Indian Meal Moths

Indian_Meal_Moth

Indian Meal Moth Plodia interpunctella

Overview

This moth is found more often that any other pest on stored food products in the home pantry in New England. Its name comes from the United States, where it was first recorded as a pest of Indian corn or maize and like maize itself, may have a South American origin. At any rate, it is now cosmopolitan in distribution. This small moth is responsible for most of the insect problems in natural food, flour, grains, dried fruits, pet foods, powdered milk, corn meal and especially nuts during the holiday season. This is a serious pest, it can also attack chocolate.

Identification

The caterpillar, the feeding stage of the life cycle, is dirty white to pink in color and reaches a size of one inch before it turns into a moth. IMM_larva Larva or caterpillar feeding stage.

This caterpillar, which looks like a small worm, leaves a silken thread behind wherever it crawls and spins a web as it becomes full grown. Under normal room temperatures, and depending on how nutritious your stored food is, the caterpillar stage lasts from 2 to 5 weeks. Under colder temperatures they make take as long as 2 years to develop. When full grown as a caterpillar, they crawl to the surface of the food material and often continue crawling up to the tops of shelves and across to ceiling corners. They construct a silken cocoon and emerge as adult moths from one week to a month later.

Adult moths have a broad transverse band of light color just below the head. The rest of the month which is about .25 inches in length, is a dull redish-brown color. Adults can fly during the day as they search for a mate and a new pantry food source.

Biology

Since a female moth lays from 100 to 300 eggs during her lifetime on food in the pantry, it can potentially be difficult to rid your home of this pest. The eggs are laid singly or in groups on food material and they are difficult to see. You may first become aware of small particles of food attached to silken webbing or you may be oblivious to what is in your stored food until you see moths flying around your home in the evening, often attracted to lamps or your TV set.

In the past, kitchens often had pantries and food in the pantry was stored in heavy crockery with tight lids. The modern approach is to keep all food in sealed plastic containers. Food is often brought into the home already contaminated from the grocery store or warehouse. Under unusual conditions these moths can attact “green” building materials that look like particle board but are from crushed corn husks.

Control

Getting rid of these moths is basic once you become determined to store your pantry food in insect tight containers.

1) First you may want to search out and dispose of infested food items. Go to the bottom of the assorted nut bowl and you may find that the walnuts are infested with these moths. If in doubt about flour or meal, you can continue to check on it after storing inside insect-tight containers and only dispose of it if you are sure it is infested.

2) Using one of the many brands of plastic containers now available in assorted sizes to store food is the ideal answer to this pest problem. These insects can chew their way through typical bags of pet food and bird seed. Large bags of rice and nuts and other foods that are kept stored for longer periods in the kitchen are at a higher risk of contamination.

3) You do not need to use any pesticides to control this moth. You may wish to clean up shelves with a vacuum attachment and remove spilled food material to make sure that there is no lingering moth problem. The adult moths will die out in one to two weeks and will be unable to re-infest your pantry if you are careful in storing your food.

In the future, if you do store large quantities of food, do not leave open for long periods of time. If you purchase a food item and notice afterwards that it is infested, you can usually obtain a refund by demonstrating that your food is kept in insect-tight containers. A majority of cases of Indian Meal Moth are brought into the home in packages that were infested in the store, warehouse or delivery truck.

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