7B Management of Wood Destroying Organisms: Unit 2. Pest Identification and Biology - Test Your Knowledge

Ants and termites are both social insects. What are three differences between termite and ant colonies?

1. Ants go through complete metamorphosis; termites go through incomplete (gradual) metamorphosis. 2. Ant colonies can have either a single queen or multiple queens, depending on the species. Termite colonies have a single king and queen (although secondary reproductives can also produce offspring). 3. Ant colonies consist almost exclusively of females. Ants produce males only once a year, in time for mating flights. Termite colonies, in contrast, contain both male and female members at all times.

What is swarming? When does it usually occur?

A method of dispersal that termites and ants use to establish new colonies. Subterranean swarmers (alates) emerge from the colonies at certain times of the year when conditions are right. Peak swarming season for subterranean termites in Virginia is from March through May or June. One species swarms in late summer as well.

What is Poria rot? Why is it considered a problem?

A type of fungus that is especially damaging to new or remodeled houses. Poria is a serious pest of coniferous softwoods, which make up most of modern framing and construction materials.

Which powderpost beetle prefers wood with a high moisture content?

Anobiid beetle. Its larvae prefer the sapwood of softwoods with a moisture content of 13% to 30%. This is why anobiids often live in basements and other places with relatively high humidity and warm temperatures.

Termites belong to an insect order called Isoptera ("equal wings"). Why?

Because the front and hind wings of the termite swarmers are the same size and shape. This is different from most other insects (like ants) where the front wings are typically larger and different in shape from the hind wings.

While inspecting a client's home, you see round exit holes about 1/4 inch in diameter. You also find clumps of powdery frass containing wood fragments. What insects are likely to blame?

Bostrichid beetles.

Name the two types of fungi that usually cause wood to decay.

Brown rot and white rot.

You are in a crawlspace examining a floor joist that is dark brown and cracked in a checkerboard-like pattern. What has likely caused this damage?

Brown rot fungi.

How do mildews, molds, and stain fungi affect wood?

By causing cosmetic damage, thus making the wood look bad. Typically, mildews, molds, and stain fungi discolor the wood by turning it pink, gray, green, orange, blue, or black. However, the color only comes from the colored spores on the surface of the wood and rubs off easily with a gloved hand. Molds and mildews feed only on the surface cells of the wood and do not reduce the wood's structural integrity. Nonetheless, mildews do make the surface of the wood more porous so that it holds more moisture. Increasing the moisture content makes the wood more vulnerable to wood decay fungi and insects.

How do carpenter ants damage wood?

Carpenter ants do not eat wood. Instead, they damage wood by excavating it (chewing it up and spitting it out) to build their nest. Typically, carpenter ants infest wood already damaged by moisture or termites. When they infest damaged wood, carpenter ants are merely a nuisance. As their colony grows, however, they begin to chew further into the undamaged wood. This increases the size of the damaged area.

Your client finds piles of coarse sawdust containing ant body parts under a wooden cabinet. What insects are likely to blame?

Carpenter ants.

Why are carpenter bees considered structural pests?

Carpenter bees bore into seasoned woods - especially softwoods such as cedar, redwood, pine, and fir - to build their brood chamber. These bees may damage soft or weathered wood on porches, decks, sheds, railings, overhead trim, porch furniture, fence posts, wooden shingles, wood siding, windowsills, and wood doors. The damage caused by one or two bees is slight. However, carpenter bees are territorial and prefer to create their chambers in the same wood from which they emerged. Carpenter bees that reinfest the same wood year after year can cause significant wood damage.

How can you tell carpenter ant damage from termite or wood-boring beetle damage?

Damage from carpenter ants is distinct from that of termites and wood-boring beetles. Ant galleries do not follow the grain, and ants keep their galleries smooth and clean. You will not find mud, powdery dust, or six-sided pellets in ant galleries as you would with subterranean termites, wood-boring beetles, or drywood termites.

In Virginia, how do subterranean termite colonies begin?

During the daylight hours in the spring, large numbers of termite swarmers (new kings and queens) will emerge from their parent colonies to begin their mating flight. After their flight, termite swarmers fall to the ground and their wings break off. Males and females pair up and begin a new nest, looking for a spot of soft soil. After finding a suitable spot, the new kings and queens seal themselves inside the nest to mate. The mated queen will then produce her first batch of eggs. These eggs will become the first workers. The king and queen will continue to produce eggs while the workers, ever increasing in number, start to forage and take care of the nest.

What do Formosan termites look like?

The soldier and swarmer castes are used to identify species of subterranean termites. The Formosan soldier has a distinctive oval-shaped head, like a teardrop. This shape is quite different from the oblong, rectangular head of native subterranean soldiers. There is a small pore on the front of the soldier's head. If the termite is attacked, this pore secretes a white, gluelike fluid. Formosan swarmers are almost twice the size of native termite swarmers. Instead of being dark colored, the Formosan swarmers are yellow. In addition, Formosan swarmers have very hairy wings. The wings of the native Reticulitermes spp. are hairless.

What are the most distinctive signs of an old house borer infestation?

The sounds of larval chewing at night, wavy ripples on the surface of the wood galleries, large oval exit holes, and galleries tightly packed with frass.

Which type of termite is the most economically important pest in the United States? Why?

The subterranean termite. It causes millions of dollars worth of damage to buildings, books, documents, and photographs each year.

If foraging worker termites find a good source of food, how do they attract other workers to the food site?

They lay down an odor trail from the nest to the food site. They do this by secreting pheromones (odor chemicals) from glands on their abdomen. The intensity of the pheromone trail depends on the size and quality of the food source as well as soil moisture, temperature, and compaction.

Name some places where termites can enter structures.

Through cracks in the concrete slab, utility conduits, expansion joints, and plumbing connections.

What is the main reason to use scientific names to identify pests?

To avoid confusion. Common names vary widely, and these names are not consistent from place to place. Scientific (Latin) names are the same throughout the world.

What is the MAIN reason that subterranean termites build mud tubes?

To keep from drying out (desiccating). Soil furnishes moisture, essential for termite survival. Mud tubes allow termites to travel away from the soil and still maintain their necessary body moisture.

What is the main function of primary and secondary reproductives?

To produce eggs and contribute to the growth of the colony.

What characteristics distinguish anobiid beetles from lyctids and bostrichids?

Unlike the other powderpost beetles, anobiids have digestive yeast in their gut that allows them to digest cellulose. The frass produced by the larvae contains fecal pellets shaped like a hotdog bun.

What basic requirements do fungi need in order to survive?

Favorable temperatures, enough moisture, adequate oxygen, and food.

A hardwood board looks bleached out and becomes soft and stringy. What is the likely cause of the decay?

White rot fungi.

What type of wood is often infested by lyctid beetles?

Hardwood items less than 10 years old. Older wood has a lower starch content and does not have enough nutritional value for the developing larvae.

What are wood decay fungi? How can they damage wood?

Wood rots. These fungi penetrate the interior of the wood by secreting chemicals (enzymes) that break down the components of the wood into simple sugar compounds. The fungi produce reproductive structures called fruiting bodies. The fruiting bodies produce spores, which behave like microscopic seeds. If they land on a wood surface with enough moisture, the spores begin to grow. The new fungi will break down the wood as it feeds and grows. Wood decay fungi can cause serious structural damage if left untreated.

How do subterranean termites locate sources of food?

No one knows exactly. Termites seem to forage by digging a network of tunnels out from the nest, locating food resources by chance in the process. However, there is still much that is unknown about termite foraging behavior.

Your client has found two carpenter ants on a bedroom windowsill at 2:00 p.m. Is the ant colony nesting within his house?

Not necessarily. More than likely, the ant colony is nesting outside, and individual workers are entering the home to look for food or moisture. Your client should watch his windowsill at night. If he sees hundreds of ants on his windowsill after 10:00 p.m., he may have a colony living in the house.

You discover oval-shaped tunnels packed with powdery frass. The galleries have a wavy pattern on the surface of the wood. What insects are likely to blame?

Old house borers.

How can you tell a soldier termite from a worker?

Soldier heads are enlarged, hard, and yellowish brown. At the front of the head are two enlarged mandibles (jaws). Worker heads are small, round, and white. Worker termites do not have enlarged mandibles.

What are Formosan termites? Why are they important?

Subterranean termites that were accidentally imported into the United States from Asia after World War II. Formosan termites are more vigorous and aggressive than Reticulitermes spp. Their populations also grow more rapidly, and they eat more wood than native termites do. Formosan termites also attack living trees, which is very uncommon among native subterranean termites. For these reasons, we need to be on the lookout for Formosan termites in Virginia. Formosan termites are not currently established in Virginia. However, they have traveled into several southern states on trucks carrying railroad ties used for railroads or landscaping timbers. Formosan termites are currently established in North Carolina. They should be able to survive in Virginia within heated structures.

Your client has noticed mud tubes over the foundation of her house as well as dead swarmers in her windowsills. What insects are likely to blame?

Subterranean termites.

How are termites able to digest cellulose from wood?

Termites have microorganisms (protozoa and bacteria) in their gut. These microorganisms digest the cellulose, converting it into sugars and nutrients that termites can use.

Name three distinguishing characteristics of drywood termites.

1. Drywood termites need no contact with the soil. 2. Drywood termite galleries cut across (not along) the grain of wood. 3. Drywood termites produce cylindrical fecal pellets that are the same color as the infested wood and have six distinct depressions on the sides.

Subterranean termites produce four kinds of aboveground mud tubes. Name and describe them.

1. Exploratory tubes - tubes that protect against desiccation and predators such as ants while foraging above ground. 2. Utility tubes -more permanent mud tubes used to connect underground termite galleries directly to the food source. 3. Suspended or drop tubes - lighter color tubes (containing more wood fibers) that drop from the structural wood sometimes reaching down to the ground. 4. Swarming tubes - tubes that are built seasonally and function as an exit port for swarmers leaving the colony.

What functions do worker termites perform?

1. Foraging for food. 2. Building tunnels in the soil and galleries in wood. 3. Caring for the young. 4. Grooming and feeding the other colony members and each other. 5. Repairing the nest.

Why is it important to understand the life (developmental) stages of insect pests?

1. It will help you identify insect pests, which may change radically in appearance from one life stage to the next. 2. The presence of one stage (ex. an adult wood-boring beetle) can alert you to the presence of a more destructive life stage (the larva) causing damage in the wood. 3. It will help you decide which stage is most vulnerable to control.

How can you distinguish winged termites from winged ants?

1. Termites have straight antennae; ants have elbowed antennae. 2. Termites have thick waists; ants have narrow waists. 3. Termites have four long wings of equal size and shape; ants have two large forewings and two smaller hind wings.

What are social insects?

Insects like termites and ants that live in family groups called colonies. Within the colonies, specialized groups of termites or ants (castes) perform jobs that benefit the colony as a whole. In the termite colony, the worker caste does all of the foraging for food and is responsible for feeding the termite king, queen, and other siblings. The king and queen termites are responsible only for reproduction. The soldier caste is responsible for colony defense.

Name the three indicators of subterranean termite infestation.

1. The presence of mud tubes. 2. The presence of swarmers inside or next to the structure. 3. Wood damage where the springwood has been eaten away; galleries are filled with muddy frass.

What conditions lead to a subterranean termite infestation?

1. Wood-to-soil contact. 2. Form boards, grade stakes, and other items not removed after construction. 3. Wood debris left inside concrete masonry units (CMUs). 4. Wood refuse buried under the slab. 5. Low foundation walls where the sill plate and framing wood are below grade level. 6. Brick veneer or stucco below grade that hides termite entrance into the structure. 7. Foam board insulation that extends below grade and gives termites access to structural wood. 8. Soil-filled planters built against the foundation. 9. Paper and foam collars or sleeves around pipes and ducts. 10. Improper drainage around the structure, including short eaves and downspouts. 11. Mulch and landscaping against the foundation wall. 12. Wooden fences, trellises, and other landscaping materials placed against the structure. 13. Leaking pipes and air conditioning drip lines at the foundation. 14. Shrubs blocking crawlspace vents. 15. Heating units in the crawlspace that maintain warm soil temperatures year-round.

How can you tell a carpenter bee from a bumblebee?

A bumblebee's abdomen is covered in yellow hair. Because bumblebees are social insects, the worker caste has large pollen baskets on the hind legs to carry pollen back to the colony. Carpenter bees have black, shiny abdomens with very little hair. In addition, carpenter bees are solitary and do not live in colonies. Thus, they have no pollen baskets.

How do worker termites differ from swarmers in appearance?

In Virginia, termite swarmers (primary reproductives) are dark colored and have wings. The swarmers also have functional eyes and reproductive organs. Worker termites are milky white and have no eyes, wings, or reproductive organs.

Where would you look for carpenter ant nests around buildings?

In porch pillars, sill plates, windowsills, hollow-core doors, wall voids, foam insulation, wood scraps, wood fencing, and wood contacting the soil.

Describe the differences between incomplete (gradual) and complete metamorphosis.

Incomplete (gradual) metamorphosis is a type of insect development that has three life stages (body forms): egg, nymph, and adult. The nymph resembles the adult in body form. Complete metamorphosis is a type of insect development that has four life stages: egg, larva, pupa, and adult. The immature stages are wormlike and look nothing like the adult.

What type of damage do powderpost beetles do?

The adults lay their eggs in cracks or in the cells of wood. The larvae hatch out of the egg and burrow into the wood. Once inside, the larvae will eat their way through the wood for one to two years. Because of their wood consumption, powderpost beetle larvae can damage joists, subflooring, hardwood flooring, sill plates, and furniture. After pupation, the adult beetles emerge by chewing their way out of the wood, causing shot holes in the wood surface.

Why are lyctid, anobiid, and bostrichid beetles often called powderpost beetles?

The larvae of these beetles produce powdery frass as they chew up the wood.

What is the most troublesome longhorned beetle in Virginia? Why?

The old house borer. This insect can damage timbers in both new and old houses. It prefers to infest the sapwood portions of softwood species such as pine, spruce, and fir. Therefore, this beetle is most likely a greater pest of new construction than of older homes, despite its name. Because of the long life cycle of this insect, an old house borer infestation often spans several decades. These beetles also reinfest wood after emergence and can cause serious damage to structural wood over time.

The brick veneer of your client's home extends below the graded soil. Why is this a problem?

You cannot easily detect the presence of invading termites until the wood damage becomes obvious. In addition, wood structures in direct contact with the ground such as decks or porches invite termites.