WOOD PEST SPECIES

Recognise wood pests

Wood-eating insects originally had the task of converting dead plants and trees back into humus. Historically, some have “followed” people into the buildings, where some species have specialised in very dry woods.

Since wood has very little protein than other foodstuffs, the development time of the larvae (worm-like) is quite long, from a few months to many years – and usually remains hidden in the wood. In addition, the amount of wood that has to be eaten to develop into a beetle is considerable, which causes significant damage.

Bamboo drill

(Dinoderus minutes)

bamboo beetle

Look

  • The shape of the dark brown coloured beetle is compact to cylindrical and has a body length between 2 and 3.7 mm.
  • The antennas are greatly enlarged on the last three antenna elements and form a separated sensor lobe.
  • The pronotum arches over the head in a spherical manner and is granular in the shape of teeth on its round front edge. There are two shallow pits at the rear edge of the pronotum.
  • The elytra are strongly dotted and hairy.

Reproduction

  • On average, 27 to 35 eggs per female are laid on the food substrate, and the hatched larvae burrow into the interior.
  • The larva spends its development over approx. Four stages until pupation within the infested material.
  • Under optimal conditions, the development cycle can be completed in 60 days (35 ° C, 75% RH), leading to several generations per year.

Way of life

  • The bamboo borer is an imported wood insect.
  • The beetle larvae mainly damage bamboo cane. But they can also multiply on cassava roots.
  • Typical is the creation of tubular passages along the plant fibres and circular loopholes in the beetles.
  • The introduction of the species originally from East Asian countries also occurs via shipments (e.g. tapioca products) and packaging materials made of wood and even wooden musical instruments.

Blue fur beetle

(Korynetes caeruleus)

Blue fur beetle

Look

  • The size of the blue fur beetle is approx. 4 mm.
  • According to its name, the blue fur beetle is coloured metallic blue and hairy.
  • The larvae of the blue fur beetle are whitish and have a brown head capsule with a Y-seam.

Reproduction

  • The female fur beetle lays its eggs on the surface of the wood or the inside of exit holes.
  • The larvae live in woods that have been damaged by wood-borne insects. They feed on the larvae of these insects.
  • As soon as the blue fur beetle is fully grown, it reproduces, lays eggs and dies.

Way of life

  • The blue fur beetle is an antagonist, i.e. a beneficial insect, as it is the natural enemy of the common rodent beetle and the colourful rodent beetle.
  • Its presence, therefore, presupposes the existence of rodent beetles.
  • The larvae of the blue fur beetle hunt the larvae of the rodent beetle. The nail is cleared from the corridors – this shows the activity.
  • The blue fur beetle is unable to damage the wood.

Colourful rodent beetle (colloquial: dead clock)

(Xestobium rufovillosum)

Rodent beetle

Look

  • The colourful rodent beetle reaches a size of 5 to 7 mm.
  • It is dark red-brown with unevenly distributed yellow-brown hair spots on the pronotum and elytra.
  • The antennas are short, with three enlarged end links.
  • The larvae are similar to those of the common rodent beetle and differ from them only in the eyespots – they have two pieces on each side.

Reproduction

  • The female rodent beetle lays a total of 40 to 60 pearly white eggs about 0.4 x 0.7 in clusters of 3 to 4 eggs each in the wood. The egg ripening takes about five weeks. The hatching egg larvae are very lively and move on the surface of the wood before they dig into the wood.
  • Fungal infested wood is necessary for developing the ovules; older larvae can also develop in healthy wood. The larval stage usually lasts 3 to 6 years.
  • The optimal development temperature of the larvae is between 22 ° C, and 25 ° C, the minimum humidity at which larval development is possible is 25%.
  • The larvae pupate in summer; the pupal stage only lasts three weeks. The beetles overwinter in the pupal cradles and hatch in the following spring.

Way of life

  • In the open air, the larvae of the colourful rodent beetle live in deadwood infected by fungi. You can find them in the wood in the house, where there was once a fungal infection.
  • Knocking on wood is done with the head and is used to find the sex partner, with both sexes hitting. This is where the name Totenuhr comes from.

Common rodent beetle

(Anobium punctatum)

common rodent beetle

Look

  • The 3 to 5 mm long rodent beetle is compact, oval.
  • The common rodent beetle is usually dark brown, occasionally lighter or black-brown. The pronotum, which is pointed upwards, is pulled over the head like a hood (fire helmet). The head is hidden underneath. The elytra are provided with longitudinal, clearly protruding rows of dots.

Reproduction

  • The female rodent beetle lays between 20 and 30 eggs in total. These approximately 0.3 mm long eggs are placed individually or in clusters in cracks. After about 2 to 3 weeks, the young larvae hatch, drill into the wood and live there for about 2 to 4 years.
  • The optimal temperature for the larvae is between 22 ° C and 23 ° C; the optimal wood humidity is 30%.
  • After a two to four week rest of the pupae, the beetles hatch and leave the wood through circular drill holes, whereby fine drill dust is expelled.

Way of life

  • As a destroyer of art objects, furniture, musical instruments and everyday objects, the standard wood beetle is one of the most common wood pests.

House buck

(Hylotrupes bajulus)

House buck

Look

  • The house buck reaches a size of 8 to 25 mm.
  • It’s black or brown. There are two shiny black calluses on the pronotum. There is one white-grey hair spot on each wing cover.
  • The yellowish-white, “notched” appearing larvae reach lengths between 15 and 30 mm when fully grown. They are elongated, oval in cross-section and taper sharply towards the rear.

Reproduction

  • Between July and October, the female billy goat lays between 50 and 600 eggs in 2 to 8 clutches in the cracked wood with its extendable laying tube. The eggs are about 2 mm small, elliptical and pointed at the ends.
  • Depending on the protein content, the larvae feed in the wood for 3 to 10 years until they reach maturity. In doing so, you cause the most significant static damage in the timber.
  • The beetle eats its way out of the wood after about three weeks of rest and leaves an oval hole. The male flies to the female, which lays eggs again.

Way of life

  • The house buck is particularly damaging to dry, protein-rich softwoods. Here it only eats in the sapwood area.
  • Although the roebuck is a native outdoor insect, it occurs mainly in houses, especially in roof structures. On the outside, it primarily develops in cable poles, fence posts and the like, provided they are made of suitable woods.

Sapwood beetle

(Lyctus brunneus)

Sapwood beetle

Look

  • The sapwood beetle reaches a length of approx. 4 to 5 mm.
  • It is red-brown and has a narrow, flat body.
  • The larvae of the sapwood beetle are ivory-white, narrow-headed and have three pairs of legs. The large breathing hole in the last segment of the abdomen is a sure sign of identification.

Reproduction

  • The female sapwood beetle lays an average of 75 eggs in the pores of sapwood. However, the eggs are only applied in types of wood with a high starch content to ensure that the larvae can feed.
  • The larvae then hatch after about 8 to 10 days and gnaw into the wood. Depending on the developmental conditions, the larval stage lasts between 3 and 18 months.
  • The sapwood beetle’s life cycle is usually between 3 and 6 years.

Way of life

  • The sapwood beetle is introduced with tropical woods.
  • Of the four life stages that the sapwood beetle goes through, it causes the most significant damage in the larval stage. It bores through imported and deciduous woods for about 1 to 2 years.
  • It is active in flight in the dark and can survive in the wild.