Termites and other wood-destroying organisms (wood-destroying beetles, wood-decaying fungi and marine borers) have an important role in nature — they decompose wood and plant materials, recycling nutrients back into the environment for plants to grow. In the urban environment, however, termites and other wood-destroying organisms are largely undesirable. They can cause significant economic loss, injure trees, require broad use of insecticides and interrupt peoples’ lives. They can cause important economic losses , damage trees, need important quantities of biocides to eliminate de pest, and influence the life of people.
The most damaging animals that attack wooden structures are the termites. The beetles are the next most important group of insects which attack wood. On the basis of distinctive habits and problem solving challenges, the beetles rank near the top
Economic losses from pileworms (mollusks) and certain crustaceans occur in many areas where wood, concrete, and other materials come in contact with sea water. Fungi are also an important source of damage to wooden structures in areas where the climate is normally quite warm and humid. Wood rotting fungal spores are found everywhere and are instantly prepared to germinate as soon as suitable environmental conditions prevail
Carpenter ants are frequently found emerging from wooden structures
There is no “magic bullet” for this problem! It requires the use of several tools integrated into a comprehensive, long-term, multi-tactic IPM approach over large areas to develop a sustainable solution.
There is no one treatment to solve all the problems related with wood destroying organisms. There are different control strategies associated with different pests, different sites and different treatment possibilities. Normally it will require the use of several tools integrated into a comprehensive, long-term, multi-tactic IPM approach over large areas to develop a sustainable solution
a. Wood Fungus
Decay fungi can cause severe structural damage to any wood member, even wood species such as redwood and cedar. Every year they cause at least as much damage to structures as termites. All that is needed is a source of water in contact with the wood. Decay will occur in untreated wood in direct contact with ground, cement or concrete, or exposed to a source of moisture such as rain seepage, plumbing leaks, or condensation. Wood kept dry will never decay.
Once decay has started in a piece of wood, the rate and extent of deterioration will depend on conditions such as temperature and moisture content. Under suitable conditions, most fungi species develop fruiting bodies of various shapes, colors and sizes, These fruiting bodies contain enormous numbers of microscopic spores which act like seeds. If a spore comes in contact with a suitable material such as moist wood, it can germinate and spread the infestations. Many people exhibit allergic reactions to fungal spores.
Types of Wood Fungus:
- Brown & White Rot Fungi. Brown and White Rot Brown rot fungi feed on the wood’s cellulose, a component of the wood’s cell wall, leaving a brown residue of lignin, the substance which holds the cells together. Infested wood may be greatly weakened, even before decay can be seen.
- Water Conducting Fungi. Most decay fungi are unable to conduct water very far and can only attack moist wood. However, Poria incrassata, called dry rot or the water-conducting fungus, will decay wood which would not be attacked by typical decay fungi. Poria infested wood is often mistakenly identified as subterranean termite damage. This type of fungus can transport water for up to 30 feet through large root-like structures call rhizomorphs. They attack softwoods such as pine, spruce, and fir. Once established, it can quickly spread through a building and destroy large areas of flooring and walls in as little as a year or two. Typically, infestations of Poria begin in earth-filled porches, damp crawlspaces, and basements where wood is in contact with the soil, moist concrete, or damp bricks.
- Molds and Stains.Molds and stain fungi are sometimes mistaken for decay, and while they may discolor wood, they cause no structural wood damage. The presence of molds and stains, however, is a sign that conditions are favorable for decay fungi and a preventative treatment may be necessary. In addition, molds can increase the capability of wood to absorb moisture, opening the door to attack by decay fungi.
Termites are primitive organisms, they exist even before ants. That’s why we could probably think that ants adopted and copied the complex social structure from termites and not the other way around. We can see today that the termites that live now are not very different from the ones that lived in our planet many years ago.
Broadly speaking, termites can be divided into four big groups, according to the way they build their nests. There are, humid wood termites, drywood termites, subterranean termites and arboreal termites. From the around 2600 known termite species, only a few of them constitute real pests. In fact, there are many species that don’t even eat wood but humus, herbs and lichens. Other species can’t survive living outside their natural habitat in jungles or meadows.
The termites have an incomplete metamorphosis which differentiates them from other social insects such as ants or wasps that have a complete metamorphosis. This means that the juveniles that emerge from the egg, show great resemblance with the adults, and through different molts will grow up in size and will, finally, reach the full appearance and size of an adult.
These insects are divided in castes or groups of individuals that have different functions. Subterranean termites have three castes: workers, soldiers and reproductive. Drywood termites and Humid wood termites don’t have real soldiers.
The termite workers can be separated into two groups: termite workers that gather food, (are sterile) and functional termite workers that can be either male or female. This last group, can change and become soldiers, winged or secondary reproductive termites, depending on the colony’s needs. The workers keep the colony, build the nest, maintain it, search for food and feed the entire colony.
The soldiers are sterile and their only function is to protect the colony. They have such large heads and big mandibles that the soldiers must feed them. They are always in small numbers when compared to the quantity of termite workers.
The reproductive termites are represented by the primary reproductive and the secondary reproductive. The primary reproductive are the queen and king, the founders of the colony. The queen can live for even more than 30 years. The secondary reproductive appear on mature colonies. They are wingless and produce eggs which allows the colony to grow quicker. If the primary reproductive disappear, the secondary can replace them.
The members that can produce bigger damage include:
- Drywood termites. These are a group of termites that build their nests inside non humid wood. They belong to the Kalotermidae family, which include different genera and that are considered primitive termites. This genera include Cryptotermes, Neotermes, Glyptotermes, Incisitermes and Kalotermes. The most extended and well know specie is probably Cryptotermes. Drywood termites are also known as powder post termites or furniture termites because they are frequently found infesting different kinds of furniture. This termites live inside wood that has no contact with water They have the curious ability of being able to metabolize water from the wood they are feeding on, absorbing and re-absorbing water from their feces, depending on their necessities. In high humidity conditions, drywood termites will excrete liquid feces, but in low humid conditions, they’ll re-absorb the humidity of their intestines and will excrete feces with the form of a small pellet. This excrements are characteristics of this group of termites.
- Subterranean termites. Subterranean termites are those termites that build their nests under soil. Termites build their nest in different ways, but excavating under the soil is the most common way for many of the termite species. Nesting under soil has many advantages, and among them, there is the possibility of living with humans in environments that have been modified by them. This adaptability can generate problems between termites and humans. Not all the subterranean termites are destructive. The ones that cause more damage are those that can thrive in urban areas, can create big colonies, and their nests, since are found under the soil, are difficult to be detected. From their subterranean nests, they can move in any direction trying to find wood. This termites have the habit of constructing mud tubes that offer them shelter when they have to be exposed. This mud tubes are easily seen in case of heavy infestations. They allow them to cross through exposed areas without being seen, while they also protect them from desiccation. Since they live underground, they are paled colored. Subterranean termites preferably feed on spring wood. Summer wood contains lignin which is difficult to digest. Therefore, wood is damaged in different stratus or layers and normally sand is found in the galleries.
c. Wood destroying Beetles.
The beetles that infest wood, in nature help reduce the dead trees and transform them in ways that can be used as nutrients for plants. But some of this beetles can cause heavy damage for wood used in structures or furniture. Normally it’s not easy to find the adults and/or the larvae. Therefore in order to detect if there’s and infestation we will search for evidence that will allow us to identify the type of pest that might be affecting you. The most important clues that we will find, include:
- Type of damaged wood: soft or hard wood
- Age of the wood: old or new
- What is being damaged: structural beams, boards, manufactured products, etc.
- Exit Holes done by the adults: control size and shape
- Texture and type of powder that we find in tunnels and galleries.
- Humidity content of wood.
What must be done is, at least, find the beetle family that’s infesting the wood. Once identified, we will decide which will be the best control strategy for each pest.
|Type of Beetle||Damaged wood. Parts and types||Inspection of the damage|
|Exit Holes||Galleries (tunnels)||Powder|
|Anobiid Beetles (Anobiidae) Common Furniture beetle||Sapwood from hard and soft wood: rarely in heartwood||Circular: 1,6 – 3 mm diameter||Circular, up to 3mm diameter; numerous; randomly arranged||Fine Powder with conspicuous granules, elongated. Congested without cohesion|
|Bostricid beetles (Botrichidae)||Mainly sapwood from hardwood; not often softwood||Circular: 2,5 – 7 mm diameter||Circular 1,6 -10mm diameter; numerous; randomly arranged||Fine to thick powder, congested granules; tends to attach|
|Lictyd Beetles (Lyctidae) Powder post beetles||Sapwood from annular cut (and sparse), hard and porous wood||Circular: 0,8 – 1,6 mm diameter||Circular, 1,6 mm diameter; numerous; randomly arranged||Fine, flour-like, loose in tunnels|
|House longhorn beetle (Hylotrupes bajulus)||Sapwood of softwood, preferablyPine tree.||Oval: 6 – 10 mm diameter long||Oval, up to 10 mm diameter long, numerous in exterior sapwood; undulated marks on walls||Very fine Powder and very small granules; congested in tunnels|
|Curculionidae||Sapwood and hardwood from softwood and hardwood||Irregularly rounded and elongated||Circular,up to 1,6 diameter||Very fine Powder and very small granules; very congested|
IPM approach requieres the follwing steps:
- Thorough inspection. It’s important to determine the kind of wood destroying organisms that infest the area. We will drive visual inspections, use traps, use sound detectors, moist measurers, etc..
- Determine the infested areas. Try to find the source of the infestation and act accordingly. None affected area should be left without inspection but also we have to detect if there are non-affected areas that don’t need treatment or any kind of preventive measure
- Decide the best control measures prioritizing the use of preventive measures and pest proofing. There are many possibilities: reducing moisture, sealing cracks and crevices, repairing leakages, assuring a correct water flow in case of rain, etc..
- When a treatment has to be done, first try to use the less risky approach (for humans, non-target species, and the environment): use of traps, use of biorational biocides, of biological approaches, and when necessary use traditional chemical insecticides or fungicides.
- Make a complete report of what’s going to be done, how and when. Always make sure that all preventive measures are written down and are understood by the customer.
- Explain the customer in plain language what the strategy is about and the advantages of the chosen one against other possibilities. Educate the customer.
- Make follow up inspections. Make sure that the system is working and that pests are managed properly according to the standards agreed with the customer. Make sure that the structural measures that have been implemented are working and are properly maintained.