Something is chewing on my hostas, but I don’t see anything. Any suggestions? MM

There are several insects that could be causing your trouble, but since your problem exists on hostas, I am going to say slugs are responsible for the damage. Slugs seem to love hostas and unless you know what to look for, they can be difficult to find because their primary feeding time is at night. Oftentimes it is the shiny/slimy trails they leave behind that provides the confirming evidence.

Slugs are classified as gastropods making them more like clams and mussels than typical garden pests. They also vary greatly in size from half an inch to more than four inches. Slugs lay clusters of 20 to 100 eggs in moist cracks in the soil or in your garden containers. Within 10 days the eggs hatch and they mature within 3 months to a year.

Young slugs can travel through the soil, eating seeds or roots. As they mature, they venture out at night looking for something to eat and hostas seem like one of their favorite foods.

Slugs have “rasping” mouth parts which means that they tend to scrape away leaf material while eating. Their damage appears in the form of irregularly shaped hole that have smooth edges.

Slugs seek out and thrive in moist environments, so your first line of defense would be to make sure your garden plants have plenty of air circulation. This means perhaps adjusting your watering habits so that you water in the morning rather than evenings. Evening watering leaves the leaves and mulch wet most of the night which will encourage slug activity. Soaker hoses or drip irrigation is also a good solution. It’s also a good idea to inspect any plants you might bring home to your garden for any sign of slugs before planting.

As far as control once you have slugs is concerned, there are several appropriate strategies. First is beer. Not for you but for the slugs. Slugs appear to be attracted to chemicals that are produced by fermenting. Because of this you can place several shallow pans of beer around the damaged plants. The slugs will be attracted to the beer and will become trapped and drown in the beer.

You can also use trap boards or moist newspaper. Place the boards or newspaper near your affected plants in the evening. After a night of feeding the slugs can retreat to the cool, moist environment under the boards and newspaper. In the morning you can retrieve and destroy the slugs.

There are a couple of chemical methods for control as well. These chemicals are called molluscicides. Standard garden insecticides will not be effective on slugs. Metaldehyde is a common molluscicide. However, products containing metalhyde are not approved for use around edible crops and they are quite toxic to dogs so this wouldn’t be our first choice. There are several products that contain iron phosphate that are effective and pose no threat to dogs. The names for these products can be creative, such as Sluggo or even Escar-Go! If you have raised beds or beds in a greenhouse, slugs don’t like copper so you can place strips of copper foil around the legs or edge of your garden bed. Good luck.

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org.

Photo: Gary Bernon, USDA