Tips to help prevent moths from eating your wool sweaters

Q. Is there any way to get rid of clothes moths? I hate the smell of mothballs and would love to find an alternative way of protecting my wool sweaters.

There are two types of clothes moths – those that produce webbing and those that produce cases.  Tineola bisselliella, the web-making moth, is the more common species. Tineola pelliomella produces cases (cocoons) and is somewhat less common.

Usually, a moth infestation is discovered when you find holes in your favorite sweater. Occasionally you will see flying insects near the site of the infestation. Clothes moths are similar in appearance to pantry pest moths with two obvious differences. Pantry pest moths are somewhat larger at ½ inch vs. clothes moths at ¼ inch. Pantry pests tend to fly in a straight line and can be found in areas outside the immediate infestation. Clothes moths will flutter about and tend to stay close to their food source. 

Clothes moth larvae can damage anything containing wool, including carpet, upholstery, wool-blend fabrics, and even the wool pads inside pianos. They can also damage furs. Damage will first appear on hidden areas such as inside folds, under collars, and inside cuffs. Clothing that is soiled is more likely to attract moths, so, if possible, dry clean wool clothes before placing them in storage.

Deep cleaning closets and wardrobes will remove pests from their hiding spaces. Thorough vacuuming, giving special attention to baseboards, carpet edges, corners, areas under furniture, and shelving, will help substantially.

Mothballs and flakes are helpful, but they lose their effectiveness after a while and they leave an unpleasant smell. In a contained space, the active ingredient (paradichlorobenzene) can cause plastic to soften and adhere to fabric. Obviously, not a good thing if your clothes have plastic buttons!

Cedar, a more pleasant-smelling alternative, is only effective against the smallest larvae and will lose its effectiveness over time as well.

I recommend placing pheromone traps after you’ve cleaned and vacuumed. These trap both species and are useful in monitoring for the presence of moths, hopefully before they can cause damage. 

If dry cleaning is not an option, fumigation with dry ice will kill insects. Handle dry ice with caution: Use heavy leather gloves and do not allow it to touch bare skin. Place clothes in a box or cooler with the dry ice and close the lid, leaving it ajar because as the dry ice sublimates (turns into carbon dioxide gas directly from its solid state) it can cause a build-up of pressure in a tightly sealed container. Do this only in a very well-ventilated room or outdoors.

Pyrethrin-based insecticides are also effective against clothes moths and may be a better alternative for fumigating a closet or treating carpeting.

Los Angeles County

mglosangeleshelpline@ucdavis.edu; 626-586-1988; http://celosangeles.ucanr.edu/UC_Master_Gardener_Program/

Orange County

ucceocmghotline@ucanr.edu; http://mgorange.ucanr.edu/

Riverside County

anrmgriverside@ucanr.edu; https://ucanr.edu/sites/RiversideMG/

San Bernardino County

mgsanbern@ucanr.edu; 909-387-2182; http://mgsb.ucanr.edu