Miller Moths Be Gone

Periodically, residents on SFTR are visited by pesky miller moths. In some years, the infestation is not severe, while in others, it is extremely annoying. That has been the case in 2023. At night, if we opened our garage doors, moths would swarm around the lights in the garage and house. We had to start parking our cars in the garage but not entering the house from the garage to avoid a swarm of these critters from entering our home. During the day, if we opened the garage doors, moths would fly out in large numbers, sometimes causing the garage door sensors to reopen the garage doors. And of course, there is the nasty fluid they leave behind when they are hanging out on your ceilings, walls, and furnishings.

This article provides some tips for managing this annual visitation.

First, here are some quick facts about miller moths (courtesy of Colorado State University Extension):

  • The ‘miller moth,’ common in Colorado and adjacent states, is the adult stage of the army cutworm.
  • During warm months the ‘miller moths’ migrate to higher elevations as they seek flowering plants. Areas close to the mountains receive moths that may have migrated well over a hundred miles en route to summer feeding sites.
  • During outbreak years, miller moth flights typically last five to six weeks, generally starting between mid-May and early June. However, they tend to cause most nuisance problems for only two to three weeks.
  • Miller moths avoid daylight and seek shelter before day break. Ideally, a daytime shelter is dark and tight. Small cracks in the doorways of homes, garages, and cars make perfect hiding spots. Often moths may be found clustered together in particularly favorable sites. Since cracks often continue into the living space of a home (or a garage, car, etc.) a ‘wrong’ turn may lead them indoors. At night, the moths emerge from the daytime shelters to resume their migratory flights and feed.
  • They do not feed on any household furnishings or food. Moths in the home will eventually find a way outdoors or die without reproducing.
  • When large numbers die in a home there may be a small odor problem (due to the fat in their bodies turning rancid).
  • Miller moths may spot drapes or other surfaces, such as unfinished wood because they excrete fluid for most of their adult life.

How to Rid Your Home of Miller Moths:

After doing some research online, I encountered several suggestions for dealing with these little invaders. One suggestion described hanging a light over a bucket of soapy water. That seemed too dangerous to me. The best solution I found was to use peppermint. Apparently miller moths do not like that smell.

Here is what I tried and they all worked to get the miller moths to leave:

  • Initially, I didn't have any peppermint oil but I had peppermint candy sticks. I ground some up in a blender, poured it into a ziploc container, and mixed in a little olive oil.
  • Later, I obtained some peppermint oil which was poured onto cotton balls and placed in a jar lid or ziploc container.
  • The easiest solution was to purchase peppermint air freshener which I found online at Amazon (Citrus Magic Holiday Odor Absorbing Solid Air Freshener, Peppermint).

    After placing these items in our garage, RV, and shed, most of the moths were gone the next day and did not return.

Cleaning Up from Miller Moths:

  • If they enter your home, the best thing to do is use a hand-held vacuum to collect them while alive (NOTE: do not leave them in the vacuum a long time or they will begin to smell).
  • Vacuum or sweep up dead moths to avoid the smell as they decompose.
  • Wash off the liquid they leave on surfaces or fabrics.