There are three groups of beetles that can cause problems in a home. Carpet beetles will damage carpets, clothing, animal fur, feathers and similar products. Stored product beetles will infest many dried foods and wood boring beetles can damage the structure of a home or wooden objects in it.
Carpet Beetles (Dermestidae)
Carpet beetle larvae are small, about 1/4” long and carrot-shaped with long hairs. They will feed on anything organic. The adult beetles are small, round and usually black in color, sometimes with lighter markings.
The best method for controlling carpet beetles is by completely cleaning everything. Steam clean the carpets if possible as well as any upholstered furniture. Make sure you vacuum under all furniture as carpet beetles can survive feeding on dust bunnies. Keep a bottle of Greenbug for Indoors available to directly spray any adults or larvae you find. Make sure you vacuum up all the dead insects as the spines on the carpet beetle larvae can cause problems if they penetrate your pores as they can cause rashes.
Also, adult carpet beetles feed on the nectar in flowers so they don’t do any damage beyond breeding indoors. If you have flowers blooming near your house, you will attract adult carpet beetles. Make sure there aren’t any ways for them to get into your house.
Flour beetles (Tenebrionidae – Tribolium spp.)
Flour beetles are small, brownish in color and elongate in shape. There are nine species that are potential pests in stored food products. Two species are very common. The confused flour beetle (Tribolium confusum) is common in northern regions and the red flour beetle (Tribolium castaneum) is more common in southern areas. They feed on barley, beet pulp, breakfast cereals, grains, nuts, wheat, wheat bran, milk chocolate, dried milk and occasionally hides. Good sanitation is key to controlling these beetles. Freezing stored products at -4 degrees for 24 hours will kill all stages, as will heating at 122 degrees for an hour.
Drugstore beetles (Anobiidae – Stegobium paniceum)
These beetles have a hood-like thorax which hides the head when viewed from above. They are reddish brown in color and rounded in profile and oval-shaped. They feed on a variety of products including tobacco, seeds, grain, nuts, beans, spices, dried fruits and vegetables, flour, rice,ginger, yeast, herbs, paprika, dry dog and cat food, cocoa, biscuits, raisins, dates, alfalfa, hay, almond hulls, barley, corn meal, rice meal, wheat bran and even rodenticides. They are good at penetrating packaging to get access to food. The same control methods recommended for flour beetles will work on this species.
Saw-toothed grain beetles (Silvanidae – Oryzaephilus surinamensis)
Saw-toothed grain beetles small, black, elongate and have six distinct saw-like teeth on each side of the thorax. They are commonly associated with breakfast cereals and is frequently found in corn meal, flour, biscuit mix and processed cereals as well as in alfalfa seed, almonds, baking soda, barley, candy, clover seeds, chocolate, sugar, rice, wheat, cereals, dried fruits, corn, cornmeal, corn starch, flour, garbanzos, hay, honeycomb, milo, mixed feeds, oats, raisins, rice, figs, peas, pecans, dried meat and tobacco. Sanitation and freezing and heating will also work on these beetles.
Hide & Larder beetles (Dermestidae – Dermestes spp.)
Dermestid beetles are larger than other stored product beetles, reaching a 1/3 of an inch long. The hide beetle is brown on top and white on the bottom and the larder beetle is brown with a broad cream-colored band across the front of the abdomen. These beetles prefer animal products such as leather goods, hides, skins, dried fish, pet food, bacon, cheese and feathers. They can be a major pest in museums. Sanitation is important and sticky traps can be used on flat surfaces to catch adult and larval dermestid beeetles.
Weevils (Curculionidae – Sitophilus spp.)
Weevils are easily recognized by their small size and prominent snout. They are very destructive of stored grains in the world. They will feed on chick peas, corn, oats, barley, rye, wheat, kafir, buckwheat and millet. They are frequently found in macaroni and noodles. When you find any of these beetles in your home, inspect all open dried foods and toss anything that is infested. Place all non-infested foods in sealed containers or refrigerate them. Completely clean the pantry where the foods are stored to get any larvae that may be crawling around. Then lightly dust the shelves with food-grade diatomaceous earth before putting the foods back.
False powder post beetles (Anobiidae & Bostrichidae)
There are a number of species of beetles in this family that attack wood. They will attack new and old hardwoods and softwoods, with a 12% moisture content. They are recognized by their hood-like thorax that hides the head when viewed from above. They have a cylindrical body shape and are reddish-brown to brownish-black in color. They are often found infesting wood joists and sill plates in crawl spaces under homes. Two common species are the deathwatch beetle (Xestobium rufovillosum), the furniture beetle (Anobium punctatum). The furniture beetle will infest furniture and pine flooring.
Other beetles in these two families include the California deathwatch beetle (Hadrobregmus gibbicollis) which occurs along the Pacific Coast. Xyletinus pelatus (no common name) is found in the eastern United States and attacks cellar joists and flooring in damp buildings. Nicobium castaenum (no common name) is found in Virginia, South Carolina to Louisiana and attacks furniture and pine woodwork. The lead cable borer (Scobicia declivis) normally infests dead and seasoning oak and damage can be severe. It is found throughout the west and is most common in California.
The best method of control for all wood-boring beetles is to treat all exposed wood with a sodium borate, which will prevent them from reinfesting the wood after they emerge.
Powder post beetles (Bostrichinae; Lyctinae – Lyctus spp.)
Powder post beetles are small, elongate and almost always infest hardwoods. They frequently infest lumber, woodwork, furniture, tool handles, gun stocks and similar items. They produce very fine, powder-like frass when they damage wood. Frass from anobiids and bostrichids is not nearly as fine as these beetles produce. They are second only to termites in destructive capability. There are several destructive species nationwide. The brown powder-post beetle (Lyctus brunneus) found in most states and is frequently found infesting imported hardwood products. The western powder-post beetle (Lyctus cavicollis) is found throughout the the United States and attacks oak firewood and hickory, orange and eucayptus wood. The European powder-post beetle (Lyctus linearis) is found in the eastern United States and attacks hickory, oak, ash, walnut and wild cherry wood. The southern powder-post beetle (Lyctus planicollis) is found nationwide but does most of its damage in the southern states. It prefers seasoned or partially seasoned wood of oak, ash and hickory. The white-marked powder-post beetle (Trogoxylon parallelopipedum) is a common native species and has the same food preferences the southern powder-post beetle.
Long-horned borers (Cerambycidae)
Only a few species of long-horned beetles are pests of wood in homes. The old house borer (Hylotrupes bajulus) is probably the most destructive species in this family of beetles. It is found from Maine to Florida and west to Michigan to Texas. There have been some reports of this beetle in California. They are between ½ and ¾ inches long and are slightly flattened. They are brownish-black in color. Each wing cover has a gray band on it.
They are usually built into a house with wood from storage as adults have been found at lumber mills in seasoned and unseasoned wood. The frass is slightly granular and composed of small, barrel-shaped pellets of digested wood and irregular shaped wood fragments that were not eaten. The larvae can feed on the wood from 2 to 10 years before maturing into adulthood, depending on environmental conditions.
Metallic wood borers (Buprestidae)
The larval form of these beetles are called flat-headed borers, because the exit holes in the wood are oval, not round as in most other wood boring beetle larvae. Only a few species will attack seasoned wood, so they aren’t a serious pests. The adult beetles are often brightly colored and metallic. They are boat shaped in appearance. The most destructive species is the golden metallic borer (Buprestis aurulenta). The wings are greenish-blue with copper margins. They will attack flooring and woodwork of Douglas fir that isn’t finished with paint or varnish. They also feed on pine and spruce lumber. These beetles are found throughout western United States.