Bark beetles of Cupressaceae - Phloesinus thujae, Phloeosinus aubei
Symptoms / species
Impact / measures
Crown decline or death of the whole tree; on the bark numerous entrance and emerging holes of beetles, underneath bark galleries: mostly dubble arm-shaped, rather star-shaped longitudinal tunnel (up to 5cm in length); pupation deep inside the springwood; both species small (1,6-2,4mm), brown to black; generation-cycle one year; flight period of the adults mid May to June; the young beetles mostly enter in branch forks (shavings, resin flow) and mine the lateral shoots (ca. 0,5 – 1cm in length – maturation feeding); attacked twigs turn yellow and easily break off.
Attacks in general only of weakened plants, beetles can change into primary agents in case of intense propagation; during the maturation feeding only optical impairment, the following feeding (from a twig diameter of ca. 3cm on) causes the decline of plant parts or the whole plant.
Curative measures Maturation feeding: hygienic measures: removal of the infested branches, as long as the beetles are present in the shoot (until late autumn); feeding for breeding: removal of the plants, as long infestation is observed.