There is an easier way to determine which category of moth you are dealing with: If you see moths flying around while you are up and about, they are probably pantry pests. Closet moths shy away from light and fly primarily at night. Plus, pantry moths are more likely to be flying around frequently, simply because their life cycle is relatively short — around 25 days from egg to adult. Depending on the temperature, closet moths can take a month to two years to reach the flying stage.
The most common pantry moths are Indian meal moths. The adults have wings that are brown and tan, with lines separating the colors. The caterpillars, which are whitish, grow to be about ½ inch long and create silk webbing on food. They aren’t picky eaters; they can infest flour, cereals, powdered milk, dried dog food, dried fruit (think raisins) and birdseed. The caterpillars of another type, Angoumois grain moths, develop and feed within whole kernels of grain or corn, or inside seeds.
It’s not necessary to identify the type of pantry moth, though, because the solution in all cases is the same — and it’s not pesticides. You need to find all of the food that has become infested and either toss it or at least put it in containers that will keep insects from getting in or out. And wipe out the cupboards and vacuum out crevices to remove any cocoons.
You don’t need to spend a lot of money on this cleanup. Instead of buying matching containers, you could repurpose glass jars and takeout containers with tightfitting lids. And although food with little white caterpillars and tangles of webbing doesn’t look appealing, it’s safe to eat, because pantry moths don’t spread disease. Most people, though, just throw away the food. It needs to go into a garbage can outside your home or into a food-waste recycling bin, if your community offers that.
Keeping all of your stored food in pest-proof containers doesn’t guarantee that you’ll never have a pantry moth problem; food you buy at a grocery store might be infested when you bring it home. But the containers will corral a new batch of caterpillars, so they can’t lay eggs in other food.
If the moths continue to show up once your dried food is in pest-safe containers, you might be seeing adults that emerged from cocoons spun by caterpillars that left the contaminated food before your cleanup. Indian meal moth caterpillars often crawl to ceilings or walls before forming a cocoon, and it can take several weeks for the last of these cocoons to release the moths that formed within them.
But if the problem persists beyond several weeks, you might have missed a place where the caterpillars are still feeding. Ornamental corn, dried flowers and plants, chocolate and even potpourri can be a suitable habitat. So can unopened boxes of cake mix or other packaged food. Check boxes for signs of webbing or tiny holes that caterpillars might have chewed; if you’re unsure and you don’t want to toss the boxes, put them in a freezer. At least four days at zero degrees Fahrenheit will kill both eggs and caterpillars.
Pantry pests are a nuisance, but combating closet moths can be even more painful. These pests, which are also known as carpet moths and fabric moths, may have spread throughout your house and caused costly damage before you even knew they were there. The caterpillars eat animal fibers, meaning wool, mohair, cashmere, leather, fur and feathers. That includes clothes, carpets, stuffed animal heads, family heirlooms and occasionally even abandoned birds’ nests in attics. Items stored for long periods, and carpet that is rarely vacuumed because it’s under heavy furniture, are most likely to wind up with holes or bare patches.
There are two types of closet moths: case-bearing clothes moths and webbing clothes moths. A case-bearing caterpillar makes an open-ended fiber tube about ½ inch long to shelter in as it feeds. Tubes can often be seen on top of carpet or clothes. A webbing caterpillar creates a patch of webbing over the surface and hides under it while it dines.
Pesticides generally are not very useful in dealing with a closet moth problem, because there’s no way to spray just the caterpillars; you’d also get the pesticide on your clothes, carpet and other valuable items. Instead, you should remove and either discard or treat every item that is infested or is susceptible to infestation.
The old-fashioned treatment was to hang items outside and beat them with a stick to make the eggs and caterpillars fall off. Today, dry-cleaning, laundering in hot water (at least 120 degrees), heating in a dryer, freezing it for about three days or careful vacuuming all can kill or remove both eggs and caterpillars. Be sure to launder or dry-clean clothing that you’ve worn, because clothes moths are drawn to fibers with body oils or food spills.
Before you put things back into closets, thoroughly vacuum the space, especially along carpet edges, baseboards and crevices. Consider storing items you use infrequently in plastic bins with tightfitting lids or in compression bags.
Because it’s so difficult to spot a closet moth infestation before considerable damage has been done, you might want to invest in pheromone traps, which can serve as an early warning system. The traps use the scent of a female to attract males. Only males are likely to wind up on the trap’s sticky pad, but fewer males means fewer mating partners for females. Some traps work with a specific type of moth. For example, the Raid clothing moth trap ($48.92 for 12 at Home Depot) is listed for attracting webbing moths.
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