If you have ever wondered who’s eating the cereal, these common pantry pests might be the culprit. Pantry pests are not dangerous to humans, although you might be grossed out if you happen to notice them after you finished your bowl of wheatie-o’s. These types of pests are not poisonous, they do not bite, or sting and typically do not cause harm to the home, except for the cost of replacing the goods infested. However, some sensitive individuals may find allergic reactions to some. The most common pantry pests are weevils, moths, and small beetles. Mice can also chew through boxes and thin plastic or foil bags to get to your dry pantry goods as well.
Pantry pests are those annoying insects that you find in your cupboards crawling around in the flour, cereal, rice, and other stored dry goods. They can also be found in beans, spices, and dried fruits as well. Other common items susceptible to infestation are dry cake mixes, nuts, chocolate, seeds (which includes popcorn) as well as cookies and crackers. Pet food can also be vulnerable to pantry pest infestations. Open containers are especially susceptible to pantry pest infestations because of the ease of entry. It is always best to store foods with airtight lids to prevent pests from seeking out your pasta.
Pantry pests come from a variety of places. They can enter your home from the outside, but most often they are brought in from grocery stores. However, these types of pests can happen anywhere dry grains, or goods are stored. From the silo on the farm to your home, these pests can take up residence in food products and accidentally make their way into your kitchen cabinets.
Common Pantry Pests
There are several types of beetles that any Florida home dweller might find in their pantry. These include the Flour Beetle, Cigarette and Drugstore Beetle, Warehouse Beetle, and the Flat Grain Beetle. In the US, there are two species of flour beetle, the red flour beetle and the confused flour beetle. These two beetles are remarkably similar in appearance. The red variety is much more common in the Southern United States as it prefers a more temperate climate. The confused species is more often found in the Northern United States as it favors a cooler climate. Flour beetles can attack their namesake but have also been found in nearly all dry stored goods such as chocolate, nuts, seeds, cereals, grains & rice, beans, and even pet food. These beetles are reddish-brown and about 1/8” long. The larvae are white or yellowish, with two small red protrusions on the tip of the abdomen. Larva can grow to about ¼” long before pupating.
Cigarette beetles and Drugstore Beetles are another species named after where you are likely to find them. Cigarette beetles are most often found in tobacco and similar products, while drugstore beetles are prone to attacking prescription drugs. However, it has been said that a drugstore beetle will eat “anything but cast iron.” This species of beetle is quite adaptable and can find nourishment in the most unlikely of objects. They have been noted feeding on many common stored goods, as well as prescription drugs. Drugstore beetles can also thrive on various plant materials such as wood, leather, books, and even museum specimens.
In some cases, they have even been found to feed on aluminum foil and lead sheets. Like the flour beetle species, the drugstore and cigarette beetle are incredibly similar in appearance. They are roughly 1/10” long and are uniformly red or brown. Larvae are grub-like in appearance, white in color with tiny hairs covering their bodies. The main difference between these two beetles are the antennae. The drugstore beetle has saw-toothed antennae, while the cigarette beetle’s antenna has three distinct segments.
Another namesake beetle is the warehouse beetle and its cousin, the larger cabinet beetle. These two beetles are like the carpet beetle in appearance and size. While the carpet beetle eats mostly wool and woolen products, the warehouse and cabinet beetles can be found feeding on most of your pantry products. Warehouse beetles are oval-shaped, about 1/8” long, and their coloration is red to brown with various patterns appearing on the back in light yellow to white.
Mealworms are not worms but are the larvae form of darkling beetles. These insects are likely the easiest of the pantry pests to spot, due in part to their size. At nearly 1.25” the adult insects are shiny black with well-developed wings that enable them to fly. They are attracted to high moisture milled grains such as wheat and oatmeal. They are also attracted to light. Mealworms are popular among reptile owners as several species of lizards and snakes feed on them and they are easy to keep, without the smell associated with other feeding insects. In your pantry, however, they are less attractive feasting on your grains, vegetation, and spoiled food. The larvae are pale brown in color, short and fat. Mealworms are also gaining popularity for human consumption because of their high protein content.
Another species of pest that is similar but separated by geographic region is the rice weevil and the granary weevil. Rice weevils are much more common in the Southern United States. North of Tennessee and North Carolina, the granary weevil becomes the dominant species, preferring the cooler temperatures. Rice weevils are one of the most notorious of the pantry pests. They have spread through commerce from India and are worldwide in distribution. Rice weevils tend to infest whole grains such as wheat, corn, rye, barley, and oats. They also can be found in cereals, wild bird seed, dried beans, and cashew nuts. However, they are most notorious for infesting macaroni products, as this is primarily where the females like to lay their eggs. They are reddish-brown to black with four distinct yellow or red markings on their forewings. They have an extended snout, nearly 1/3 the length of the entire body, which is only 1/10” long. Larva have no legs and are found inside the hollowed-out portion of macaroni or grain kernels. They are rotund with white to cream-colored bodies and dark heads.
The Sweet Potato Weevil is a significant pest of sweet potato plants. Entomologists find this insect fascinating because of its remarkable color pattern and extremely long beak. Like the rice weevil, the sweet potato weevil has a noticeably long beak. The coloration of this insect is a black beak with a red thorax and a metallic blue abdomen. Sweet potato weevils are about ¼-1/3” in length and have an ant-like appearance with a rounded abdomen and long thin legs and thorax. The beak is slightly curved at the end and is as long as the head and thorax combined. Sweet potato weevils have been known to decimate up to 97% of crops in the field where infested, causing significant economic impact on yields. They were first discovered in Florida in 1878. Sweet potato weevils are so named for their preference for this plant though they have been known to infest both railroad vine and morning glory plants. You can notice infested plants by noting those with a spongy feel and dark appearance. This damage is caused by the larvae burrowing inside the sweet potato for feeding, causing massive structural damage and leaving cavities riddled throughout the plant. Sweet potato weevils are one of the few pantry pests that can introduce disease, as feeding larvae often introduce soil-borne pathogens to the plant.
Bean weevils mainly attack dry beans and peas. They are olive in color with darker mottled spots on their back. They are less than 1/5” in size and are a rounded triangle shape. These are field pests that can be transferred during harvesting, shipping, and storing of products. They cause damage to the interior of the bean. The eggs are laid inside the pod. Larva feeds on its innards, devouring most of the contents.
There are two types of moths that you may find roaming your kitchen looking for a meal. They are the Grain Moth, and the Indian meal Moth, otherwise known as the Flour Moth, due to their food preference. With a wingspan of about ¾” the Indian Meal Moth has coloring similar to Indian corn with tan, copper and dark brown. From the base covering about 2/3 of the wing, they are solid tan. The edges are a coppery tone, usually with two horizontal dark brown stripes. One of the most common pantry pests is the Indian meal moth. They can be found attacking grains, nuts, pet foods, cereals, and many other dry goods. Indian meal moths are the number one pantry pest problem. Florida has an ideal climate for populations to thrive, making them one of the most prevalent pantry pests in the state. Indian meal moths can easily be spotted because of their web-like cocoons. They can create these cocoons anywhere and have been found on cans, plastic wrapping, Styrofoam, and other non-edible sources.
The Grain Moth, on the other hand, is singularly colored, ranging from cream or gray to darker browns and reds, depending on species. These moths attack cereal, pasta, flour, dried fruits, dried flowers, spices, and nuts, among others. Like the Indian meal moth, their cocoons are also webbed and can be found on a variety of surfaces. Both moths are most often introduced into the home through transportation from infested areas. Infestation happens when the cocoons hatch inside your home.
What happens if I ate contaminated food?
All of these insects are relatively harmless. None are poisonous to humans, none bite or sting. The only pantry pest insect to worry about might be the sweet potato weevil as they can transmit soil-born pathogens into the potatoes. However, if you are not eating the infested sweet potatoes, you should be fine. Other than the nausea associated with learning you may have just eaten a bug; swallowing a specimen or two of these insects is not going to make you sick.
How to get rid pantry pests
If you find that you have contaminated food, the best course is to find the source of the infestation and remove the food from your pantry. There are two methods available for treating contaminated food. Still, the best practice is just discarding any infested food sources. Make sure to do a thorough inspection and rid your cabinets of contaminated or potentially contaminated food stocks. The next step is to thoroughly clean all areas of your cabinets to remove potential pupal or larval stage insects. Remove all food from the infected area and vacuum all the shelves. Make sure to get into cracks and crevices as well, since many of these insects can feed on trace amounts of food. Next, remove any paper linings in the pantry and wash down each shelf and wall with warm soapy water. Do not use chemicals to treat areas where food is stored as this can contaminate the food after it is put away again. Throw away any products with signs of infestation or tampering by insects. Re-line your shelves with fresh lining and restock your cabinets.
If you must save a food item, you can kill off remaining pupal or larval stage insects with one of two methods. The first is heat; the second is cold. For the heating method, first spread the contents into a shallow baking pan or cookie sheet. Heat for thirty minutes at a minimum temperature of 130 degrees Fahrenheit. This method should kill off most of the remaining insects. To freeze, place food items in a sealed container and place it in the freezer at 0 degrees Fahrenheit for a minimum of 4 days. Ideally, you’ll want to wait a week before removing items as you’ll want to be sure to freeze to the center for several days. Again, this method should kill off most of the insect population. Still, it is highly recommended to simply discard any contaminated items and start fresh, as you don’t want to risk re-infesting your cupboards.
How to prevent pantry pests
When possible, always store your food in sealed containers made of heavy gauge plastic or glass containers with airtight lids. Any products that are stored and kept for a long time, such as sugars, flours, and rice or beans should be sealed, even if unopened, when brought in from the store. If you unintentionally bring home unwanted pantry guests, this practice will prevent the infestation from spreading. Sealing insects within a second airtight container prevents them from spreading to other goods.
Pet food and wild bird seed are particularly susceptible to pantry pests as most people do not store these products in sealed containers. Keep your pet food fresh for longer and prevent your beloved pets from ingesting these insects by investing in airtight containers for their dry foods.
Keep an eye out for caterpillars on windowsills, counters, and within your pantry. These are almost always indicative of a more significant problem. Use sticky traps to track down the shelf with the insect infestation. With a little foresight, some proper planning, and some investment in suitable plastic containers and resealable plastic bags, you can prevent pantry pest infestations.
University of Florida-IFAS: https://edis.ifas.ufl.edu/ig095, http://entnemdept.ufl.edu/creatures/urban/stored/drugstore_beetle.htm, http://entnemdept.ufl.edu/creatures/urban/beetles/red_flour_beetle.htm, https://edis.ifas.ufl.edu/in154, https://edis.ifas.ufl.edu/in027
Horticulture and Home News-Iowa State University: https://hortnews.extension.iastate.edu/warehouse-beetle-and-cabinet-beetle
University of California-Integrated Pest Management Program: http://ipm.ucanr.edu/?src=www2