Fact vs. Fiction: Indianmeal Moths

Fiction: I found worms in my cake mix.
Fact: Chances are those weren’t worms, but Indianmeal moth (Plodia interpunctata or IMM) larvae. Adults lay eggs in the cracks and crevices of packaged food or directly on to the food. When the eggs hatch, wormlike larvae search for food. It’s not unusual to find larvae and their silk casings in the bottom of cloth grocery tote bags and on walls, ceilings, draperies (particularly in the kitchen, dining room or living room) and pet dishes, in addition to cabinets and pantry shelves.

Fiction: Eating food infested with IMM is bad for you.
Fact: There’s a strong yuck factor here, but IMM aren’t medically harmful and don’t spread diseases
or pathogens.

Fiction: IMM feed only on grain.
Fact: IMM love all kinds of grain — corn, wheat, flours, whole wheat, cereals, products made from grains, etc. They also love chocolate, dried fruit, powdered milk, dried red peppers, seeds (especially sunflower seeds), candy, pet food and dried flower arrangements.
Fiction: Fogging and fumigating are the best ways to control IMM.
Fact: For homeowners, the simplest and most effective actions are sanitation — keeping food prep and storage areas free of spills — and conscientious product rotation. Putting unopened stored products in the freezer (0°F) for a few days will kill all stages of IMM. The larvae can chew through plastic bags, but storing opened products in glass, metal or thick plastic containers with lids that seal will slow them down.

Commercially, fumigation and insect growth regulator (IGR) programs are the preferred method in the U.S. to stem the infiltration of IMM into the food chain before we bring them into our homes. Alternatives to methyl bromide fumigation are making their way to the U.S. from Europe. Many are effective, nontoxic and worth looking into as the pressure to use green processes and products increases.

You can reach the McGoverns at jeffreymcgovern@mindspring.com.