What is an Indian Meal Moth?
Boasting the scientific name Plodia Interpunctella (Hubner), the Indian Meal Moth is a widely known pest affecting stored grains within the United States of America.
This household pest reproduces quickly in Colorado homes and has been occasional troublemakers in Pennsylvania. You’ll find the Indian Meal Moth snuggly tucked away in your pantry gorging on your grains, cereals, dried fruits, nuts, dried herbs, and a plethora of processed foods. While the caterpillars invade your pantry and food items, adult moths fly senselessly around your home, becoming a common nuisance.
Description of the Indian Meal Moth
Sporting a distinguishable appearance from other grain/pantry pests, the moth’s wings have a breadth of about ¾ inch (18-20mm). The Indian Meal Moth bears odd markings on its forewings, with a hue of reddish-brown.
The moth has a park of copper on its outer wing, and a greyish-white (dirty white) moving closer to its head. You can call the moth multi-colored if you will, as its wings wear the colors reddish-brown (gives off an orange cast), bronze, and greyish-white. Adult moths gravitate to light and mostly roam at nights.
Larvae, when bred, is hard on the eyes; they are difficult to see. Indian Meal Moth larvae can often be found in various shades – ranging from yellow, green, and a pinkish hue. When fully developed, they are approximately ½ to 5/8 of an inch in length. They do get around with at least 3 sets of legs close in proximity to their brownish colored head and five sets of legs on the abdomen. Don’t be surprised if you find silken web in your pantry, as larvae while transitioning to a fully-grown, will leave threads of those behind. You can pinpoint an infestation of this pest by their loosely clinging webbings.
Life Cycle of the Indian Meal Moth
Once the temperature within your grain bin is above 50F, meal moths will survive and thrive. The meal moth’s life cycle hits completion in about a month or less, depending on food quality and temperature. However, to fully develop, the meal moth takes a little longer under normal circumstances.
A female Indian Meal Moth can lay up to 300 eggs on foods or crevices close in proximity to where they’ll feed. As newly bred larvae are very small, they can easily access food in most packages. In fact, they are so small they can squeeze through a sixty-mesh screen. New larvae are more inclined to feed on the surface of grain (usually 1-2 inches), while large larvae love grain germ.
Indian Meal Moth Damage
The larval stage of the Indian Meal Moth inflicts the damage. They feed on grains to be consumed by humans and animals. When fed on, grains might increase in moisture or water absorption, later giving birth to mold. Some larvae also leave behind silken webs and droppings, which is really seen as the biggest contamination of grain.
You’ll also find live and dead insect parts in your grains.
Indian Meal Moth Control and Management
To bring an infestation of Indian Meal Moths under control, the following suggestions can be considered:
1. Scrutinize all foods that you think might have been exposed to an infestation. It’s shrewd to examine your pet’s food and wrapped products (even unopened ones). Once the package is infested, it should be thrown out, as there’s no appropriate way to separate the insects from the food products.
2. If a food package is opened but remains uninfected, the contents should be immediately transferred to a container (mainly glass jars) with strongly fitting tops.
3. Once an area has been labeled as infested, remove all food containers and utensils. You also need to clean shelf papers.
Pay close attention to crevices and cracks. These areas might contain scraps of food such as flour and other products. If a cocoon is found, destroy and remove it.
4. Cleaning completely will control these insects and a pheromone trap can be used to lure in flying moths. Note: You don’t need to use pesticides in certain areas when dealing with food storage.
5. Observe the area after clean-up. Should they reoccur, clean the area again.
Homeowners should make it a practice to buy meal products and flour in sufficient quantities to serve the family, not in excess. That is because long-term storage of the foregoing will result in an infestation.
Other Treatments and Control Factors
Generally, it’s not recommended to treat food storage areas with chemicals. However, especially in difficult or extreme situations, insecticides can be used to treat storage corners (the corner of storage areas). A spray can or paintbrush can be used to treat these areas. After application, ensure food is not restored until the applied material is dried.
Indian meal moth build-up can be prevented by using a grain dryer fan. Once air flow is increased, this will moderate grain temperature and lessen moisture levels, thereby creating an unfavorable environment for Indian meal moths.
If you’re looking to store grains over a long period (maybe six months) try to apply residual insecticide to the floor and structure walls. Once the bin is replete with grain, a residual insecticide should be applied to the surface. For more information, visit the Penn State Agronomy Guide for recommendations.
Indian Meal Moth Traps
If you’re struggling with Indian meal moths, here’s a list we recommend.