The small and the large wood beetle
There are 2 types of wood beetle : the small and the large. Both can cause considerable damage to a house. Wood beetles are xylophagous insects, meaning that their larvae move through the wood, digesting the cellulose and digging small round holes measuring 2 to 5 mm. You'll find traces of its passage on sculptures, paintings, old furniture, etc. These are often made from the sapwood of the wood. It can also be found in old books and archives. In this dossier, you will find a range of answers and natural products to help you combat this insect.
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Latin name : Anobium punctatum, Xestobium rufovillosum
Order : Coleoptera
Family : Anobiidae
Size = 2.5 to 5 mm
Larva small beetle = 5 to 7 mm
Size large beetle = 5 to 7 mm
Large furniture beetle larva = 6 to 11 mm
Location : in woodland
Period : all year round
The larva is a small, soft, hairy white worm that gives rise to a hard, stocky red insect with antennae ending in a small club.
What you need to know about the wood beetle
Two species are mainly found in homes : the small wood beetle and the large wood beetle. They can be found in furniture, lumber and flooring. Unlike capricorn beetles, wood beetles do not live permanently in wood. To get in and out of the wood, they drill circular holes a few millimetres wide (small beetles = 1 to 3 mm, large beetles = 2 to 4 mm). These holes are very characteristic of old furniture.
Anobium punctatum - small wood beetle
Development cycle : Adults emerge from the wood from mid-May to the end of August. They live for 15 to 30 days and do not feed. After mating, the female lays 20 to 40 eggs in cracks in the wood. The larval cycle lasts 3 to 5 years on average. The adult exit holes are round, 1 to 3 mm in diameter.
Xestobium rufovillosum - large wood beetle
Development cycle : Adults emerge from the wood between April and May and live for 9 weeks. After mating, the female lays around a hundred eggs in cracks and crevices in the wood. The larval cycle lasts from 1 to 10 years, in wood that is already infested with decay fungi. The galleries dug by the larvae are round. The exit holes are round, 2 to 4 mm in diameter. The worm is lenticular in shape.
Adult beetles enter houses by flying. The female lays eggs on the wood in summer. The young larva burrows into the wood to feed. When it reaches adulthood, it will emerge from the wood.
The larval cycle is highly variable, depending on the humidity, temperature and nutritional quality of the wood. It can last from 1 to several years.
The adult life of the furniture beetle is dedicated solely to reproduction. It does not feed and lives for a few weeks, just long enough to reproduce.
The death watch beetle can attack many types of wood, including birch, hornbeam, alder and poplar. They are more likely to attack old wood or wood that has been altered by fungi, but rarely oak or pine heartwood.
As the death watch beetle cannot live in a permanently dry environment (<50°TH), it is more likely to be found in damp places and rarely in heated rooms. For the death watch beetle, damp wood is essential for its development.
At certain times of the year, these insects call out to each other at the same time every day, striking the wood with their heads. These noises, audible from the outside, have earned the death watch beetle its nickname.
Even if the beetle won't destroy a piece of furniture or a floor quickly, you should know that if you let it proliferate, its numbers can increase 10-fold in 10 years !
For full diagnosis and treatment methods, read our special report on the subject.
Small pieces of wood (obviously not your frame!) can be put in the freezer.
If possible, try to reduce the moisture content of the wood (drying, ventilation, heating).
According to the regulations, wood treatment products against wood-eating insects, whether preventive or curative, must contain at least one active ingredient belonging to biocide class TP8.
The problem is that there are currently no authorised natural active ingredients in this class.
Most wood treatment products contain cypermethrin in combination with a solvent (white spirit, citrus, water, etc.). Whether they have an odour or not, these treatment products containing components of petroleum origin are not very healthy in a place where we live !
But a beetle is an insect. And to kill an insect, you use an insecticide that must be in class TP18.
So you can use a natural insecticide to kill beetles. This insecticide will have no wood protection function, unlike wood treatment products. But it will get rid of the beetles.
Although it may seem obvious, don't try to treat waxed, painted or varnished wood. To be effective, the treatment must be applied to untreated wood.
The solution, which is a little time-consuming but effective in killing beetles, is to work the insecticide into the holes made by these insects (syringe, spray, sponge, mop).
There are 3 products that can help
1 - Our 4J All Insects insecticide (4J at 5%). This 500 ml spray will treat around 5 m2. For larger surfaces, use the same product in its concentrated form. In this case, you'll need to dilute the product by 5% with water. Note that this product, based on plant pyrethrum, has a fairly short remanence. It will therefore be effective for rapid curative action, but not for long-term curative action. As soon as the insect comes into contact with the 4J product, it will die instantly (pyrethrum's neurotoxic effect). The difficulty remains in reaching these insects, which often take refuge in the heart of the wood. The best results are obtained by injecting the product (using a small syringe) into the largest holes left by the insect.
2 - Margosa extract. Margosa's main property is to render all treated surfaces unfit for insect consumption, so the insects either have to leave the treated area in search of food, or starve to death. Thanks to its broad spectrum and long duration of action, Margosa is effective in most infested areas. It can be applied by spraying or injection. Margosa blocks the development of larvae, disrupts the search for food and sterilises adult insects. The treatment should be carried out by spraying the wood or injecting it directly into the holes at a concentration of 2% for preventive use and 4% for curative use.
3 - Diatomaceous earth spray. If the holes (galleries) left by the insect in the wood are large enough (over 2 mm), diatomaceous earth spray can be used. Thanks to its applicator tube, you can apply the diatomaceous earth to each hole and inject it as deeply as possible. Thanks to the specific surface area of its grains and its siliceous skeleton, diatomaceous earth is formidable in the fight against crawling insects :
a - Ingestion of the silica particles (which are very sharp) by insects causes lesions in their digestive tract.
b - The fineness and hardness of the silica particles collected by the insect's bristles cause lesions on its limbs or carapace. This causes the insect to lose body fluids, leading to death from dehydration after a few days. The absorbent properties of diatomaceous earth (up to 150% of its weight) encourage this process.
N.B.: Obviously, if the beetle infestation is severe and your wood has been under heavy attack for years, you will need to call in specialist, approved companies to carry out a full diagnosis and come up with appropriate solutions.
Frequently asked questions about wood beetles
R: It depends on the surfaces to be treated. If it's a small cupboard, for example, you can use our Ecodoo All Insects aerosol or our 4j spray diluted to 5% for large surfaces. Alternatively, you can use our pure 4j diluted with water. If it's a parquet floor, the most effective way is to "wash" the floor with our 4j. If it's a piece of furniture, spray the 4j on the inside + possibly treat the holes with a syringe on the outside.
R: You can use our 4J insecticide ready to use or pure to be diluted, for the use it depends what you want to treat if it is a piece of furniture (if waxed furniture: treatment inside with a spray + if necessary inject with a syringe in the holes on the outside) or other ...
R: The products presented in our dossier on woodworm have indeed shown good results (4J, margosa extract and diatomaceous earth spray).
R: You need to treat the inside of the wood with insecticide using a brush or sprayer (2 coats 24 hours apart). If you're brave enough, you can also inject insecticide into the outside holes (syringe).
R: Any liquid insecticide will do, but you need to treat the inside of the furniture with a brush or spray; allow for 2 coats 24 hours apart. On the outside, if you're brave enough and if it's badly affected, you can inject insecticide into the holes with a syringe.
R: Wood beetles or longhorn beetles ? In both cases you can use our 4J insecticide, but if the galleries are deep you may have to inject your beams.
R: You can use our 3% 4J insecticide, but to be effective you'll need to get the product into the holes made by the beetles.
R: I don't know of any essential oil that could kill or even keep away beetles, but why not, if you know of any I'd be interested.
R: We do have an insecticide that can be used to treat furniture, but it's totally different from natural xylophene, which is not a synthetic product, is a water solvent, not a petroleum distillate, and is non-neurotoxic. Treating by capillary action is one solution, but I'm not sure that the product can treat the whole piece of furniture, or else it will take a long time.
R: The same reaction as if you washed your floor with water !
R: If it's a water-based paint, you can dilute 5% of 4J with 95% of the paint, but we've never tried this method. Personally, I'd treat the wood with insecticide, leave it to dry and then paint over it.
R: For example, you can use our insecticide "Insecticide for all insects" (4J at 5%), but you have to treat inside, otherwise the wax will prevent the product from penetrating the wood.
R: In general, only the affected wood is treated. It is not necessary to treat healthy wood.
R: We've had good results with our "all insects" insecticide, but woodworms generally only eat wood or certain types of paper, but not wool carpets. If this is the case, you should start by treating your parquet floor by getting the insecticide into the holes in the parquet.
R: In damp wood, you'll mainly find furniture beetles, especially if there are small holes with light sawdust.
R: Your problem is a complex one, since the moths are already in the wicker, so the treatment product has to come into contact with the insect. In this case, the most effective solution would be to soak all your baskets in a bath of insecticide, but I don't know if this is technically feasible.
R: Ecodoo All Insects insecticide is based on plant pyrethrum and essential oils. This product is only dangerous for cold-blooded animals (fish, snakes, etc.) but not for mammals.
R: Small holes in wood with sawdust are probably beetles, as they reproduce in July and August when it's hot. If your wood is waxed, you'll have to treat hole by hole with a syringe !
R: A small round hole in a parquet floor is probably caused by a furniture beetle, but are you sure that the hole is recent? Summer is the time when furniture beetles breed, so it's quite possible.
R: You must not have read it correctly: you drill holes when you inject beams but not parquet, for furniture you inject insecticide into existing holes with a syringe, for parquet you can treat with a syringe, a brush, a roller or a mop. I don't think woodworms like turpentine, but I'm not sure it kills them !
R: Wood treatment products belong to class TP8 and since the new regulations, natural insecticides are no longer authorised for treating wood. Wood bliss is not an insecticide, but in theory it mineralises the wood.
R: To be effective, the product has to be able to penetrate the wood well. Pistal, which is very effective, contains paraffin, which is a rather "heavy" product and I'm not sure that it will penetrate the wood well. Margosa-based wood treatment products are beginning to appear on the net. I'm not sure how legal this is, as margosa extract is tp19 but not Tp8! Margosa is interesting for treating plants and it's likely that it will also work on wood. We sell margosa extract on our site, which will have this repellent action.