden at night with a flashlight, and picking the slugs off plants with chopsticks! I'm sure all of these remedies work to a certain extent, but in addition to being unsightly and time consuming, they are "closing the barn door after the horse is gone", as the old saying goes. In other words, you are only killing a few adults as opposed to wiping out the eggs and babies.

I started reading more about the life cycle of slugs. I learned that they prefer cool, damp, dark places. They lay their eggs in moist soil, under containers and garden debris, and especially under the debris of the plants they like to eat. Therefore, your first line of defense is to clean debris from your garden, cutting off the hostas immediately after the frost gets them in the fall. If you didn't do that last fall, now would be the time to get it done before those eggs hatch. While you are cleaning up the old leaves, take a small hand-held scratcher, and disturb the earth around the base of the hosta to dislodge any eggs that may be hiding there. You can recognize them when you see a mass of white and, you guessed it, slimy eggs encased in jelly-like mucus.

I, personally, would never use synthetic slug killers because they contain the chemical, Metaldehyde, which causes kidney damage and death to pets and small children. I learned, however, that there is an organic bait, which kills slugs very effectively. The active ingredient in these baits is IRON PHOSPHATE, and the two most highly recommended of these products is SLUGGO and ESCAR-GO. The fact that they contain a bait is very important, because they actually lure the slugs out of their hiding places. When they ingest the iron phosphate, they stop eating immediately, and die quickly, with just enough time to crawl back into hiding so you never have to see them.

Iron Phosphate is an organic product, and is safe for children, pets, fish, and even earthworms. You don' t have to apply it after every rain, like you do the other remedies. In fact, you only need to use it three times a year. When it does break down, it becomes fertilizer for your soil.

In the autumn, after you clean up the garden debris, sprinkle the iron phosphate product on the damp soil of your garden, hopefully killing most of the adults. Then, in March, do another application, followed by a third, one month later. That should take care of most of the young ones who escaped the March application.

One last line of defense is knowing two of Mr. Slug's natural enemies. They would be ducks and snakes. Maybe you would prefer the slugs, but if you live in the country, or beside a lake, consider allowing those ducks to explore your garden. And, I must say, when I gardened on the farm where we had several resident black snakes, I never saw slug damage.

This beautiful Sun Power Hosta is already severely damaged by slugs, and it's only April.

The Penn State Master Gardener Hotline to answer gardening questions is open April through September, on Mondays and Fridays, from 10 am to 2 pm. Call 717-334-6271 or bring in your samples for a diagnosis to 670 Old Harrisburg Rd, Gettysburg.

Barbara Mrgich is a Penn State Extension Consumer Horticulturist from Adams County.  Penn State Cooperative Extension of Adams County is located at 670 Old Harrisburg Road, Suite 204, Gettysburg.  Call 334-6271.