A common question that we get here concerns moth infestations, as in:
"Help!... I've got zillions of little gray (or white, or some other color) moths in my kitchen (or bedroom or broom closet) and I can't seem to get rid of them...what are they, where are they coming from, and how can I get rid of them?"
Sorry to say that if you want positive identification of your species, we cannot currently help you. Moths of North America is being built on the web, and it does not presently cover the many species that may be involved in home infestations across the nation. One resource that may offer help in identification for those of you in the northwestern states is a pamphlet on meal moths put out by the Washington State University Cooperative Extension Bulletin Program. No matter where you live, this pamphlet offers excellent advise on controlling infestations of moths that infest grain-based products.
The moths are coming from one of two places. Either they are outside and are coming in or you are growing them in the house. Check your screens at night when the infestation is growing. If you find them on the outside, a few repairs to plug the entrances should solve the problem. If you don't find any on your screens, but still suspect that they are coming from outside the house, take a look around for other insects of similar size...do you have an abnormal number of mosquitos or midges or other such in the house?
If not, you are probably running a moth farm somewhere in the house. Start looking for the source in the room where you find the largest concentrations of moths.
Most frequently, this will be the kitchen, because the most likely source of the infestation is cereal products. Check the flour and corn meal supplies; look in the bag or box of rice; also muffin and cake mixes. Don't ignore a package just because it is still unopened...even the best of modern packages may still have entranceways and exits for small insects. (No need to actually open these, but examine them for small holes or other evidence of infestation.) Don't forget the dry cereal boxes or the container of oatmeal that you put away last spring. What you are looking for is larvae or fecal material (the latter is less unappetizing if you call it "frass," like the entomologists do) in the foodstuff itself, or pupae and pupal cases on the sides of the container, on the shelves, back and sides of the cupboard, or on nearby paper products such as napkins or coffee filters. Infested foods often have a cobweb-like material in them. You may have to dig deep into your cupboards... although you may have picked up a fresh container of something that is contaminated, it is more likely that your infestation is coming from something that you forgot you had or otherwise "lost" in the back of the larder. Still can't find it? Check the dry dog food or cat food; also the birdseed. And look in unlikely spots; husbands and kids sometimes put things away in really strange places.
Once you've found the infested foodstuff or foodstuffs, bag it up and toss it out. Don't be surprised if discarding the infested food doesn't immediately end your moth problem. Not uncommonly, a number of larvae will have pupated in your cabinets, and these will emerge over the next few weeks. It generally isn't worth trying to use insecticides to control the residual pupal population. Many of the pupae are in relatively inaccessible crevasses and cracks where they are unlikely to receive a lethal dose, and avoiding contamination of your foodstuffs while spraying is a major headache. Better to just seal your foods from the moths until the infestation dies out.
However, if you don't see a difference soon, look further to see if something else is infested, and recheck things that were "moth free" during your initial search...it is possible that you are dealing with a second generation infestation.
If your infestation is centered in a bedroom, you may be dealing with cloths moths. However, it is uncommon to see really large hatches of cloth moths. If you suspect that they are involved, search your closets and chests of drawers for woolens, and inspect each item of clothing for larvae and holes. If you find evidence of cloths moths, you need to kill or physically remove the larvae before you move the clothing to safe storage in a cedar chest or mothballs (both are only repellants). One of the safest ways to kill them is by freezing, either in a deep freeze or by exposure to sub-zero outdoor weather.
If you are concerned about the odor and toxicity of mothballs or other napthalene products, you might want to try an herbal repellant. One such mix, from Mrs. Grieve's Herbal (sorry, we don't have the complete reference) consists of 8 oz. each of powdered Rosemary and mint, 4 oz. each of tansy and thyme, and 2 oz. of fresh ground cloves. Sprinkle the mixture freely over the clothing. Another, from Rodale's Illustrated Encyclopedia of Herbs (Rodale Press, Emmaus, PA) calls for sachets of wormwood (Artemisia absinthium), either alone or in combination with mint, tansy, thyme, cinnamon sticks, and cloves. Unfortunately, no one here can vouch for the efficacy of either of these mixes. Nor can we tell you how long they remain effective or whether the mixes have any adverse effects on the clothing that you are trying to protect.