When we see termites swarming in and around of the house, most of us harbor a secret hope that all we will have to do is to put out a few cans of smelly stuff and the bugs will flee. Unfortunately, nothing could be further from the truth about termites. If you try using half-hearted do-it-yourself measures to kill termites, you’ll probably find devastating wood damage a month, a year, or maybe two or three years later—most commonly when you are trying to sell your home, when killing termites won’t just cost you what you pay the bug guy, but also what you would make from the sale.
Termite control is costly, and it’s a lot of work. But getting rid of termites for good is definitely something you can do on your own if you have the essential information, starting with these fifty essential facts about termites every homeowner needs to know.
Table of Contents
32. Bamboo borers
33. Carpenter ants
34. Carpenter bees
39. New house borers
40. Old house borers
42. Wood beetles
There are at least 4,000 species of termites in the world, but only 400 to 500 of them cause damage to wooden structures in buildings, forests, or crops. There are about 50 species of termites in the United States and Canada, but only four cause significant problems in buildings. There are just four types of termites that are especially abundant in North America are:
• Dampwood termites (Zootermopsis angusticolis)
• Drywood termites (Incistermes minor)
• Formosan termites (Coptotermes formosanus)
• Western subterranean termites (Reticulitermes hesperus)
We’ll review each type of termite in more detail later.
The very first step in identifying a termite, if you never have seen one before, is distinguishing whether or not it’s an insect. Like all other true insects, termites have three pairs of jointed legs, one pair of jointed antennae, and two pairs of wings. Termites belong to the order of insects known as Isoptera, or “equal wings.” Every termite has two pairs of wings of equal length, and almost all termites can fly at some time in their lifespan.
But how does knowing that help you tell whether or not an insect is actually a termite? Here are some helpful details:
• Both termites and ants have segmented antennae, but ant antennae are segmented, with joints, while termite antennae look like beads in a necklace. Ant antennae bend at joints, while termite antennae stick out straight from the head. To tell the difference quickly, of course, you’ll need a magnifying glass. The first segment of an ant’s antenna is long, and the outer segments are shorter, attached to the first segment by an elbow, and held at 30º-90º angles to the segments behind them. Both termites and ants use their antennae for smell, taste, and, despite the fact they may have compound eyes, sight.
• Termite eyes do not give the insect sharp vision, but they are excellent for detecting changes in light. Termite swarms are always attracted to light. As a result, the place you find mounds of termites is not necessarily the place where they have their colony. They may have simply migrated from one side of the room to the other, seeking a window admitting bright light.
• Ants sting, but termites bite. An ant defends itself with the stinger on its tail, but a termite has biting and chewing mouth parts that it moves from side to side. The termite’s mandibles, or jaws, are capable of grinding wood into the consistency of peanut butter, and it has another set of “grinders” known as the proventriculus in its digestive tract. African native healers have been documented using the termite as a kind of injection device, spreading a medicinal substance on the patient’s skin, and then placing termites on the skin to bite and inject the medicine.
• All four of a termite’s wings are the same length. An ant has two longer wings of the same length, and two shorter wings of the same length.
• Only mature kings and queens in termite colonies ever develop wings, and their wings break off after the colony has completed its flight. If you see a tiny pile of wings all of the same length, this can mean a termite colony has moved into your home.
• Termites have “hooks” on their feet that allow them to climb and to navigate rotting wood.
• Termites have bigger tummies than other insects. A termite’s abdomen is broadly joined at its waist, while bees, wasps, butterflies, and ants have tight waists.
• A termite breathes through its abdomen. The abdomen has 10 segments. Eight of these segments on the abdomen have tiny breathing tubes known as spiracles.
A tiny termite emerges from the egg as a nymph. Even at this stage, it looks like an adult termite, only much smaller. Unlike an insect that goes through the larva stage, a termite has a protective outer skeleton, or exoskeleton, the moment it emerges from its egg.
Because the skeleton of the termite is rigid, it has to molt every time it grows. Termites go through six moltings, or instar stages, as they mature from nymph to adult. Other termites in the colony cannibalize the molted exoskeletons, which are a rich source of protein.
Termites swarm only when the reproducing kings and queens recognize that the combination of humidity, temperature, and light are just right.
The humidity must be high, so the colony can start digging in soft mud, rather than hard wood. Termites are most likely to swarm after a rain. However, homeowners can unwittingly mimic the benefits of a recent rain by spreading gallons of liquid termite poisons under the house. The termites are attracted to the moisture, and if their timing is right, they may arrive while the ground is still damp but the poison has broken down.
Seeing a swarm of new termites after putting out pesticide is an extremely frustrating experience for homeowners—especially if they have paid an exterminator hundreds or thousands for the treatment. Swarming of termites can also be triggered by lawn sprinklers and by washing down patios and garage floors with a hose. The trickle of water flowing down through expansion joints can activate an undetected underground colony to swarm.
Termites also prefer to swarm at warm temperatures. Typically, a colony will swarm on a warm, sunny spring or summer day when the temperature is around 68ºF/20ºC. Termites prefer to swarm on a clear day with good sunlight, but turning on a bright light in a house on sunny day just after a rainstorm may also attract a swarm.
When conditions are just right, termites will swarm, the direction of the flight dictated by light. Indoor termites tend to head for windows. If the window is open, they often will get caught int the screen.
Termites may also swarm from place to place within a house, condominium, office, or apartment. If there is no exposed wood, the colony will quickly die of starvation. Any kind of exposed bare wood, however, can provide a temporary home for termites. This can be the wooden arms and legs of chairs and tables, wooden picture frames, or even wooden serving bowls and planters.
Termites seldom swarm successfully outdoors. They are poor fliers, and they will set down after traveling a distance you could walk in 4 or 5 steps. Most termites are quickly consumed by birds and reptiles, very few finding a warm, muddy building site for a new colony. For this reason, termite infestations usually have to be brought in by humans not paying attention to the condition of lumber and furniture before bringing it into the home.
Termites go through a kind of courtship before pairing for life. The king finds an inactive queen to which he is attracted, and follows her around for about a week until she finds a suitable home for a new nest. They then mate. The queen may live up to 25 years and lay up to 60,000 eggs. The eggs of most termite species take 55 to 60 days to hatch, although dry wood termites take up to 77 to 80 days to hatch.
It’s the king and queen termites that you are likely to see swarming. In most species, the first batch of eggs hatches into worker termites, the thin-skinned, creamy-white, maggot-like insects you may see when you break open a piece of termite-infested wood. Later hatchlings may mature into soldier termites, which are blind and easy identified by their brown, hard heads and two large jaws (used to defend against predators), or into another queen and king, which also have coloration similar to ants.
In dry wood termites, all nymphs do the work of building tunnels and feeding the king and queen for the first year of their lives, and then become soldiers as they mature.
In humans, certain species of bacteria such as Lactobacillus assist with the process of digestion. In termites, certain species of one-celled animals known as Protozoans break down the cellulose in wood that the termite cannot digest for itself. The Protozoans convert the cellulose to starches the termites can use for food. Introducing microorganisms that compete with the Protozoans can kill termites by depriving them of the means to digest their food.
Tiny termite nymphs don’t have jaws strong enough to chew wood, and their reproductive tracts have to be inoculated with the Protozoans that digest cellulose once they do. That is why the king and queen have to feed the first batch of nymphs, and later nymphs are fed by other adults in the colony.
Exactly how termites feed each other is a little gross, but here it is: Older termites vomit pre-digested somotodeal food droplets into the mouths of nymphs. The nymphs acquire the Protozoans they will need to digest their own food by proctodeal feeding, licking liquid droplets from the anus of an older termite. The nymph is not capable of digesting its own food until after its third molting.
Most species of termites that cause problems in construction feed on spring wood, the softer layers of sapwood, and avoid summer wood, the harder growth rings. If you see that termites have followed the grain of wood as they ate it, you will know you don’t have drywood termites. However, if you see wood that is hollowed out by termites, which eat both spring and summer growth, then you can know that you have drywood termites.
Old-growth redwood is resistant to termites, but this kind of wood is very rare today. Species of trees that produce essential oils, such as cedar, produce wood that is less vulnerable to attack, until the essential oils in the wood dry out.
Some species of termites produce a special kind of queen known as a supplementary reproductive. This is an “assistant queens” that does most of the egg-laying after the colony has about 10,000 members. With supplementary reproductive queens, termite colonies can grow very large:
• A drywood termite colony may consist of 2,000 to 3,000 members.
• A dampwood termite colony may consist of 3,500 to 4,500 members.
• A subterranean, mud-dwelling termite colony may consist of tens of thousands of members.
• A Formosan termite colony may consist of as many as 6.8 million members.
Subterranean termites are found in every state of the United States except Alaska and through most of Canada except in the Yukon, Northwest Territories, and Nunavut. These termites play a vital role in the environment, helping to break down fallen trees, turning them into fertilizer for new growth. Unfortunately, just as underground termites recycle dead trees, they can also emerge from the ground into the wooden framework of homes and office buildings, undetected until it is too late.
Subterranean termites multiply into huge numbers because their kings typically have concubines, the supplementary reproductives or assistant queens. If the queen is injured or dies, any supplementary reproductive can take her place. Subterranean termite colonies tend to “bud,” or form nearby separate colonies, as they consume the wood in a house or building.
These termites also eat paper, burlap bags, cotton, rattan, twine, and other plant products. They are attracted to the odors of decaying wood, which is easier for them to chew, and sometimes the termites also consume the fungi that cause decay. Subterranean termites must maintain contact with the soil as their moisture source, or they need an above-ground source of moisture, such as a leak in the roof, a leak in plumbing, condensation around an air conditioning vent, or a leaking rain gutter.
Subterranean termites have to have a dependable moisture source. If you live in an arid or desert climate, you can still have a problem with subterranean termites, but if you do, you almost certainly have some kind of leak in your plumbing supply. Subterranean termites can also be detected by these signs:
• The first sign of infestation, in most homes, is swarming. The king and queen drop their wings at their new colony site. There may be termite wings on a windowsill, in a window screen, or stuck in a cobweb. Signs of swarming on the outside of a window is a sign that termites are attacking buildings nearby.
• Subterranean termites live in mud. They may create mud shelter tubes around utility connections, around piers in crawl spaces, and along foundation walls and slabs.
• The first wood damaged by subterranean termites is usually the wood that is in direct contact with the ground. There may be no visible damage on the outside of the wood, but tunnels and galleries may be detected by sounding the wood, tapping on it with a screwdriver handle or similar tool. When the tapping sound is dull or hollow, open the wood with a sharp instrument, to look for damage. Subterranean termite tunnels tend to follow the grain of the wood, and they tend to be lined with pale, spotted, soft fecal material applied to the walls of tunnel as a kind of plaster. The wood may also be rotted by fungi.
See my article with step-by-step instructions for getting rid of subterranean termites.
Repellent products do not kill termites. They just turn them away. Repellent products such as Dragnet (permethrin), Suspend SC (deltamethrin) and Talstar (bifrenthrin) provide immediate protection against termites and last for up to 5 years, but if even a tiny gap around the structure is missed, termites can go right in. Termites are not killed by these products, so they can still swarm and infest nearby structures.
Non-repellent chemicals for termites are poisons the termites can’t taste, smell, or see. They also start working immediately, and are usually effective for about 5 years. If a spot is missed, however, the product still can kill the entire colony. Non-repellent termiticides in use in the USA today include Phantom (chlorfenapyr), Premise (imidacloprid), and Termidor (fipronil).
Both repellent and non-repellent products for controlling subterranean termites are applied to the soil as drenches. If the product is not mixed properly, as mentioned above, and the toxin or repellent is not at the right strength, it can actually attract swarming termites.
Termite baits are an alternative to liquid treatments applied directly to the oil. Baits contain an insecticide that worker termites take back to the colony and share with other members of the colony. These products do not keep termites from entering a structure, but they are intended to reduce the numbers of termites in a colony so that they no longer to substantial damage to the structure.
The advantages of termite baits include:
• Smaller amounts of insecticide are used, compared to liquid treatments.
• No need to drill into patios, walkways, and slabs.
• No need to leave the home during treatment.
The disadvantages of termite baits include:
• Termites may not find the baits right away, so the colony may not be affected for several months to a year.
• Termites are unaffected if they do not bring the bait to the colony.
• The poisons in the baits break down quickly, so they have to be reapplied every 1 to 3 months.
• As soon as the baiting program is stopped, damage may resume.
• Not all termite baits actually work.
The Formosan termite is similar to subterranean termites in that it lives underground and feeds on cellulose, but it attacks a greater variety of woods and typically creates colonies of more than 1 million members (400 times as many termites as in a colony of drywood termites). They feed not just on lumber but also on living trees, including citrus, pecans, willows, wax myrtle, white oak, sweet gum, cherry laurel, willow, and Chinese elm, and they eat both early and late season wood, not just the softer early season wood.
A swarming Formosan termite is yellowish brown and usually a little more than ½ inch (12 mm) long. It is easy to distinguish from other kinds of swarming subterranean termites that are usually dark brown to almost black and about ¼ inch (6 mm) long. The wings of Formosan termites are covered with dense hair. Formosan termite soldiers are aggressive, sometimes attaching themselves to a finger, and they can release a white defensive substance from the fontanel at the base of its head. Formosan termite workers, however, are very hard to distinguish from other species.
The tunnels formed by Formosan termites are usually free of the black and brown specks of feces left by other species. They use their feces, however, to build a structure known as a carton, which they may construct either in the ground or in a wall. Formosan termites chew through non-food materials such as plaster, plastic, rubber, and asphalt to get to the wood they eat.
Formosan termites are fond of landscape timbers, especially the recycled railroad ties so popular with home gardeners in Texas and the Southeastern United States. This kind of termite is undeterred by a creosote treatment on the wood, so even if the wood has been treated to make it water-proof, it isn’t termite proof. The termite colonies swarm from the landscaping timbers to trees in the yard and wood in the house and outbuildings, usually about a year after the landscaping timbers are brought to the premises.
Formosan termites are also transported from place to place inside wooden pallets. It can be a lot harder for the colony to make the jump from the pallet to a permanent home if the pallet is stored in a metal building with a concrete floor, but homeowners who use pallets in informal building projects sometimes put their entire property at risk.
The fecal cartons Formosan termites build in walls and crawl spaces contain enough moisture to sustain the colony. Each nest may be as large as several cubic feet (20 to 50 liters). It is essential to remove these nests to get rid of termites. They can be located with a moisture meter.
Termite expert Terry Singleton says that termite inspection reports find that 46.8% of all homes in California contain evidence of drywood termites. Although drywood termites are particularly well adapted to the climatic conditions of California, they are also common on the Gulf Coast and southeastern Atlantic coast of the United States. Drywood termites are quite rare in Canada.
The first sign of an infestation with drywood termites usually is the emergence of a swarm from small holes they have eaten through the surface of wood. The presence of a swarm of these termites is a sure sign that interior wood has been damaged.
Living inside wood, drywood termites produce tiny fecal pellets. The pellets are only about 1/32 of an inch (less than 1 mm) long, and they are usually the same color as the wood on which the termites have been feeding. If you look at the pellets through a magnifying glass, you will detect long flutes or dimples down each surface. The pellets are pointed at one end and blunt at the other
The magnitude of damage may not be apparent until an entire timber fails usually years after infestation. Drywood termites can be distinguished from subterranean termites by the fact that they eat both the harder, summerwood and the soft spring wood, eating through the “rings” of the tree, and they can be distinguished by Formosan termites by leaving piles of feces outside the wood they infest. Formosan termites use their feces to make their nests.
Unlike subterranean termites that commute from their underground homes to feed on timbers, drywood termites live inside the wood they eat. In sound wood, drywood termites do not have access to free water, and have to get their water from the wood itself; that is how they got their name.
Unlike other species of termites, drywood termites remove their feces from their tunnels. Drywood termites make small holes in the wood they infest to remove fecal pellets and frass (wood dust). Piles of pellets accumulate under these openings, making it easier to identify the termite. Drywood termite pellets are usually about1/25 of an inch (1 mm) long. If you look at them through a magnifying lens, you will see 6 concave sides and two rounded ends. They are usually the same color as the wood on which the termites are feeding. It’s impossible to determine whether pellets are old or fresh, although black or purple pellets around lighter wood may indicate a very old infestation, as much as 20 years or more.
The one sure way to prevent drywood termite infestations is to build your home without wood—and increasing numbers of homeowners in areas where drywood termites are a common problem are doing just that. If your home is already built of wood, however, there are many things you can do to keep termites under control:
• Seal or paint all exposed wood to prevent termite entry.
• Use heat-treated wood for outdoor applications.
• Dust wood with boron compounds, used following instructions. Borax treatment won’t work if it isn’t applied in the right concentration. Seasoned, dry wood cannot be treated with borax or borates to remove existing infestations, but borax powder can be spread in attics and crawl spaces to prevent infestations by new swarms of termites.
Other methods, such as heat treatment, liquid nitrogen treatment, dry poisons, borax dust, liquid poisons, termite baits, and microwave treatment typically leave a few survivors that can tend eggs and restart the colony.
Also known as rotten-wood termites, dampwood termites don’t require any moisture from the ground, as long as they are able to infest especially damp wood (such as is found in the Pacific Northwest of the United States and in coastal British Columbia). The adult dampwood termite grows a full inch (25 mm) long, and has a brown body and brown wings. The soldiers of this species are only about half as large. The fecal pellets of dampwood termites have 6 sides that are flattened, rather than concave (pushed inward), and they are about 1/25 to 1/20 of an inch (1 to 1.5 mm) long.
Dampwood termites usually eat across the grain of wood. There is no dirt in their tunnels. This species of termite is most commonly encountered in the wild, and only rarely causes problems in human habitations.
The powderpost termite is named after its ability to turn wood into powder. A relatively small termite that grows to just 7/16 to ½ inch (10-12 mm) in total length, its transparent wings are typically longer than the rest of its body. Its body is pale reddish brown to pale yellowish brown, with metallic blue and green reflections.
Powderpost termites live in drywood, obtaining their moisture from the wood they eat. They typically live in limited areas of a structure, such as window trim, fascia, doors, and furniture. Sometimes they build shelter tubes of dried feces to connect adjacent pieces of wood. Their activity in furniture may appear to have formed blisters in the wood where their tunnels are close to the surface.
Termites aren’t the only insects that infest wood.
Species of ants, bees, and beetles are known to infest wood. Sometimes there is no reason to attempt to kill them, since once they have emerged from wood they cannot reinfest it. Here are the insects you need to know.
Bamboo borers are a tiny, brown, cylindrical beetle, growing to about 1/8th inch (3 mm) length in maturity. The females lays is eggs both on surfaces and in crevices. As its name suggests, it feeds on bamboo furniture, and also stored grain, flour, and some drugs. It will continue to infest its food source until the entire interior has been reduced to a fine powder.
Carpenter ants are found all over North America, except in the Arctic. They usually cause only minor problems, if at all. A carpenter ant can be distinguished from a termite by its jointed legs and antenna, and its relatively narrow, tight waist. There are 25 species of carpenter ants in the United States, out of about 1,000 worldwide. The species of carpenter ant American homeowners are most likely to encounter, Campanotus pennsylvanicus, prefers the more humid climates of the United States east of the Rocky Mountains to the Atlantic seaboard. Its exoskeleton is dull black all over, although its wings and antennae may be vested with yellow hairs. The worker ants of this species grow to between ¼ inch (6 mm) and ½ inch (12 mm) long. Carpenter ants are attracted by moisture, and usually enter the residential structure on tree limbs.
Carpenter bees prefer to nest in softwood, such as cedar, cypress, pine, and redwood. The adult bee is ¾ to 1 inch (18 to 25 mm) in length, and resembles a honeybee except for the top of the abdomen, which is devoid of hair and usually dull black. The wings of the carpenter bee may be a dark, metallic blue with purple or green reflections, and the entire body of the bee is covered with bright yellow or orange hairs. Carpenter bees are easily identified by the large (approximately 1 inch/25 mm) openings they gnaw into the wood, their hives always built at right angles to the “door” they chew into the wood. The activities of the carpenter bee hive cause minimal damage to wood, although their buzzing can be a constant annoyance. The queen been only raises 6 to 9 hatchlings; the abandoned nest may become a home for cockroaches, ants, or other bees.\
False powderpost beetles infest freshly cut hardwood, especially firewood, wreaths, and rustic furniture made with lumber that has not yet been seasoned. The powderpost beetle is named for its ability to turn posts into powder; a “true’ powderpost beetle makes a finer powder, but beetles of this species are not commonly a problem in the United States and Europe. The adult false powderpost beetle has an elongated, cylindrical body, almost always with a downward pointing head that is covered by its thorax, anywhere from 1/8 inch (3 mm) to 1 inch (25 mm) long. The antenna extend out straight from the head with a “club” at the end. The larvae of this beetle are cream-colored, wrinkly, and C-shaped. False powderpost beetles dig tunnels they fill with frass, a fine powder of wood, and damage the wood with tiny exit holes of 1/10 to ¼ inch (2 to 6 mm) in diameter.
Flat-headed borers are squat, elongated, reddish-brown beetles with an exoskeleton that has a metallic glint. The larva may take several years to mature, but the adult only lives 3 to 5 months. They attack trees, rustic furniture, fences, and log cabins. As the adults emerge, they make oval escape holes about 3/8 inch (8-9 mm) in diameter, closely packed together.
Furniture beetles look like miniature, gray cockroaches. They grow from ¼ to 3/8 inch (6 to 8 mm) long, and their heads, when viewed from above, appear to be hooded. The two antennae have 11 segments. The larvae of this insect are actually large than the adult, and scarier in their appearance. Larvae have a row of spines on their back and two large black “jaws” they use to chew wood. Exit holes of these beetles are typically about 1/8 inch (3 mm) in diameter. The wood may be marked with other, smaller holes drilled by parasitic wasps that feed on the larvae.
Lead cable borers are black, brown, or reddish-brown beetles that grow about ¼ inch (6 mm) long. Their heads are tucked underneath their bodies and cannot be seen from above. This insect gets its name by its ability to drill through protective lead sheathing places around phone and power lines. It feeds on telephone poles, maple, and other hardwoods.
New house borers only lay their eggs in bark, and only found in newly milled lumber, about a year after it leaves the sawmill. They prefer green lumber, especially Douglas fir. They can bore through composite shingles, linoleum, plaster, and roofing to emerge. Lumber that has been air-dried for at least one year or kiln-dried will not be infested. Once these beetles leave wood, they cannot return, since they cannot eat seasoned wood.
Old house borers are common in the Eastern United States, where they do almost as much damage to residential construction as termites. These bugs only eat softwoods such as pine and spruce; they do not feed on hardwood. The adult old house borer may be recognized by its hairy head and thorax, its body growing from 6/10 to 1 inch (15 to 25 mm) long. These beetles may reduce timbers to a thin veneer of wood surrounding a core of dusty frass. They are especially destructive to floor boards and rafters.
True powderpost beetles are reddish-brown, flat, cylindrical insects that only reach a length of ¼ to 1/3 inch (6 to 8 mm) in maturity. They preferred newly cut or partially seasoned oak, ash, and hickory, although they will also attack cherry, walnut, bamboo, and plywood. They can only feed on wood with a moisture content between 6 and 30%, but they are usually able to attack wood in homes with central heat and air conditioning. Their exit holes riddle wood with holes 0.03 to 0.13 inches (0.8 to 3.2 mm) in diameter, the holes formed when adult beetles exit the wood to look for a new food source. Once these beetles have left a food source, they seldom come back to reinfest it.
Just about the only insecticide that kills wood beetles cost-effectively is methyl bromide. Methyl bromide is strictly regulated, however, and even licensed pest control professionals usually are not permitted to use it. It is usually necessary to transport furniture to a fumigation vault, such as those used by furniture importers, for piece by piece treatment. Even when this is possible, it’s important to take into consideration that leather, rubber, and latex exposed to methyl bromide often forms hydrogen sulfide, developing a rotten egg smell.
Sulfuryl fluoride can be used for home fumigation of wood beetles, but it has to be applied in 10 to 20 times the amount normally used for treating termites. Reducing the am0unt of gas used to fumigate the home is a wasted effort, and you probably won’t be able to buy the product without a license.
So what can homeowners do on their own about wood beetles? It turns out there is quite a lot, as you can read in my article on Step-by-Step Treatments for Wood Beetles.
One out of every 10 trees used for lumber in North America is felled to replace wood damaged by fungi that cause the condition dryrot. Some kinds of wood, especially Douglas fir, Monterrey pine, and white pine, are extremely susceptible to fungi. Other kinds of wood, such as bald cypress, juniper, Pacific yew, and Western red cedar, are relatively resistant to dryrot. No kind of wood, however, is completely resistant to fungal attack.
Sometimes fungal infection of wood pops out in a recognizable Poria mushroom, similar to the tuckahoe mushroom you might find in the supermarket.
The mushroom attacking the timber inside a warm, damp area of the frame of your house may send out a root-like rhizomorph as much as 30 feet (9-10 meters) from the site of the damage to the outside of your home to provide the fungus with a dependable water supply. Even if the inside of your house looks nice and dry, if fungi are connected to outdoor water supplies through the rhizomorph, they will continue to flourish. Poria mushroom are a problem on Douglas fir construction in northern California, coastal Oregon, coast Washington state, and coastal British Columbia.
Wood decay caused by fungi is known as dryrot, in two forms known as brown rot and white rot.
In brown rot, the infected wood is brown, shrinking and breaking up into irregular chunks both along and across the grain of the wood. Brown rot can cause loss of structural integrity even before the rot is visible. Damage can be rapid.
In white rot, the damaged wood has a bleached out appearance. The wood may peel off in strings. Loss of structural integrity may appear very quickly.
There are two steps to repairing dry rot. One is to locate and eliminate the source of moisture, and the other is to carve out the area of damage, treat it with a registered fungicide, and repair it with a wood filler. Never put a new piece of wood to “brace” wood damaged by dryrot since the fungal infection can quickly spread. See my article on Step-by-Step Instructions for Dry Rot Repair.
Molds are superficial fungi, usually black, green, or yellow-green. They do not cause structural damage and they can be easily scraped off. However, the presence of mold indicates that conditions are ideal for the growth of wood-destroying fungi.
Blue-stain and sap-stain fungi penetrate deeper than molds but likewise do not damage it. However, the wood will become unsightly. It cannot be scraped clean because the mold grows deep into the wood.
It seems really easy just to spray borate foam on rafters and floor members to prevent termite infestations, and it really is. The problem is that unless you drill into wood and inject borate foams into termite colonies under high pressure, it will have no effect on insects that are already living in the wood.
Cooling wood to -25°C/-15°F will kill termites on contact, but just because you are pouring liquid nitrogen around, you won’t necessarily kill all termites. Concrete foundations, for example, both retain heat and act as insulators. If you are trying to get rid of termites in timbers attached to a concrete slab, you may have relatively little luck with liquid nitrogen.
Electric shock kills termites within 30-60 cm/1-2 feet of the application site, but it’s necessary to use the termite zapper over and over again along the entire length of lumber to get good results.
In fumigation, the entire house is covered with tarps, windows and doors are closed tightly, and a toxic gas is released. It takes 16 to 20 hours to kill termites, and another 12 hours to air out the house. All people and pets have to be excluded from the house. Food and medications that aren’t in factory-sealed glass or metal containers (plastic food containers and pill bottles won’t protect against the gas) have to be taken out of the house; anything you forget to take with you has to be thrown out. And although fumigation gets rid of all existing termites, it offers no residual protection against future swarms.