Over the Garden Gate: Keep pantry safe from pests - The Times

Over the Garden Gate: Keep pantry safe from pests - The Times

Unfortunately, some insects like to eat what we eat and if unnoticed will take up residence in dry foodstuffs in our pantries.

By Laura MurphyFor The Times

Unfortunately, some insects like to eat what we eat and if unnoticed will take up residence in dry foodstuffs in our pantries. Many dried products are susceptible: flour, cake mix, dry pasta, crackers, cereal, grains, spices, herbs, beans, rice, chocolate, birdseed, dry dog and cat food, dried fruits and more.

You may notice a winged insect, beetle, larvae or weevil on your shelf, counter or container in the kitchen, garage or storage area. Some pests gravitate to a favorite dried food, others are more general feeders.

Beetles and moths go through four life stages: egg, larvae, pupa and adult, with larvae being the most destructive, but adults the most noticed. Some common pantry pests are: Indian meal moth, cigarette beetle, drugstore beetle, confused flour beetle, red flour beetle, saw-toothed grain beetle, merchant grain beetle, rice weevil, maize weevil and granary weevil. Fortunately, these insects do not bite or sting and eat very little of what they infest.

Indian meal moth (Plodia interpunctella) is one of the most common pantry pests in Pennsylvania. The adult is nearly a half-inch long with distinctive wing markings; the base of the forewing is pale grey and the outer two-thirds is reddish brown to copper. Only larvae feed on dry foods. Silk webbing present on the surface of the product is a clue to infestation.

Cigarette beetle (Lasioderma serricorne) and drugstore beetle (Stegabium paniceum) are stout, one-eighth-inch long and closely resemble each other. Both are brown and have their heads tucked under the prothorax, but wings of the drugstore beetle have longitudinal grooves. Both can fly and have general appetites including tobacco and pharmaceuticals.

Confused flour beetle (Tribolium confusum) and red flour beetle (Tribolium castaneum) are tiny at about three-sixteenth inch, reddish brown and are scavengers, eating grain that has been damaged. The red flour beetle flies, the confused flour beetle does not, so seeing one crawling indicates a contaminated source nearby. They look so much alike their identity is often “confused.”

Saw-toothed grain beetle (Oryzaephilus surinamensis) is very active. Adults can be one-quarter inch long with a narrow, brown body and six saw-tooth like projections on each side of its mid-portion. It is especially fond of oatmeal and birdseed. Merchant grain beetle (Oryzaephilus mercatore) is similar without the projections.

Rice weevil (Sitophilus oryzae) and the maize weevil (Sitophilus zeamais) are also similar with dark, reddish-brown bodies, one-eighth to three-sixteenth inch long. A long snout projects from the head and wing covers have distinct ridges. Both can fly. They prefer whole grains and are more of a problem in grain bins and warehouses, but also like flour or cereal. Granary weevil (Sitophilus granaries) is more cylindrical at about two-tenths inch and cannot fly so it is more of a problem where grain is stored.

Infestation may occur at production, transportation, retail or in the home, especially when dried foods are stored for long periods. The following methods will help keep these pests out of your foodstuffs:

1) Purchase small quantities of cereals, grains and other dried food. Do not purchase past freshness date.

2) Examine unopened boxed products or bulk purchases at retail or when brought into the home for signs of infestation including torn packaging that can allow pests to enter or move to other foods.

3) Store products, especially products that take longer to use, in airtight glass or hard, plastic containers with tight-fitting or pressure-sealed rubber gasket lids. Some insects can eat their way through cardboard, plastic or foil.

4) Store items like flour and nuts in refrigerator, freezer or a cool, dry place. Warmth and humidity increase insect reproduction.

5) Keep storage areas clean and wipe up crumbs.

As mentioned, many of these insects can fly so seeing small, flying insects or a number of immature, crawling insects on or around boxes on shelves or in pots, pans, dishes or windowsills in kitchen or pantry, can indicate an infestation. Investigate for the source. If not found you will continue to see the insect. The source may not be in the kitchen. Don’t forget to check storage areas or dog, cat, bird or fish food. Once you find the source, discard the product. There is no way to save it. Check all other packaged foods for possible infestation and if free of insects, store in hard plastic or glass container.

Vacuum all crumbs of dry foodstuffs, especially around shelf edges, counters, floors, and behind appliances. Insect eggs and larvae may be difficult to see; some are microscopic. Follow by wiping with soap and water to eliminate spilled food residue.

Keeping your pantry products safe from these pests is a matter of prevention, exclusion and if infested, hard work. Unfortunately, lining your shelves with bay leaves or sticks of spearmint gum do not work for prevention or control. Also, spraying insecticide on the insect or in the cupboards will not help, and besides, chemical sprays are poisons, a health hazard and should not be used around food. However, if you do decide to use an insecticide, read and follow label directions.

Laura Murphy is a Master Gardener with Penn State Extension-Beaver.