Bakers in the family and everyone else who enjoy the benefits really like the holidays. Lots of cookies, cakes and pies are baked during the holiday season. It is not the baked goods that will give households any problems, but what comes later with the leftover flour.
Pantry pests are those tiny grain beetles and flour moths live in and feed on the leftover flour. This phenomenon is not uncommon as many homes do not routinely bake during other times of the year. The left over flour products naturally get pushed to the side or back of the pantry or kitchen cabinet and forgotten over time.
The most common and easily discovered pantry pest is likely going to be the Indian Meal moth. As the name suggests the adult flies and is often found near windows or more often flying around light fixtures in the kitchen area. If you find the moths, then for sure there is a product that contains flour or left over flour itself has been supporting these pests. If the Meal moth has been in your white flour, the color becomes a dingy grey and there will also is webbing found in the container. You will see larval stages in the product as well. Once the larvae have grown large enough they will crawl out of the infested product and find a crevice to pupate and turn into the adult moth. Once mated, the adult will return to a food source and lay more eggs to repeat the cycle.
Management of the Indian Meal moth and the flour beetles mean finding the source of the infestation. If caught early this could be just that left over flour. If left for a while it could be any product that contains a flour or grain. Any highly processed product would not be the initial source, but could easily become contaminated later. If the outbreak is substantial, every product become suspect and will require lots of time and effort to deal with the moth. The remedy for the moth and beetles is to inspect all packages in the cabinet and throw away any clearly infested products. Any products left should be considered suspect and placed in a tight sealing container in the pantry. Later if another product is found with the insects, you only have to discard the one product and not inventory the entire pantry again. There are no insecticides to spray. Cleaning and vacuuming the pantry shelves and removing any shelf paper will expose areas where pupation can occur. Be sure to clean the entire cabinet, including the cabinet cracks and crevices above your head too! This will lessen the adult populations that would be emerging later.
As you buy new products for the pantry, only buy the amount you will use in a short time.
Do not buy products that are in a broken or damaged bag or box. Other considerations would be to remember to rotate and use older products first and to keep the pantry free of spilled food and crumbs. If you are going to keep ground flour products after the baking season, consider putting them in the refrigerator or freezing them till you bake again. It is always easier to prevent these insects now than having to clean up their mess later.
About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.