Indian Meal Moth
Indian Meal Moths are probably the most encountered pantry pest that are found in homes, grocery stores, warehouses, etc. in the United States. They may one of the most important pests as well and although they are commonly encountered in the United States, Indian Meal Moths can be found worldwide. The common name – Indian Meal Moth – was given to the species of moth by an American entomologist when she found the moth feeding on cornmeal, also known as “Indian corn”.
Life Cycle & Identification
Indian Meal Moths go through a complete metamorphosis: egg, larvae, pupae, and adult. The entire life cycle of the Indian Meal Moths take anywhere between 30 days to almost a year at 300 days. In a favorable condition, however, this species of moths can go through as many as 8 generations in an entire year.
The eggs of Indian Meal Moths are different from some other species of moths in that they are not sticky. Female moths will lay between 60 to 400 eggs on top of a food surface, typically in groups of 12-30 eggs and they will hatch anywhere between 2-14 days. They are a whitish color and oval in shape. The minute size of the eggs are difficult to see without the aid of a microscope.
Newly hatched larvae are very hard to see due to their small size and actually, it is during the larval stage that there is the most noted damage done to grain products and other pantry products that may become infested. As they get larger, they start to have tints of color. They will usually be a faded yellow color and some even have shades of tan, pinks or even have greenish tints, and a lot will remain the white color. They have a brownish “head” capsule and legs near the head (three sets) and legs on the abdomen (five sets). Larvae at full maturity before the pupae stage are nearly 12mm long. They are spotless which also distinguishes them from similar pantry pest moths species. Larvae will feed alone, in seclusion, as they start to spin silk webbing around themselves and also around the food materials. The webbing can be seen in food packages along with fecal pellets. Larvae are actually very active and will molt several times before entering the pupa stage. They will then wander off and seek a protected location to begin pupating. Their cocoons can actually be found in totally separate rooms from the rooms that have infested material.
The cocoons are a light brown color and can be found on the surfaces of grain and on the walls of the grain tins. Adults won’t emerge from the cocoon for another 4-30 days.
When at rest, adult Indian Meal Moths are about 8-10 mm long with a wingspan of 16-20 mm long. They are very distinctive with bronze coloring on their outer forewing and a basal half that is a yellowish, creamy white color. They will mate and then females will lay a new generation of Indian Meal Moth eggs. Adults can live anywhere between 4-25 days.
Habitats & Damage
Indian Meal moths are pantry pests that usually enter the home by hiding in packaged goods and groceries that are brought home. In the summertime, they may fly into the structure through any open window or door. They can be found in a wide range of food products. These range from dried fruits to cereal to nuts and grains, candy, pet foods, spices, and any other processed food that has vegetable origin. They will also be found in dried flower arrangements and potpourri. They can even be found in powdered milk and flour. The larval stage of the Indian Meal Moth will be the main cause for damage to the products. Mold can become a problem in grains. And although this is a problem, the biggest problem is when larvae that feed leave their feces and also when they leave the silk webs that they spin in the grain.