Are Pantry Pests Bugging You?
by Jody Green, Extension Educator
Indian Meal Moth
Indian meal moth is relocated into the home after product purchase. The adult Indian meal moth will lay their eggs near a food source, and when the eggs hatch, the larvae crawl into the food product via holes in packaging.
Immature Indian meal moths are caterpillars that have a distinctly dark head capsule, three pairs of thoracic legs and five pairs of prolegs on the abdomen. Indian meal moth caterpillars are sometimes mistaken for maggots, which are the larval form of flies. Maggots lack a head capsule, are completely legless and do not thrive in dried goods.
The Indian meal moth larvae have chewing mouthparts, which allows them to gain access into unopened packages of food. During its larval form, it can appear to be yellowish, greenish or pinkish in color depending on its food source. It eats, grows and molts five times, growing up to 5/8-inch before it travels out of the product, leaving silken threads behind to where it will pupate.Adult moths emerge from cocoons; they are 1/2-inch long with a wingspan of 3/4-inch. They can be distinguished from other moths by their two-toned markings on their wings, which are whitish-gray closest to the head and reddish-brown with a copper luster on the end of the forewings. Adult moths are short-lived and do not feed, therefore damage to food product is done by the larval or caterpillar form.
Signs of Indian meal moth infestations in the home include:
- adult moths flying around inside the house, usually attracted to lights, fluttering around screens at night,
- silken threads and webbing on/ in food products, packaging, storage shelving, cupboards, walls and ceilings, and
- larvae crawling in the food products that contain flour, cereal, stored grains, chocolate, nuts or dried fruits.
Flour beetles are also quite common in homes. There are two flour beetles with similar biology, behaviors, life cycle and feeding habits, the red and confused flour beetles.
The red flour beetle has a three-segmented club, and the confused flour beetle does not. This difference, though slight, provides an important difference when dealing with origin of the infestation because the red flour beetle is a flier and the confused flour beetle is not capable of flight.
The larvae are creamy to yellow-brown, with light hairs and pointed projections on the last segment. Before pupation, mature larvae are about 1/4-inch long. Adult flour beetles are approximately 1/8-inch long and reddish-brown in color. All life stages can be found in large numbers feeding on broken kernels and other grain products.
Signs of red flour beetle infestations in the home include:
- adult beetles flying around inside the house, usually attracted to lights, may accumulate in and along window sills,
- larvae and adults in food products that contain flour, cereal, dried pet food, dog treats and all grain products.
Treatment strategies for Indian meal moth and red flour beetle do not include insecticide use inside the home. A thorough inspection is necessary to locate and eliminate the source of the infestation and provide a long-term solution. Most people overlook prepackaged and prepared foods, unopened packages and non-food items, but a variety of products are vulnerable.
There are pheromone traps available that attract the specific pest to a sticky glueboard or pitfall trap, but these are preferred as a monitoring tool, rather than solely a control method.
Prevention and sanitation is your best protection against pantry pests. Here are some ways you can prevent infestations in the home, minimize wasted food and save money:
- Before purchase, check for rips or tears in packaging and other signs of infestations.
- Avoid buying in bulk and storing large quantities of products in the pantry.
- Store products in air-tight, insect-proof containers.
- Use the oldest products first to ensure freshness and proper stock rotation.
- Store infrequently used products in the refrigerator or freezer.
- Clean-up spills and crumbs in food storage areas so not to attract pests.
- Vacuum cracks and crevices where insects can hide and grains can accumulate.
- Dispose infested foods in trash and put outdoors.
- Non-food items that may be infested include dried flowers, museum specimens, spices and dog biscuits (red flour beetle).
- Indian meal moth have been known to infest candy bars and baked goods in vending machines.
More Pantry Pests:
Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the University of Nebraska–Lincoln is implied. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office