Ask a Master Gardener

MIgrating Moths

6/3/23

We have a ton of moths this year. I don’t remember a year like this. What’s going on? JD

We have been getting quite a few calls from not only homeowners but TV stations asking about these moths and it’s a pretty interesting story.

If you are seeing an abundance of moths around your landscape, they are likely one of these two; the Forage Looper Moth (Caenurgina erechtea) or the Miller Moth (Euxoa auxiliaris). Currently, these moths are migrating from East to West on their way toward the Rocky Mountains likely in search of cooler temperatures at higher altitudes.

While it’s not always a mass migration like the one we are currently experiencing, this year’s migration likely means that there are a sufficient number of flowering plants to provide nectar for the journey which can be seen as good news for pollinators.

These mass migrations usually start around the middle of May and continue through June with the greatest concentration lasting a couple of weeks. This year’s migration is so large that it can be seen on weather radar in Colorado.

For the most part, these moths tend to avoid traveling in the daylight hours and will try to find some safe place to pause their journey in a home or structure before the sun rises. They may try to enter your home through a door, a broken screen, or under garage doors that are not sealed. Greenhouses that contain plants would be especially attractive. Flowering plants attract them. As pollinators, if you can put up with this temporary inconvenience, they can be beneficial to your landscape.

Your best strategy in dealing with these migrating moths is to make sure any potential entry point into your garage, screened in porch, or home is sealed properly. If you are dealing with moths that are already inside, the recommended strategy is to vacuum them up using something like a shop vac.

Pesticides are not recommended for a variety of reasons. First of all, if they are indoors and you use a pesticide, you’ll still want to vacuum up the dead moths. And outdoors, pesticides can have a negative impact on the pollinators we want to attract to our gardens.

One thing you can do outside if these moths are creating a problem is to place a bucket, partially filled with soapy water outdoors and suspend a light above the bucket. The light will attract the moths and as they get into the soapy water they will die. But, be sure to place these “traps” away from any potential structural entry point so that you are not attracting them to your home.

Wind chimes or some other type of noise also seems to disorient the moths into avoiding that area. However, those are only good if the wind is blowing.

The bottom line is you don’t really need to do anything if they are not getting into your home and causing trouble. Just know we are witnessing one of nature’s mysteries and it will be over in a few weeks. 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: Robert J. Bauernfeind, Kansas State University, Bugwood.org