Assessing the aggressiveness of bark- and wood-boring beetles colonising girdled Scots pine trees

128 Scots pine trees (Pinus sylvestris L.) were girdled on four different dates in April 2007, July 2007, October 2007, and January 2008. Colonisation of the girdled trees by bark- and wood-boring beetles was examined during two vegetation periods following the treatment. The time elapsed from girdling to the first attack of bark- and wood-boring beetles was 1−19 months (mean = 10.7) and differed significantly among trees girdled on different dates. The colonisation of trees began most frequently in the upper thin-barked part of the trunk and in thick branches. In total, 32 species of bark- and wood-boring beetles colonised the studied trees. Particular species were significantly associated with certain periods of tree dieback and colonisation. Phaenops cyanea (F.) and Pissodes piniphilus (Hbst.) were by far the most aggressive first-colonising species capable of attacking relatively vigorous trees with low needle loss (approximately 35%). Pityogenes chalcographus (L.), Ips acuminatus (Gyll.), and Tomicus minor (Htg.) were shown to be moderate-aggressive species, followed by Tomicus piniperda (L.), Monochamus galloprovincialis (Germ.) and Pissodes pini (L.). The remaining ten assessed species (including the putative pests Arhopalus rusticus (L.) and Pityophthorus pityographus (Ratz.)) were designated as not harmful and saprophagous arriving on trees that have previously been colonised by the aforementioned species.

This study was supported by the Ministry of Education, Youth and Sports of the Czech Republic, Project No. MSM 6215648902 and by OP Education for Competitiveness (European Social Fund and the state budget of the Czech Republic), Project No. CZ.1.07/2.3.00/30.0017 Postdocs in Biological Sciences at MENDELU.