Stored Product Pests

Imagine pouring yourself a bowl of cereal, just to witness a small, moth-like insect fly out. It could be an Indian meal moth, a common insect that infests kitchens and pantries. Many common insects that infest food in kitchens and pantries are known as pantry pests, or stored product pests.

Pantry pests are commonly found in and around kitchens, infesting stored grains, flour, dried fruits and spices. These insects can be observed crawling in kitchen cabinets or flying near well-lit areas such as windows. Not only are these pests disgusting and annoying, but they can destroy food as well. Some of the most common stored product pests are:

The Indian Meal Moth (Plodia interpunctata)

This moth is perhaps the most common among stored product pests in the United States. The adults are excellent fliers, hence they are found everywhere in the house and kitchen and disperse easily. They are bi-colored, short lived and are active at dusk. The young are commonly found in the kitchen cupboards where they infest the food items. Adults are 5/8 inch long which produce visible silk webbing on the infested host. They pupate in the tight crevices within cupboard or ceiling and the liner of the storage box/container. Food can be contaminated by Indian meal moths as they produce webbing in the food. The female can lay hundreds of eggs, leading to a large infestation in a short amount of time. The moth takes 4 weeks to complete its life cycle.

The Sawtoothed Grain Beetle (Oryzaephilus surinamensis)

The brown, ?-inch slender and minute adults of the sawtoothed grain beetle can be identified best by using a hand lense. The beetle received its name because of its six saw-like teeth located on its thorax. The adult lays up to 300 eggs on the host and larvae feed on either grain powder or grain embryo. The full-grown larvae pupates itself in the cupboard crevices and cracks. It emerges into adult within a week. They complete a life-cycle in only three weeks. Considerable damage can result in cereals, bread, pastas, nuts, numerous grains and more from sawtoothed beetles.

The Red Flour Beetle (Tribolium castaneum)

This beetle is commonly found in kitchens and stores. As its name suggests, it infests and ruins flour, but also infests grains, nuts, peas, spices and fruit. This reddish-brown beetle is about three millimeters long, and can lay up to 1,000 eggs throughout the flour. The cream-colored larvae feeds on grain dust or damaged grains. The total life-cycle may take up to 1 month in summer.

The Rice Weevil (Sitophilus oryzae)

The adult weevil is about 1/8 long with a snout and club-like antennae on its head. Female lays up to 450 eggs. Eggs are laid in whole kernel grains by chewing up a depression in kernel, laying egg and then plugging it with gelatinous secretion. These eggs hatch into legless larvae which consume the inside of kernel. The larvae pupate within the grain. When adults emerge out of the grain, it eats up the grain and makes “exit holes” which is a characteristic sign of damage. The adults are good fliers and can be observed in the other parts of the house other than the kitchen.

The Drugstore Beetle (Stegobium paniceum)

The drugstore beetle received its name because it was discovered infesting areas that contained medicines and herbs; it was also found in drug stores. They commonly infest grains, flour, bread, dried foods and spices. The head of the adult is covered by pronotum and thus not visible from above. It is short-lived and can undergo several generations per year. The adults are good fliers and fly towards light. They can be observed flying or sitting near lighted areas such as windows.

Controlling Pantry Pests

The first step in controlling stored product pests is to first identify the pest. Not all stored product pests are controlled the same way. A pest management professional can help identify the insect. Additionally, most pest control companies offer free inspections and identification.

Second, try to identify the source of the infestation, then remove the source. Someone with an Indian meal moth infestation may find the source of the problem in dog food or bird seed. However, because finding the source is not always easy, a pest management professional can help in this area as well.

To help prevent further infestation of stored product pests, one might place food in tightly sealed containers to prevent the insects from infesting the food. Control methods may involve the use of pheromone traps, sanitation or chemical control. This is when consulting with a pest management professional is necessary, as they know the best control methods for each of the various pests.

Interesting facts:

• The Indian meal moth is also known as “North American highflyers,” and is also It a cousin of almond moth.
• Drugstore beetles are known as the “biscuit beetle” in the United Kingdom. It is named so because the drugstore beetle was found to infest medicinal herbs used in drugstores.
• The rice weevil is native to India but is now found everywhere in the world because of commercial trade.
• The Latin name of saw-toothed grain beetle “Oryzaephilus surinamensis” comes from the word “Suriname” which means “rice loving”.