Ask The Experts
Wood Destroying Insects and Pests
We are wondering how to get rid of bats. They are living under our cedar shakes, and they are living in the gable vent of the garage and in our metal chimney pipe.
We'll bet that you live near the river. Bats congregate wherever insects are plentiful. In summer bats rest and wait during daylight hours in small sheltered areas well above the ground, or in larger dark areas with small access openings, such as attics. In winter the bats will be biding their time in protected areas at ground level and are unlikely to be in or on your house. Bats only need a 3/8 inch opening into a protected area, so numerous entry points are available to bats in the average house. Bat control is recommended, especially if they are roosting in your attic spaces, since the bat droppings, or guano, has been linked to respiratory disease. While rabies from bats is relatively rare, caution around bats is recommended, including wearing protective clothing when cleaning up or investigating their hiding areas.
You have an advantage over many homeowners, in that you have identified their points of entry. These simply need to be sealed. Metal wraps, screening, or caulking are all effective ways of blocking their entrance. Bats don't chew new openings, so the specific material used does not really matter. Given the time of year, we suggest verifying exact entry locations by watching them as they leave in the evening, and then waiting until early November, when you can be sure they have left for the season, to seal the openings. Poisons are not recommended, and ultrasonic devices have not been proven effective. Naphthalene (mothballs) may be helpful in some instances, but exclusion is really the best approach.
Bats are very beneficial for insect control, of course, so if you are so inclined, you might be able to provide them some shelter in a location away from your home. Bat house plans are readily available over the internet or at the library. Bats are quite finicky though and may not be interested in the location or design that you choose, so it may take some patience before they take up the new residence.
I have a persistent moldy odor in the basement. The basement is bone dry, and I have not been able to find a source. Could you offer any advice?
Since you have eliminated the most common source of moldy odors, which is damp conditions and resultant mold growth, we would have to suspect sewer gases. Sewer pipes are a conducive environment for mold and bacteria growth, which could produce the musty odor you're experiencing. Most basements have floor drains, which are often connected to the sewer system, and may be the source. All drains should have traps in them. These are U-shaped bends in the piping that hold water. The water is retained in the trap specifically to prevent sewer gases from entering the house. Since water isn't normally flowing to the floor drain in your basement, the water in the trap has probably dried up. You should add a glass of water to the drain every couple months. Another common source of sewer gas is a missing bypass plug. In order to clean-out the sewer drain, a bypass is built-in to allow the cleaning equipment to get past the trap. The threaded plug may have been removed to allow drainage past a clogged trap, and not replaced. Install a new plug (and unclog the trap, if necessary). Also check to see if you have any infrequently used fixtures in the basement such as sinks, showers or toilets, in which the drains have dried out. Generally, you should be able to see standing water when you look down a drain. On rare occasions, traps have been improperly omitted during the installation of plumbing fixtures. Sewer gas is an obnoxious presence in your home. If adding water to the drains doesn't do the trick, call in a professional for further evaluation and correction.
We had our home inspected and were told that we have termites. The cost to treat for them was astronomical. Can we get rid of them ourselves?
The short answer is no. The chemicals necessary to successfully treat for termites are regulated and not suitable for use by non-certified individuals. Termites live in the ground and migrate into the house to consume the wood. They remain generally well hidden within the wood and no simple treatment of the wood will remove the colony living in the ground. You should get more than one estimate however just to make sure that you are getting a reasonable price.
Prevention is far preferable to treatment. While it may be too late for you, it is a good idea to have the home periodically inspected. A professional inspection will point out any conditions that are conducive to insect infestation. Basically, in regard to termites, any wood close to or in contact with the soil and any damp conditions are invitations to termites, and should be corrected. Especially susceptible are wood framed basement windows, old wood support posts in basements, wood porch posts at grade, wood stored on the soil in crawlspaces, and the wood frames of garage doors. It can cost considerably less to deal with a small infestation than a large one, so poking around in these areas yourself to see if the wood is being eaten from the inside out might be worth attempting. There are some photos of termite damage on our website that you can use to identify any infestation that you might suspect
I am having problems with large amounts of flies in my house, mostly at the windows. What can I do to prevent this?
Many insects, but especially house flies and cluster flies, are interested in getting in out of the cold at this time of year. If the problem is cluster flies, which fold their wings together over their backs when at rest, lawn treatments can help to reduce the problem, and perimeter sprays or other chemical treatments may reduce other insect invasions. Contact a pest control company or your Cooperative Extension office for more information. But an important part of any control program is to better seal the house. Depending on the type of exterior finish, it may be possible to improve the seal from the outside, by caulking all cracks or gaps, particularly between trim and siding, or otherwise filling any holes that allow entry into the walls. In most instances, total success is unlikely from the outside. All interior surfaces should be inspected and better sealed, with caulk or whatever product is compatible with your interior finishes.
Some particular areas to look out for include your windows. They may be in poor condition, with loose or damaged glass, or may just be loose fitting. Often they are simply not fully closed. Check to see if the upper section of a double hung window has a small gap at the top. Exterior doors are also often poorly sealed. Look for daylight around the edges and thresholds, and add weather stripping as needed. Another door to check is your access door to any unfinished attic space. Improving the screens on the vents in your attic may also be helpful. Bathroom ventilators are often a source. You may need to install screening over any ventilator exhaust outlets. Metal grid type suspended ceilings can be a problem too because they do not provide a complete seal, such as drywall or plaster would. Changing to a sealed ceiling finish may be advisable.
Improving the seal around your house can be quite a chore, but looking for and correcting ways that insects can enter your house will also help keep more heat in the house and reduce your heating bills.
I have carpenter ants showing up in my house again, now that it's getting warmer. Can I treat these myself or do I need a pest control company?
Carpenter ants are extremely common in our part of the country, so you have plenty of company if you are seeing them. Carpenter ants are generally larger than other ants, have 90 degree bent antennae and are bulky. They look like ants on steroids. They do not eat wood, but they do chew on wood and other building products to create nest sites and can cause significant damage over time. Carpenter ants are benign outdoors but are a nuisance in the house. Carpenter ant colonies are found in nature primarily in the decaying wood of older trees. The ants that you see in your house may be just foraging, or may have established satellite colonies in the house. They enter our homes because they like the same foods we do, and our homes provide great nest sites. If you see carpenter ants in the winter, you definitely have satellite colonies, because outdoor nests will be dormant due to the cold.
Treating carpenter ants is very easy if you find the colony, but very difficult if you can't find it, and carpenter ants don't make it easy. Typical nest sites include window frames, hollow core doors, entry door thresholds, and any area that is wet, such as around leaking plumbing, leaking roofs, etc. Try tracing their paths back to the colony, and if possible listen for the clicking sounds they make as they chew wood. Topical treatment with an over-the-counter spray will work well on a colony that has been located. If you can't find the nest, call in the professionals. They can apply chemicals that will flush the ants out of hiding for direct application, or apply residual sprays around the perimeter of the house that will keep them in check. Many people opt for annual treatment, but removing older trees from around the house and preventing any leaks may be your best bet.
I have an older home with a crawlspace below part of the house. I recently noticed that some of the floor joists have hundreds of very small round holes and some dry rot. How do I know if this is getting worse, and what should I do to prevent it?
The small round holes are probably caused by powderpost beetles. The wood will look like someone has been throwing darts at it. The “dry rot” is probably damage to the wood caused by the beetles. The larval stage of the beetle bores through and consumes the wood, leaving a cellulose powder behind. A long term infestation can completely destroy the wood. Powderpost beetle damage is common in very old homes. Powderpost beetles can thrive only if the wood has a high moisture content. This would be caused by an overly damp basement or crawlspace. The surest way to prevent or eliminate them is to dry out the space. Better grading and gutters, a vapor barrier on the soil in the crawlspace, and any other measures that will significantly reduce the moisture levels should prevent further activity. What you're seeing may be very old, from a time when moisture conditions might have been worse. In an active infestation you will usually see fresh powder around the emergence holes, which are created as the larvae undergo metamorphosis and become beetles. The beetles then emerge to find a small crack in a new location in which to lay eggs. If you don't see fresh powder around the holes, the infestation may well be inactive. Most infestations were brought into the house with the wood when it was built. Modern kiln drying of wood kills the beetles, greatly reducing the likelihood of a problem in a newer home. You should further evaluate the wood by probing to see if replacement or reinforcement is necessary. The depth of the damage can be used to assess the need for replacement.
I have carpenter bees around the house. They are quite annoying. How can I best get rid of them?
The spring and early summer is the most active time of year for carpenter bees. If they are nesting close to areas where people are also active, they can be quite annoying indeed. The reason they dive bomb people is that the male, who guards the nest, doesn't have a stinger. He puts on a big aggressive show instead. The female can sting, but is not aggressive, and rarely does. Carpenter bees are easily identified. They are large and shaped like bumble bees, but are shinier black with some gold colored hairs. They do not have the small yellow patches that can be seen on bumble bees. They typically nest in untreated or unpainted wood around the house. They especially prefer the undersides of porch rails and fascia boards. You will see the perfectly round half inch diameter entrance holes to their nests which consist of horizontal galleries along the grain in the wood. There is usually a spray of yellow excrement and coarse sawdust on surfaces below the hole. Sometimes you will see oblong and uneven holes on the face of the boards where deterioration has removed the thin remaining wood surface, exposing some of the galleries. Professional treatment usually consists of a powdered insecticide application into the galleries, followed by plugging the holes after a couple of days. Over-the-counter bee and wasp sprays can be effective, however, preventive maintenance is a better approach to control. Make sure all exposed wood surfaces are painted, including the undersides of rails and exposed backs and edges of trim boards, or, even better, wrap all exterior wood in vinyl or aluminum. Carpenter bees can do a fair amount of damage if there are several bees and they are around year after year. So, treat where necessary, but more importantly, make your house less inviting, and you will solve your carpenter bee problem.
I've been hearing scratching noises in one wall of my bedroom lately. I am wondering what I'm hearing and what I should do to stop it.
You are probably hearing one of the many common rodents that can infest houses. These include mice, rats, chipmunks, and squirrels. All of them are extremely destructive and should be controlled aggressively. Significant damage to the structure is unlikely, but damage to wiring and insulation is almost guaranteed. Rodents enlarge existing holes to gain access to new areas. Since our electrical wiring is run through holes in the framing, rodents often chew through the plastic insulation, leaving bare, hazardous wiring. Most thermal insulation provides ideal nesting materials for rodents. Squirrels can destroy an entire attic full of insulation if they manage to gain access. More importantly, rodents are vectors for disease, including hanta virus, and can contaminate our food and clothing.
Based on the habits of various rodents, activity in an attic is almost always an indication of squirrels, activity in lower walls and basements is often chipmunks. Mice and rats can be anywhere, but are normally somewhere in the middle, near a food source.
If you want to deal with the problem yourself, cage type traps are best for squirrels, and snap traps work best for mice. Rats are actually quite cautious and can be difficult to catch. We recommend hiring a professional exterminator if the infestation is extensive or persistent. The best approach however is to find and seal the access points. These can be difficult to locate, but the most common area for mouse and chipmunk entry is between the foundation and framing. Gaps can often be found along the top of the foundation, especially if the siding is close to, or below, the ground. These rodents also often enter at holes in the exterior walls for electric cables or piping. They may enter at poorly sealed garage doors, and then gain access from the attached garage into the rest of the house. The areas of heaviest activity in the house, indicated by nesting and rodent droppings, are usually close to the point of entry. Squirrel entry will most likely occur in the eaves along the edges of the roof. You will probably need to use a ladder to find these locations. In any case, don't ignore the problem, for the sake of your house and your health.
I have been having trouble with small ants in my house. Are they harmful, and can I get rid of them myself, or do I need a professional?
The ants you are seeing could be one of several different types, but are probably pavement ants, also sometimes commonly called sugar ants. They are very small and usually brown in color. They are attracted to sugar and just about any other foods that humans consume. These ants are not harmful to the house, but can become a nuisance. They are the same ants that build those miniature volcanoes at the cracks in your sidewalk. They seem to prefer stone and masonry for their nest sites, and particularly enjoy the sunny sides of homes, most often being found around masonry stoops and walks, and especially on the top of foundation walls, just below the wood sill plate and floor joists. Look in the basement along the top of the foundation wall, or on the basement floor at the base of the wall where the material has fallen, for piles of small granular type material. A close look will probably reveal small dead ant bodies mixed in with the granular material. When you find these piles, you have found the general area of the nest. Any over-the-counter topical ant control product should work well if you have located the nest, but be aware that there may be more than one.
If you can't find the nests, you can attempt control using any of the many bait type ant control products, which attract the ants, who then carry the poison in the bait back to their nest to feed the queen and the colony. The bait should be placed in the area where foraging is occurring. If you are baiting, don't spray the forage site. Give the bait a few days to work. Other inexpensive and more benign treatment products which may be helpful include diatomaceous earth, which can be spread around the perimeter of the house at the foundation to discourage their entry, or boric acid powder, which can be applied in the area of observed activity, especially if you can find the “trail” that they use to get to the location where you see them. If your efforts at control do not succeed, professionals can be called in. They have a larger and more potent array of treatment options that they can use.
As the weather is getting warm I have been dive-bombed by large bumble bees around the house. What can I do to get rid of these pests?
What you are seeing are actually carpenter bees. They look like bumble bees but are generally darker and more glossy in appearance. They buzz around you to scare you away from their nest sites, since they don't generally sting to keep you away. They drill nearly perfect half inch diameter entry holes into the wood around your house to create nesting galleries where they lay their eggs. The best way to discourage them is to make sure there are no unpainted exposed wood surfaces for them to find. They prefer the underside of porch rails, roof eave soffits, the backside of fascia boards, and any other unpainted, sheltered wood surfaces.
Close examination of the area they are protecting should reveal where they are nesting. You may also see yellow excrement stains on the house surfaces below the gallery holes.
Standard treatment consists of a powder pesticide application in the galleries and plugging the holes. But the best environmentally friendly approach may be to wait until their nesting season is over. Then replace the damaged wood and keep the new wood well painted at all exposed surfaces, or better yet, wrap the new wood in aluminum trim material.