European shot-hole borer - Anisandrus (Xyleborus) dispar and other species
Symptoms / species
Impact / measures
Death of branches, stronger twigs or young trees; early stage of infestation: ejection of wood shavings, later on numerous round emerging holes, often in groups; most common Anisandrus dispar: galleries: primary tunnels, following the annual rings and shorter ones, extending in axial direction; development of the beetles - depending on the amount of the material - up to 6mm depth in the wood; imago: sexual dimorphism – female 3,5mm, male 2mm. Imagines and larvae feed from Ambrosia-fungi, which grow in the humid and warm microclimate of the tunnels; only one generation per year (flight time April/May); possibilities of errors: other species of beetles developing in the wood.
Affected tree species
Ash; Maple; Oak;
Stem; Shoot/Twig/Branch; Shoot/Twig/Branch;
Attacks mostly following weakening of the plant (for instance heat necroses of thin-barked broadleaved trees); consequences: timber – technical devaluation; with young trees heavy attacks may cause the death, in general only twig- and branch dieback.
Curative measures Mostly hygienic measures sufficient; in commercial orchards ethanol containing traps or insecticides (see Official Register of Plant Protection).