Powder post beetles.
The larvae of these beetles feed on cellulose in the wood and they can cause extensive damage to wood in structures and homes if conditions are suitable to them. Moisture plays a key role in attack from these insects. Losses are often heaviest in warm humid climates, but some species occur throughout the United States. in their feeding they often reduce the wood to a fine powder, not unlike talcum powder in consistency. Holes are often about 1/8 inch in diameter and round. They are sometimes called "shotholes". You may want to use a tool such as an awl to see how much damage there is. if the awl pokes in easily and deeply the wood may be severely damaged.
Eggs are deposited in cracks, crevices, pores or old emergence holes in wood, or in tunnels made by the females. A tiny larva hatches from an egg and burrows into the wood. It continues feeding and growing to maturity when it burrows toward the surface and pupates. The adult emerges from the pupa and continues the tunnel to the surface. Adults leave the wood, mate, and then the females return to lay eggs. Exit holes and sawdust from beetles burrowing out are often the first symptom noticed.
Depending on the type of powder post beetle and the species, the life cycle may range from 3 months to 2 or more years. Some species are specific as to the types of wood they infest, while others are general feeders. However, they usually are either hardwood or softwood infesters.
The first step to management is deciding if there is an active infestation or if you are seeing old damage. in an active infestation, look for borings accumulating in piles near holes or on the floor below, beetles crawling on the wood, or you may hear a ticking sound that is made by some larvae. If there is no active infestation, treatment is not needed.
For small infestations, removal of the infested item or replacement of infested wood may be all that is needed. in moist areas pressure treated wood should be used.
If you have a severe infestation professional control may be necessary. It may also be necessary when the infestation is very wide spread, or it is hidden behind paneled or plaster walls or in other hard to reach places. If wood is badly damaged and its structural strength is impaired it should be replaced. Fumigation may be necessary in some cases, either for individual pieces of furniture or an entire structure. Many pest control firms have fumigation facilities for items such as furniture.
Where excess moisture is a problem, all efforts to correct the cause should be undertaken. It does, however, take wood a long time to dry out, and reducing moisture may not be enough to control powder post beetle infestations.
Some powder post beetles lay their eggs in the pores of unfinished hardwood. Hardwood items are often finished with paint, shellac, varnish, sealer or wax and are therefore safe unless some bare wood is left exposed. if you find beetles emerging from finished hardwood, the infestation was most likely there before the finish was applied. Applying finish to wood can help deter infestation because the beetles are not able to deposit eggs on finished surfaces. However, if beetles are emerging from a piece of furniture or wood, the exit holes provide spaces for the female beetles to oviposit in again.
For small items freezing or heating may offer a possible solution. CAUTION: Heating or freezing may have detrimental effects on some finishes and may cause shrinking or warping of the wood itself. Placing small items in a deep freeze for four days or longer should kill larvae and eggs. A refrigerator freezer does not get the temperature low enough to give control. Heating in an oven until the temperatures reach 120OF and keeping them at this temperature for 30 minutes will also control eggs and larvae.
Exposed wood under crawl spaces may be infested by beetles flying into the area and over positing on the wood. Where damage is severe, replace with pressure treated wood.
Species attacking softwoods or hardwoods indoors are usually brought into the house in wood or furniture which contains eggs or larvae. Remember, the beetles attack either hardwoods or softwoods, but not both.
Use kiln dried wood in construction. Examine lumber for infestations before use. Repaint and refinish surfaces after a beetle emergence. insects seldom reinfest dry refinished wood.
Deodorized kerosene can be brushed or sprayed on some surfaces and will provide some control. It is a flammable material and should not be used where there are any open flames. Do not smoke, shut off pilot lights and provide plenty of ventilation. For cabinets and furniture take them out of doors to treat and leave them there until the kerosene odor disappears.
For all treatments it is recommended that you remove the finish before treating. For larger areas, such as floors, use only enough material to wet the surface of the wood, keep doors and windows open; and if necessary use a fan to prevent odors from accumulating in the window. Removal of the floor finish before applying the kerosene allows the wood to absorb most of it. if you need to treat a parquet floor, do it very lightly, otherwise you might dissolve the asphalt in which the floor is set and staining or "creeping up" of the floor could occur. it is recommended that you wear rubber gloves, and a rubber or leather apron. When spraying an overhead area, do not stand directly under it!
Prepared by: Carolyn Klass, Senior Extension Associate Department of Entomology, Cornell University (Reviewed 1986 - reprinted 1994)
Reviewed by: Dr. Larry Abrahamson and Dr. John B. Simeone, Department of Forest Biology
SUNY College of Environmental
Forestry and Science
Syracuse, New York 12233
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|Publication:||Pamphlet by: Cornell University Cooperative Extension|
|Date:||Jan 1, 1994|
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