It’s National Moth Week! Moths are definitely the underrated stepchild of the Lepidoptera order. The butterflies and skippers get all the love. This is a shame because moths can be very colorful, intriguingly interesting, and some are quite fascinating pests.
Let’s talk about one species of moth: the clothes moth. This little moth is not one of our most common pests, I am sure you will see Indian meal moths more often than clothes moths. When they do occur, they are hard to trace back to a source and even harder to manage. There are two species of clothes moths that can be pests: the common clothes moth and the casebearing clothes moth. Out of these two, the common one is commonly encountered. Hence the name.
have you ever paused to consider how insanely cool clothes moths are? Let’s look closer. These moth larvae eat hair. They eat skin. Hair, skin, horns, and hooves are all made of keratin, a protein that is infamously difficult to digest. What kind of organism can digest and metabolize keratin like this, let alone what kind of lepidopteran?
Despite the name, it is more than just “clothes” they feed on. The clothes moth can feed on nearly any natural fiber like wool, silk, feathers, furs, wool blends, hair, insect specimens, and sometimes semolina and flour. Admittedly, those last two are rare.
Because of that, they are found in more places than just the closet. Museums can have a problem with these on all types of artifacts. They have been a problem in rugs, particularly older rugs or rugs still made with natural fibers. Fur coats and garments are less common than they once were but are just as prone to clothes moth infestations. There are interesting places you might find them too: I once dealt with these in a large outing goods store that had a huge exhibit of taxidermied animals. Many universities will have collections that are susceptible like insect and bird collections. Another interesting site I dealt with was an old meeting space where people would go for seminars and dinners and such. The carpets were obviously infested, but also the old curtains and some of the chairs and sofas.
Many of these locations and goods are pretty sensitive, it’s not like we can go into a museum and spray down some ancient artifacts with pesticides. In addition, larvae (the feeding and damaging stage) are hard to see while the adults are somewhat easier and not necessarily near the damaged goods. The first step is to find the infested items. Not as easy as it sounds. Monitoring can help with this and there are some professional monitors and a few consumer ones (stick to the professional grade ones). That can narrow down where the infestation(s) are. Those items should be removed and any other items in the vicinity that have any “edible” aspects to them should also be removed, isolated, and watched.
Then things get really complicated. In many cases, your typical pest control company can not treat the infested items. Imagine spraying down a large taxidermied zebra. Not a great idea. That doesn’t mean there aren’t a few options for customers to stop the damage and ideally, eliminate the insects. If you are a pest control company, here are a few to recommend. If you are the unlucky person dealing with the pests, here you go:
Anoxic measure – eliminate the oxygen, suffocate the moths. Little risk of damaging the item, but takes a LONG time.
Physical removal – pick off the larvae and eggs. Again, little risk of damage, but high risk of missing something and takes a long time.
Freezing or heating – bring the environment to a killing temp and they burn or freeze to death. Depending on the item, high risk for damage, but much shorter treatment times.
Vacuuming – suck them up and suck up some of the fibers they could be feeding on. Low tech approach and mostly low risk, high risk of missing some of the individuals.
Fumigants – gas the space and kill the moths. Everything from mothballs to DDT and dry cleaning chemicals have been used. Aside from the fact these are deadly (to more than just the moths), Efficacy ranges and certain materials may be damaged.
Whatever method is chosen, once it is removed and isolated, the space can be treated with a number of products. It is always advisable to vacuum first and physically removed anything left in the space, particularly eggs and small fibers. A damp cloth and any light cleaning products are also advised. It takes about a month for clothes moths to develop so after two months, if no new evidence of larvae or adults or damage is present, that space is good to put items back in.
If you work (or live) in a space with susceptible items to clothes moth infestations, it is an excellent idea to be monitored at all times. This way, they can be caught quickly, before much damage occurs and they haven’t spread through an entire area.
As I mentioned, this isn’t a pest you will run into daily. When you do, it’s going to be a challenge. It doesn’t have to be, especially when you have a fractional entomologist on call to help you with whatever challenges pest control is throwing your way. Contact us!
And check out this cool video of clothes moths feeding: