If you are noticing numbers of tiny moths near your kitchen, pantry, or food storage areas, they could be Plodia interpunctella, also known as pantry moths. The presence of these little moths means you might be facing a pantry infestation, one that could decimate your stored foods and grains if not addressed.
Read on to learn how to prevent and get rid of these pesky pests.
What Do Pantry Moths Look Like?
P. interpunctella is one of several insects known to feed on stored grains and other dry foods. It is known by several common names, including pantry moth, Indianmeal moth, flour moth, grain moth, and weevil moth. Adult moths are quite small (1/4 to 3/8 inch in length) with a wingspan of 1/2 to 3/4 inch. Their small size makes them easy to overlook—until your kitchen storage is overwhelmed by them.
Pantry moths are found almost everywhere in the U.S. and will feed on almost any dried goods. They especially love raw and processed grain products, such as cereals, pastas, and dog/cat food. An infestation is not a sign of poor housekeeping—in most cases, the infestation is brought inside from products purchased at the store (especially grain products purchased in bulk).
Adult female pantry moths will lay hundreds of eggs, which hatch into small white caterpillars (larvae) less than 1/2 inch long. These larvae will spend the next several weeks eating their way through your stored goods, spinning small, sticky webs as they go. You may see these webs inside your goods or stuck to the sides of the bag.
Eventually, the larvae will pupate (go dormant) before hatching into more moths. This entire process can take from 1 to 10 months depending on environmental conditions, so by the time you find visible moths, there is a good chance you have an infestation present in any dry food containers that are not sealed airtight.
3 Ways to Get Rid of Pantry Moths
Pesticides are not the best course of action for pantry moths in a home kitchen, especially because you want to avoid chemically treating in food prep and storage spaces. Getting rid of an infestation of pantry moths is not hard, but it does involve detailed investigation as well as consistency and patience. Mostly, it's a matter of closely inspecting each and every dry food item in your storage area, discarding affected items, and cleaning the area thoroughly before restocking.
Remove, Inspect, Discard
Inspect all food in your pantry for signs of infestation. Inspect all dried goods and grains at the store before you purchase them and again before you bring them inside, especially if you are purchasing large quantities or buying from the bulk bins at your local market.
Look for adults as well as larvae (small worms) in and on food packaging as well as webs. These may belong to moths, not spiders. Also, don't overlook other insect activity you find. The term 'pantry pests' includes a variety of pests including beetles (like carpet beetles), weevils, and flour mites.
Grain-based products like flour, cereal, pasta, and baking mixes are pantry moth favorites, along with nuts and sweets, but don't limit your search to these items. You may find larvae tucked into the edges of cans, on spice jars, or even in unopened packages and sealed canisters. In this case, inspect closed bags for small holes where pests have chewed their way out.
If you have pets, be sure to check their food, too. Toss any infested foods that you find. Infested items should go straight to your outdoor trash can. Placing them in your kitchen trash will only allow the problem to spread.
Clean Everything With a Vacuum
Give your pantry or cupboard a thorough cleaning. Pull out your shelf liners and clean or replace them. Vacuum the shelves, paying special attention to the corners, undersides, shelf brackets, and mounting hardware. Vacuum the walls, baseboards, trim, floor, ceiling, and door (including the inside edge, hinges, and knob). Don't forget to thoroughly vacuum the floor, too.
When you're done with your clean-up, remove the vacuum bag, and take it out to your outside trash bin. Make sure to wash out the dust compartment if you used a bagless vacuum. You don't want to harbor moth larvae in your vacuum bag or filters!
Change Storage Methods
If you have space, you can store many grain or nut products permanently in the freezer or refrigerator rather than in the pantry or cupboards. This will protect them from pantry pests and keep them fresher longer.
Inspect your groceries before purchasing, and then again before you bring them inside. Also consider storing new groceries in a different spot (i.e., a good distance from the pantry). This can be a permanent strategy, or you may want to do it until you've had a chance to monitor the affected pantry and make sure the problem is fully eliminated.
In addition, consider transferring your grains and other dry food products in mason jars, tins, or other tight-sealing containers. This way, If you inadvertently bring food home from the grocery store that contains moth eggs or larvae, the moths won't be able to get out of the jar when they hatch and you'll only have that one jar of food to throw away.
Lastly, make sure to FIFO your grains. If you've worked in food service, you know exactly what this means, but if you haven't, FIFO stands for "first in, first out." FIFO is how commercial food processors, grocery stores, and restaurants make sure their food doesn't sit in storage too long where it could spoil or fall prey to pantry pests. Only purchase what you will use in 2-3 months time, and use the oldest products first. Always check your expiration dates and organize your pantry accordingly. The bag of flour with the earliest expiration date should be the one used first.
What Causes Pantry Moths?
Pantry moths almost always gain entry to your home through purchased dry food items that were contaminated at the food processing plant, packaging plant or grocery store. Once in your home, pantry moths can spread if the products are stored in cardboard or thin plastic containers that allow the larvae to eat through and spread to other containers.
These insects and their larvae feed exclusively on dry food materials, especially grains, and it requires warmer temperatures to breed and thrive. Their need for warmer temperatures means cold storage can be a great option. In fact, in regions where pantry moths are prevalent, cold storage is a common strategy.
How to Prevent Pantry Moths
To avoid future infestations, inspect all dried goods and stored items before bringing them inside. Then, consider storing your flour, baking mixes, oatmeal, and nuts in the freezer, or freeze these items for a week before moving them to your pantry. It will kill any larvae that might be present in the foods that you bring home from the store so you don't introduce them to the rest of your pantry.
Use a vacuum to clean up food messes in your pantry as soon as they happen, and give your pantry a thorough gut-and-clean several times a year. This will help you avoid infestations and alert you to any potential problems before things get out of hand.
If you maintain a grocery stockpile, be sure to inspect it regularly for moth activity and follow the same food storage practices that you follow in your kitchen. You probably don't visit your stockpile nearly as often as you visit your pantry, so it would be easy for a problem to go unnoticed.
Pantry Moths vs. Clothes Moths
Pantry moths are a different species from the common moths that cause damage to fabrics in closets and dressers. The two most common fabric-eating moths are Tinea pellionella and Tineola bisselliella. They are similar in size and shape to pantry moths, but their coloring is different and they are not known to infest food-storage areas. Pantry moths usually have more distinct reddish-brown hues on the outside wings, while clothes moths are more uniformly gray.
However, in a home with a severe infestation of pantry moths, the insects sometimes use nearby fabrics as a site for laying eggs. It's possible you may find signs of pantry moth webbing and even tiny caterpillar larvae in clothing storage areas located near pantries and other food storage areas. Pantry moths and their larvae, however, do not consume textile fabrics. If you are also noticing holes in the clothing, then the infestation is likely clothes moths, not pantry moths.
Do pantry moths spread disease?
Although the presence of pantry moths (and especially their squirming larvae) may disgust you when you find them in your stored foods, there is no indiction that these insects spread diseases in the same way that common houseflies do. They can, however, sour your baking goods with contamination if the infestation is severe.
Do pantry moths bite?
Very few moths are known to bite people, and pantry moths are no exception. These insects simply feed on dry foods and are never known to bite.
Where do pantry moths come from?
In virtually every instance, pantry moths come into your home from purchased dry foods that were contaminated at food processing or packaging centers. Once in your home, however, they may spread to other areas of the house.
Will pantry moths go away on their own?
Pantry moths are not a seasonal visitor like cluster flies, box elder bugs, or some other insect pests. They will remain in your house—and spread—as long as there is dry food to eat or until you make efforts to eradicate them.