I love my hostas, but something is chewing on them. Suggestions? AG

While there are several options for what is chewing on your hostas, I am going to guess the culprit is a slug. Slugs typically are most active at night so it’s easy to miss these nocturnal feeders. Typically, it is those shiny/slimy trails they left behind that help you determine the problem is slugs.

You might have noticed I didn’t call them an insect since slugs are gastropods which identifies them as related to clams and mussels. Slugs can vary quite a bit in size from between half an inch to more than 4 inches in length. Slugs tend to lay between 20 and 100 eggs at a time in moist cracks in the soil or in your garden containers. The eggs hatch in about 10 days but maturing to adult status can take 3 months to a year.

The young ones work their way through the soil eating seeds and roots. As they mature, they expand their diet to include leafy plants like hostas. Damage from slugs looks like an irregular shaped hole in the leaf with smooth edges.

Since slugs prefer a moist environment, your first line of defense would be to make sure your plants are not crowded and have plenty of air circulation. In addition, if you are watering in the evening, you should shift to watering in the morning. Watering in the morning is best for your plants but especially for hostas. Wet leaves and mulch at night provides a perfect environment for slugs.

As far as control goes, you have several options. Interestingly, slugs appear to be attracted to liquids that have been fermented. Because of this, you can place several shallow containers like a cat food can or a disposable pie tin filled with beer around your hostas. The slugs will get into the beer, become trapped, and drown.

You can also use scrap boards to trap slugs if you don’t want to waste beer. Place the boards near your affected plants in the evening. When they are done feeding at night, they will retreat to underneath the boards. In the morning you can lift up the boards, then remove and destroy the slugs.

If this hands-on approach is not your style, there are a couple of chemicals you can use for control called molluscicides. The standard insecticides you may have in your arsenal will not be effective. You may run across a molluscicide called metaldehyde which is pretty common. However, products containing metaldehyde are not approved for use around edible crops and are toxic to dogs, so this one would not be on our recommended list.

There are better choices that contain iron phosphate which are effective and won’t put your dogs at risk. These products have names such as Sluggo or Escar-Go! As always, follow the direction on these products for application. 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: Mark Dreiling, Bugwood.org