by David Moore
Manager of Technical Services and Board Certified Entomologist
with contributions by Eric Smith, PhD, BCE
As the holidays approach, more and more people will be cooking for family gatherings and discover new friends in their pantry. Discovering bugs in your food may seem disgusting, but it isn’t unusual. I want to take a moment and explore what some of those pests are, what they can do, and some methods that can be used to eliminate them. There are many types of pests that can infest our food, but we will only concentrate on a few of the most popular pests that are found in our stored food items.These pests can include small beetles, moths, and worm-like creatures that can cause a person to have an intense reaction to even see inside their food products. Several of these pests are pictured in the Dodson Pest ID Guide elsewhere on this web site that Dr. Smith had created.
How do we get these pests?
These pests are usually brought into the home in food items purchased at the grocery or pet supply store. These pests can be successful just about any place that bulk foods and pet food and supplies can be found. This does not mean that these locations are dirty or unsanitary. Usually these stores will receive product that is already infested without their knowledge. Most of these stores have pest management services that will respond when alerted to the issue to eliminate the problem.
What are these pests?
Indianmeal moths: In the United States, the Indianmeal moth is the most common of the stored product pests found in homes and grocery stores. It can take about 25 days for the eggs to hatch, the larvae to become full grown and pupate, and for the adults to emerge given the right environment. The mature larvae leave the food source and wander about to find a suitable pupation site. Indianmeal moths feed on a large variety of stored food products, but home infestations often get started through dried pet food or birdseed. Nuts are a favorite breeding source
Warehouse beetle: The major concern with warehouse beetles is their larvae are covered with hundreds of sharp hairs. If larvae and/or larval molt skins are not detected in food product that is eaten, severe gastrointestinal problems can result. Infants are at a higher risk for this pest affecting them. Warehouse beetles are common outdoors and readily feed on dead insects such as those found on windowsills and along baseboards, and from here adults move to lay their eggs in available stored food items.
Flour beetles: There are a number of species of tiny beetles that infest flour, but the two most common flour beetles are the confused and red flour beetles. Both are reddish-brown and about the same size, 3/16-inch long and can only be distinguished apart from each other by their antenna. They are commonly found feeding on flour, cracked grains, cake mixes, beans, peas, dried fruits, nuts, chocolate, spices and tobacco. They are usually discovered when someone opens a bag of flour and discover little beetles inside the unopened bag. These beetles can discolor the flour as they feed on it, and if allowed to perpetuate for a long enough time, a displeasing smell can develop.
How can we prevent getting these infested items?
Only purchase packaged foods that are not damaged and seals are intact. Purchase food in package sizes that can be used up in a short period of time. Use a “first in, first out” approach to food usage. This means to use older product before opening new items, and to use opened product before sealed product if possible. Store dried foods in insect-proof containers such as plastic or glass containers. This will help contain any infestation and help prevent the situation from spreading to other food items. Keep your food pantry clean and do not allow crumbs to build up, as exposed food will attract insects.
What should we do if we do find infested product?
Inspection and identification of all potential food sources is essential to controlling the infestation. Infested material should be immediately discarded, used up, or somehow treated to de-infest. Most people just throw away the products that they believe to be infested. When they find the infested product, it makes many people begin to question the rest of their food in their pantry. Additionally, if the situation has been going on for some time there is an odor which can occur that will turn some stomachs. Until the problem is resolved, I usually recommend that susceptible foods be stored in sealable containers to contain the issue and help reduce its spread. Food may also be stored in the freezer during this time frame. After about 3-4 days, all the pantry pests would have been killed inside the frozen products.
Thoroughly vacuum cupboards or shelves holding infested items. Make sure you pay particular attention to the cracks and corners. Vacuuming will suck up many of the pests and any infested material. Make sure you empty the vacuum cleaner or discard the vacuum cleaner bag after use to prevent re-infestation or spreading the problem to other areas of your home.
If you cannot eliminate the issue with these steps, you may have a more ingrained problem than you think. I would recommend calling a pest management professional to take a look at the problem and determine the best treatment methods. In some cases, no chemicals are needed and pheromone traps are sufficient to resolve the infestation.