Grain Insects

Beetles and similar pests are known as “pantry pests” or “stored-product pests” since they infest these areas and feed on the foods commonly stored in these locations. These insects can get into even the most tightly sealed containers in your pantry to feed on the contents where they contaminate the food
  • Cigarette Beetles
  • Confused Flour Beetles
  • Drugstore Beetles
  • Red Flour Beetles
  • Rice Weevils
  • Sawtooth Grain Beetles

Cigarette Beetles

Appearance: Cigarette beetles are shiny and yellowish to reddish-brown in color. They are oval shaped and the head is bent downward sharply and often concealed by its head shield, when the beetle is viewed from above. The wing covers are smooth and they have serrated antennae.

Behavior: Cigarette beetles have a life cycle of 70-90 days, depending on the temperature. When fully grown, the larvae are c-shaped and covered with long hairs. They are known primarily as stored-food pests, feeding on common pantry items, and are known to infest dried tobacco and tobacco products, hence their name.

They prefer to reside in dark cracks and crevices and are most active at night. They are also strong fliers and can be a nuisance to homeowners by flying on windows and doors in large numbers.

Habitat: Aside from residing in dried tobacco and related products, Cigarette beetles are often found infesting raisins, figs, dates, ginger, wheat and wheat bran, beans, cereals, peanuts, dry pet food, dried flowers, leather and wool cloth, etc. They may also damage book bindings when feeding on the paste and on furniture stuffing.

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Confused Flour Beetles

Appearance: Confused flour beetles are flat, shiny, reddish-brown with an elongated body. Their antennae segments increase in size from the base to the tip to form a club that consists of four segments. These beetles cannot fly.

Behavior: Confused flour beetles are stored-food pests and infest milled grain products such as flour and cereals. They are often found on the surface or deep within the food material they are infesting, and can invade storage containers because of their small size. They are also common in warehouses and grocery stores, and can invade homes where dry goods are stored.

Female beetles can lay 300 to 400 eggs in flour or other food during a 5 to 8 month period. Their tiny eggs hatch into slender larvae that have a 2-4 month life cycle, with adults living 3 years or more.

Habitat: Confused flour beetles often hitchhike into the house in infested flour and can multiply into large populations on food crumbs that accumulate in cabinet cracks, crevices, and furniture. They breed in damaged grain and grain dust, flour, etc.

They can be found living in and feeding on barley, breakfast cereals, corn, cornmeal, flour, millet, rice, rye, wheat and wheat bran, dry beans, spices, powdered milk, and sunflower seeds. They also feed on dried fruits, nuts, chocolate, and other foods in the house. They have even been known to feed on arsenic-based insect and rodent baits.

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Drugstore Beetles

Appearance: The Drugstore beetle is brown to reddish-brown in color and is similar to the Cigarette beetle. It is more elongated in shape and their wing covers appear lined. Their antennae have three enlarged segments at the tip.

Behavior: The drugstore beetle is a common stored-food pest. Females lay eggs in various dry foods that have a life cycle of 2-7 months. Larvae form a small round ball or cell that becomes a cocoon in which it pupates. Adults live for approximately 2 weeks to 2 months depending on temperature and available food sources.

The Drugstore beetle can feed and survive on food and other items of no nutritional content due to internal yeasts they produce. It has been known to bore into books, wooden objects, and even tin or aluminum foil and lead sheets. They cause tremendous damage and economic losses by feeding on post-harvest and stored grains and seeds, packaged food products, and animal and plant-derived items and products.

Habitat: Drugstore beetles get their name from their habit of feeding on prescription drugs. They may feed on many drugs in the pharmacy, and often feed on poisonous rodent baits containing strychnine. They also infest almonds, peanuts, paprika, red pepper, cornmeal, flour, wheat and wheat bran, wheat germ, dry pet food, bread, birdseed, beans, coffee beans, pastas, powdered milk, etc.

Non-food items such as books, manuscripts, dried flowers, certain fillers and fabric coverings of furniture, wool, and leather may also be damaged by feeding Drugstore beetles.

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Red Flour Beetles

Appearance: Red flour beetles are reddish-brown in color with a flat, elongated body. They are very similar to the Confused flour beetle except the Red flour beetle’s antennae ends in a three-segmented club, whereas the Confused flour beetle’s club-like antennae has four segments.

Behavior: The Red and Confused flour beetles live in the same environment and compete for resources. They Red flour beetle can fly, especially before a storm. They can breed throughout the year in warm areas, with a life cycle that can take from 40-90 days. All forms of the life cycle may be found in the infested grain and stored food products both beetles favor. Adults can live for three years or so.

Red flour beetles can be found in large numbers in infested grain and pantry products, as well as in cracks and crevices where these products may have spilled. They are attracted to grain with high moisture content and can cause whatever foodstuff they are infesting to have a gray tint and can encourage mold growth.

Habitat: Adult Red flour beetles are very active and can be found either on the surface or deep within the food material. They are scavengers and must rely on other insects to damage grain before they can feed on it. Because of their small size, they are able to invade storage containers. They can be found in dry pet food, dried flowers, nuts, birdseed, meal, and most grain products.

Red flour beetles have chewing mouthparts but do not bite. They are attracted to light but will go towards cover when disturbed. They prefer temperate areas but can survive the winter in protected places, especially where there is central heat.

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Rice Weevils

Appearance: The adults are around 2 mm long with a long snout. The body color appears to be brown/black, but on close examination, four orange/red spots are arranged in a cross on the wing covers.

Behavior: Rice weevils are internal feeders. The female uses her strong mandibles to chew a small hole in a grain kernel, where she deposits a single egg in the hole and seals it with a gelatinous fluid. Rice weevils are active fliers and often fly to grain storage bins and buildings from nearby fields. When disturbed, Rice weevils play dead by drawing their legs close to their body. They then lie still for several minutes before resuming movement.

Habitat: Rice weevils are usually found in grain storage facilities or processing plants, infesting wheat, oats, rye, barley, rice, and corn. Although not often found in the home, they are sometimes found infesting beans, birdseed, sunflower seeds, dried corn, and too a lesser degree macaroni and spaghetti. Rice weevils do not bite, nor do they damage wood or furniture.

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Sawtooth Grain Beetles

Appearance: Sawtoothed grain beetles are reddish-brown in color. They are flattened and have six sawtooth-like projections on each side of the prothorax.

Behavior: The Sawtoothed grain beetle is a scavenger and can not fly. Adults and larvae are external feeders, feeding on finely divided food particles and not whole grains. Large populations of this beetle can develop quickly, forcing adult beetles to seek new food sources. They have been known to invade every package or food stored near an infested food product.

Sawtoothed grain beetle adults usually live about 6 to 10 months, with some living as long as 3 years. Females usually emerge in April and lay an average of 300 eggs. Egg laying begins about 5 days after emergence and continues up to 3 to 4 weeks. Eggs hatch in about 8 days, larvae mature in 37 days, and pupa about 67 days. They prefer cereal-based products.

Habitat: The Sawtoothed grain beetle is common in stored-food products such as cereal, cornmeal, cornstarch, popcorn, rice, dried fruits, raisins, flour, pet foods, bran, macaroni, sugar, and bread. They are capable of chewing into unopened paper or cardboard boxes, through cellophane, plastic, and foil wrapped packages. Once inside, populations build up rapidly often spreading to other stored foods and into food debris accumulated in the cupboard corners.

Bugs.com . “Bugs Database.” Grain Beetles (2011):  Web. 27 Jul 2011.

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If you live in South Florida Pro Pest Control can handle all of your potential problems so contact us if you have any questions and be sure to receive your free estimate.
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