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Ruguloscolytus rugulosus (Müller)
Scolytus rugulosus

Insecta, Coleoptera, Scolytidae .

Fruit bark beetle, Shot-hole borer

Description, Biology, Life Cycle, Damage, Common Names, Images


[R]Description
-Adult: 1.8 to 2.4 mm, dark brown, sometimes slightly reddish towards the back, stocky. Very close-set punctation of the elytra pressed down in slight furrows (*) .

[R]Biology
- This beetle develops for preference on stone-fruit trees: plum, apricot, peach, cherry, more rarely on apple, pear, quince. It also attacks elm (Ulmus), hawthorn (Crataegus), sorbus (Sorbus), hazelnut, birch (Betula), etc.
- Adult: flies directly it emerges. Once it has found a host plant, the female bores a vertical egg-laying gallery, 20 to 30 mm, between the wood and the bark. Mating takes place several times during this, the male remaining at the entrance of the gallery to keep rivals away. Laying spreads over 20 to 30 days, at a rate of 2 to 3 eggs a day. Average fecundity: 55 eggs.
- Larva: immediately after hatching, each larva drills a gallery at the boundary between the wood and the bark it feeds on (*) . The larval galleries radiate away from the maternal chamber, they are sinuous and often cross each other at their extremity. Their diameter increases with the larval growth. The larva pupates in a small chamber at the extremity of the gallery (*) .

[R]Life Cycle
- 1 generation at the latitude of the North of France, 3 in the warmer regions of the Mediterranean coast.
- The adults appear from May to end of July. The larvae develop during the spring and summer and, according to the region, can pupate and produce a new generation. As winter approaches, the larvae enter into diapause in the small pupal chamber. Those which were unable to build this small chamber die before pupating which takes place end of March.

[R]Damage
The galleries are located principally in branches of a diameter of 3 to 4 cm as well as at the top of young trunks. Drilling galleries impedes the circulation of sap and brings about the death of the attacked plant or branch. Attacks are more frequent on trees already weakened by drought, fungal diseases or pests.


[R]Common Names
DE: Kleiner Obstbaumsplintkäfer, Runzeliger Obstbaumsplintkäfer ES: Escolítido rugoso o pequeño escolítido de los árboles frutales FR: Scolyte rugueux, Petit Scolyte des arbres fruitiers IT: Piccolo scolito degli alberi da frutto, Scolitide dei frutti. PT: Caruncho das fruteiras GB: Fruit bark beetle, Shot-hole borer

[R] Images

  1. Ruguloscolytus rugulosus (Müller) (Coutin R. / OPIE)
    Damage on a branch of a plum tree On the upper branch, adult entry holes (a). At the bottom, egg-laying maternal gallery (b) from where the larvae will excavate their own galleries.
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  2. Ruguloscolytus rugulosus (Müller) (Coutin R. / OPIE)
    Pupa in its cell The larva has prepared its pupa cell at the end of its gallery filled with dry frass.
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  3. Ruguloscolytus rugulosus (Müller) (Coutin R. / OPIE)
    Larva at the end of its gallery A part of the bark has been removed to show the gallery, full of dry frass.
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  4. Ruguloscolytus rugulosus (Müller) (INRA)
    Adult ready to exit its pupa cell The branch has been debarked to show part of the gallery network (arrowed) and a new adult ready to emerge.
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