POWDERPOST BEETLESTYPES AND BIOLOGYPOWDERPOST BEETLE INSPECTIONPREVENTION OF WOOD BORING BEETLESRECOMMENDED MEASURES OF CONTROL |
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The larvae of these beetles reduce timbers to a mass of very fine, powder-like substance. The adults do very little damage . In this section we will discuss four types of Powderpost
beetles in four families: Lyctidae, Bostrichidae, Anobiidae, and Cerambycidae.
Adults do little damage, it is the larvae that does the major part of
the damage.They go through a complete metamorphosis: adults, eggs, larvae
and pupae.
True Powderpost Beetles(Lyctidae):
The adults are very small, less than 1/4" in size. They are flattened and reddish-brown to black in color. Larvae are white, cream colored, shaped with dark brown heads. Larvae create tunnels in the wood and become pupae. As adults they bore out through the wood, pushing a fine powdery dust out.The shape of their holes are round ,about 1/32-1/16 pinholes. They attack hardwoods depositing their eggs. True Powder post beetles breed in dead and dried hardwoods such as the dead branches and limbs of trees. Their presence is overlooked until they are discovered in stored lumber, rafters, joists, finished wood, and furniture products. As a rule, they enter lumber while it is being stored and cured, then later, emerge from the finished product. Old items of furniture and wood antiques are especially vulnerable to attack by the beetles. Damage is usually Their diet is starch, sugar and protein in the sapwood of hardwoods Wood that
is less than 6% moisture content is seldom attacked .The life cycle
averages one year to complete .This wood-boring beetle is the most widespread
in the United States. Many times infestations are built into structures
from infested lumber .They can re infest. Lycid damage is characterized by: Recently formed holes and frass(sawdust like)
are light in color and clear in appearance....old holes and frass
are dark in color.
False Powderpost Beetle(Bostrichidae)
They are larger than other families of powderpost beetles ,so their exit holes are larger. These holes do not contain frass,but the galleries do. The frass is tightly packed, tends to stick together and is meal like( contains no pellets) The adults are 1/8-to 1-inch long, cylindrical, and reddish brown to black. The adults bore into the wood in order to lay eggs, leaving a hole larger that 1/8 inch, usually in wood less than 10 years old. The larvae are curved and wrinkled. Their diet is dependent on the starch in the wood, they are more common in softwood ,but can attack hardwoods. They require 6-30% moisture content in the wood, and complete the average life cycle in one year. Most of the hardwoods attacked are not those commonly found used for interior floors,woodwork or trim. Most of this species does not re infest wood after it is seasoned, so the damage is limited to that inflicted by one generation. However the speed of the damage can be considerable. Most of the time they do not re infest wood after
it has been seasoned. They are often found in oak, firewood and
furniture. Anobiid Powderpost Beetle (Anobiidae)- Furniture and Deathwatch Beetles
The furniture beetle is found mostly in the eastern half of the United States and it infests structural timbers as well. The Death-watch beetle is found throughout the United States. It attacks building timbers in poorly ventilated areas where moisture tends to collect. The name"Death watch" comes from the ticking sound that the adult makes inside infested wood that is audible during a still night. It is a mating call. The insect is a common pest in the southeastern United States in crawl space timbers. Infestations can become so severe, that loss of structural strength to sills , joists, and sub flooring occurs. Various anobiid beetles attack seasoned wood in the United States. These beetles range in size from 1/32- to 3/8-inch long; however, those that attack structures are 1/8- to 1/4-inch long. They have highly variable body forms but most are elongate and cylindrical. The first body segment (pronotum) is hood-like, hiding the head when viewed from above. The last three segments of the antenna are lengthened and expanded into a club. The mature larvae are as large as 1/2-inch, C-shaped, dirty white, and the area behind the head is expanded and swollen.The larvae are slightly curved and wrinkled, with tiny hairs on the body. The last spiracle on the abdomen is not enlarged. The furniture beetle, Anobium punctatum, is 1/8- to 1/4-inch long, cylindrical, and red-brown to dark brown in color. It has a series of pits in rows that run lengthwise on the wing covers. The pits can be seen through the fine yellow hairs that cover the body. The last three segments of the antenna are longer than the first eight combined. The adult deathwatch beetle, Xestobium rufovillosum, is 1/4- to 3/8-inch long and is gray-brown with patches of pale hairs on the back of the body. Deathwatch Beetle Click to Enlarge CREDITS: University of Florida It does not have the rows of pits on the wing covers and their
11-segmented antenna end in three elongated segments that are
as long as the previous five segments. The larvae form tunnels in both softwoods and hardwoods They require 13-30% moisture content. Their holes are round,1/16-1/8 inches. They can digest cellulose from the wood. They are inclined to the softwoods ,for this reason they are common in crawl spaces and basements ,infesting the pine used as framing lumber. The powder outside the holes (frass) is fine to coarse, many times with small pellets. The life cycle averages 1-3 years. They commonly re infest crawl space areas that
are poorly ventilated and humidity is absorbed in the wood. These beetles commonly infest seasoned sapwood of hardwoods and softwoods; they are rarely found in heartwood. They attack structural timbers, lumber, cabinets, and furniture. These beetles re-infest, and the females commonly lay eggs in the wood from which they emerged. The larvae typically follow the grain of the wood when feeding ad fill their tunnels with wood frass. The frass is a fine powder with long pellets loosely packed into the galleries.
The surface of unpainted or otherwise unprotected wood can be
treated and the galleries injected with disodium octaborate tetrahydrate
such as BoraCare or Timbor.
Most representatives of this family infest and feed
on dead or dying trees. However there are many that feed on living
trees. There are some of these species which begin their development in dying trees, logs, or unseasoned lumber and then complete the development as the wood seasons. A common source for these beetles indoors is from firewood brought indoors. A sighting of these beetles can lead to a false assumption of a structural attack. Firewood that is brought in , should be used very soon after it is brought inside. The beetles of this family lay their eggs in cracks or crevices in the bark or on the surface of rough sawn timbers. The larvae are wood borers. Mature larvae are large, varying from 1/2 to 3-4 inches long. The body is long and narrow and a light cream color. The rear portion of the head is partly drawn into the body so that only the mandibles and other mouthparts are easily seen. Adults vary in size from 1/2 inch to 3 inches long. They can be easily distinguished from other beetles by their long, thin antennae which may be longer than the body; hence the adults are called long-horned beetles. The adults of these boers will emerge from the wood after it has been incorporated into a structure. They will not re infest the wood because of its dryness, but they are of great concern to property owners who find them or evidence of their activity. Old House Borer(from the family Cerambycidae)
The Old House Borer is one of the most common from this family, with it's larvae hollowing out galleries in seasoned softwood(pine). It is found in older buildings, but is more frequent in newer buildings,(in houses less than 10 years old). It is well established along the Atlantic Coast, but infestations have been reported as far as Louisiana and Minnesota. The adults are brownish-black to black, slightly
flattened and about 3/4-1 inch long. This , along with the fact that larvae will do extensive feeding without breaking through the surface of the wood, make it necessary to inspect infested wood very carefully to detect old house borer damage. Rough wood being examined should be probed or struck to detect weakness or the presence of boring dust. If exit holes are present, they will be broadly oval and about 1/4-3/8 inch in diameter.
The life cycle of the old house borer ranges between three to twelve years, but can be last longer if conditions are favorable. Because of the long life cycle, re infesting the wood it may take years before you see any structural damage . The exit holes are about 1/4-3/8-inch in diameter, but damage may have occurred for several years before spotting such holes. They are able to digest cellulose. When wood has been infested with fungi, the larval
development is faster. Their powder (frass) in the tunnels are
like sawdust ,tightly packed. 
Click to enlarge Photo courtesy of IPM Alabama 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 or 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. PREVENTION OF WOOD BORING BEETLES Steps to prevent beetles from infesting wood include:
CONTROL AND RECOMMENDATIONS: The following points should aid in discouraging powderpost beetle infestations: 1. The first thing to do is reduce the moisture content, to a proper
ventilation to less than 20%.Moisture meters can be used to determine
the moisture level in the wood. Central heat,vapor barriers and good
ventilation can help control moisture.
Rough-cut lumber should be kiln-dried to kill all stages of the
beetle.
Reducing moisture however ,may not be enough to completely control powder
post beetle infestations. 2. Un infested wood which is sanded and varnished will not normally be attacked by the adult beetles because they cannot find crevices in the wood surface into which they would deposit their eggs. 3. Items of value should not be stored in out buildings such as barns and sheds. These buildings are often infested with wood-boring beetles. 4. Infested furniture can be fumigated in a fumigation chamber. Only pest control operators licensed to do fumigations are permitted to purchase and use these materials. 5. Surface sprays containing borates will prevent newly hatched larvae from entering the wood. However, this technique is not effective on wood which has been varnished, waxed or otherwise sealed from attack by moisture. 6. If practical ,remove infested wood. If not,use residual borate insecticides. TIMBOR is a powder that mixes with water. One lb.is mixed with one gallon of water and sprayed to the surface area of in infestation. When sprayed it penetrates the entire wood, where it will remain for several years .An alternative to Timbor is: BORACARE.
Boracare is a liquid borate that penetrates faster initially
than the Timbor for first few hours but is equal after that..Timbor
is considerably cheaper per gallon use.
7. Fumigation may be advisable in cases of severe |
