Moths are 3/8 to 1/2-inch long with wings folded over the back. Wings are two-toned, with the bases a pale gray and the ends reddish brown or copper. Larva are dirty white with brown heads. They grow to about 1/2-inch long and may become yellowish, pinkish, brownish or greenish.Indian meal moths are often mistaken for clothes moths when they are detected flying around in the home. The clothes moth does not have two-toned wings. Their wings are uniformly gray. Another stored grain infesting larva species, the Angoumois grain moth, infests seeds of corn, wheat, oats, sorghum, barley and other crops. Adult moths are small, all yellow moths with a 3/5 inch wingspan. Egg-laying females infested seeds either while crops are in the field or in storage. Larvae tunnel into seeds, feeding on the germ and endosperm, and form silk tubes in which they pupate. Their life cycle is completed in about 5 weeks and up to six generations can occur annually. Other major stored grain pests are rice weevils, and granary weevils.
Life Cycle: Night-active female moths lay eggs, singly or in clusters, on suitable larval food. Larvas hatch from eggs and produce silken tunnels for protection while feeding. Larval development varies in length with temperature and type of food material. Just before pupating, larvae leave the food source. Larvas can be found crawling on walls and ceilings searching for a place to spin a cocoon. Development from egg to adult takes from 27 to 305 days, and 7 or 8 generations can occur in a year.
Habitat and Food Source(s): Larva have chewing mouthparts. Adults have siphoning mouths. Larva feed in flour (including whole wheat and cornmeal or Indian meal)., shelled corn and other broken stored grains, dried fruit, seeds, crackers, biscuits, nuts, powdered milk, chocolate, candy, red peppers, and dog food. A common food source is bird seed. Because it is not treated for human consumption the moth larva is often imported into homes with the feed. Larva produce a loose silken mat on top surface of infested food material.
Pest Status: Moths are often found flying in kitchens and other rooms of the house, being a nuisance to occupants; appearance of moths is an indication of a breeding population of larva in some type of stored food.
If the problem is severe and widespread, contact a reputable, licensed pest control operator who has the training, experience, equipment, to get the control job accomplished. An experienced professional may not need to use pesticides.
Before purchasing, examine foods such as milled cereal products, flour and dried fruit for infestations. Examine broken and damaged packages and boxes to avoid bringing stored pests accidentally into the home. Check the packaging date to ensure freshness.
Purchase seldom-used foods in small quantities to prevent long storage periods of a month or more. Susceptible material stored for six months or more, especially during the hot summer months, has the possibility of developing into serious infestations. Store susceptible foods in insect-proof containers of glass, metal or plastic ware with tight-fitting lids, ideally screw-type. Highly susceptible foods, such as spices, can be kept in the refrigerator and other foods in the freezer. Always use older packages first, and inspect frequently to avoid any spillage which might attract insects. Properly ventilate the storage area to discourage moisture-loving pests.
Foods of questionable infestations or even lightly infested can be supercooled or superheated. Place exposed or suspect foods in a freezer at 0°F. for four to seven days or in a microwave oven for five minutes or in a shallow pan or tray in the oven at 140°F for one hour or 120°F for two hours. Spread the material thinly to permit effective cold or heat penetration to kill all life stages of the pest. If in the oven, stir food periodically to prevent possible scorching. Dried fruits can be placed in cheese cloth bags and dipped into boiling water for six to ten seconds to kill external pests. However, seeds saved for planting may have the germination reduced after superheating or cooling. Sifting the food material will remove possible insect fragments and any remaining will not cause harm if consumed. After insects are killed, contaminated food might be used outdoors during winter months for bird feed.
Careful sanitation is the best method to avoid stored product pests. After removing all food, food packages, utensils, dishes, etc. from the cupboard, shelves or storage area, use a strong suction vacuum cleaner with proper attachments to clean up all spilled foods (toaster crumbs, cornmeal, bits of pet food, raisins, etc.) from cracks and crevices, behind and under appliances and furniture. Pull out heavy appliances from the wall and scrub with soap and hot water. The ability of these insects to find a small amount of food and survive is amazing. After shelves are thoroughly dry, cover with clean, fresh paper or foil before replacing with food or cooking utensils. Remove and destroy any cocoons found in cupboards and other sites.
Locate the source of infestation and quickly get rid of it. Dispose of heavily infested foods in wrapped, strong, plastic bags or in sealed containers for garbage disposal service or bury deep in the soil if permitted and practical. If detection is made early, it may be the only material infested and the problem is solved. Be sure to carefully examine seldom-used foods, especially in least disturbed storage areas. One can spread suspected foods on a tray to determine whether infestation is widespread. Inspect unopened cardboard boxes since pests can chew into these boxes and plastic inserts.
Pheromone traps are commercially available for inspection, monitoring, and pinpointing infestations of adult Indianmeal moths. Insects use pheromones to communicate with each other, and are natural compounds created in the insect body. Many have been isolated in the laboratory and now used to lure insects into sticky traps.Adult moths live only five to seven days with their major function to reproduce. Male moths are attracted to pheromone scent (sex-attractant). Traps can be hung indoors next to the ceiling, behind shelves, etc. to capture moths on a sticky board. In food warehouses, some use five traps per 1,000 square feet. A few well-placed traps can detect moths. About one in eight Indianmeal moths that approach a pheromone trap enters it. The trap alone is a “monitoring tool” not a control method.
The use of insecticides is discouraged around food materials. However, aerosol sprays of synergized pyrethrins, labeled for this use, will control nuisance moths flying around rooms. (Follow label directions and safety precautions). Killing the adult moths will likely have little or no effect on the problem because the eggs and larva will be near a food source.