Indianmeal Moths

Those moths you are seeing flitting around the house are not coming from your wallet or your clothing. They are probably Indianmeal moths. Indianmeal moths are the most commonly found food pest in homes, grocery stores and food warehouses today. They are often mistaken for clothes moths, but in fact, they feed strictly on dried foods. They were named by an early American entomologist who found them feeding on Indian cornmeal.

Indianmeal moths are small, about 16-20mm (½ - ¾ inch) with pale coloured wings that are reddish brown on the outer section. The larvae are about 9-20mm (½ inch) and are usually cream coloured but sometimes take on different colours depending on the food source. These moths can go from egg to adult in about 1 month under favourable conditions. Females lay eggs on suitable food sources or packaging. Only the larval stage feeds.

Infestations in homes usually result from infested foods that are brought into the house. If undetected, the moths can spread from a single source to numerous other products. They will infest everything from (dried) soup to nuts. Dried pet foods and bird seed are two of their favourites but they can also infest dried fruits, nuts, chocolate products, cereals, flour and baking products. The larvae can chew through packaging including silver foil. In the past, I have had to examine foil under a microscope to determine if larvae have chewed from the inside out or the outside in. Decorative centre pieces or hangings made from nuts, pine cones or dried corn can also become infested.

Signs of Indianmeal moths include moths flying around the room or house, larvae in packaging or climbing on the walls and ceiling and webbing material in the food. The larvae will crawl away from the food source when they are ready to change into the pupal stage. They often crawl up the walls and form small cocoons where the wall and ceiling meet.

The first step in control is always to throw out any infested food products and inspect everything else that may be suspect. If you have something that you are not sure of, throw it in the freezer for 2 or 3 weeks. Keep all susceptible products in tightly sealed containers. If you don’t feed wild birds over the summer, keep any left over seed in tightly sealed bins. Inspect for and remove any cocoons that you find. Pheromone traps are available for attracting and catching meal moths but they only attract the males so will not always totally eliminate an infestation. In cases of severe infestation it may be necessary to empty the infested cupboards and have them treated. Bleach will give you the cleanest bugs in town but is not an effective insecticide.

Don't despair if you find that you have eaten half of a package of infested product, think of it as protein enriched.