Occurrence of the Invasive Bark Beetle Phloeosinus aubei on Common Juniper Trees in the Czech Republic

Tomáš Fiala,Jaroslav Holuša

doi:10.3390/f10010012

Abstract

The small cypress bark beetle Phloeosinus aubei is considered an invasive pest in several central European countries, and we have determined its current distribution on common juniper trees (Juniperus communis) in the Czech Republic. The results indicated that P. aubei is widely distributed in the country but is more common in the east than in the west. The beetle was mainly detected on older, damaged trees and on stems with diameters > 3 cm. The apparently widespread and abundant populations of P. aubei could explain infestations of the beetle on Thuja spp. and Juniperus spp. in gardens (three confirmed cases during the last 10 years). We consider P. aubei to be a potential pest on older, naturally occurring J. communis in protected areas where its population density could increase on weakened and damaged trees. We suggest that P. aubei can be monitored via simple inspection of dying and dead J. communis trees in the field.

Highlights

Bark beetles (Coleoptera: Curculionidae, Scolytinae) are among the most damaging pests of trees, because the adults and larvae tunnel beneath the bark; such tunnelling can eventually girdle and kill hosts
Phloeosinus aubei was found in all localities in the eastern part of the Czech Republic but in only about half of the localities in the western part of the country (Figure 3); this trend was statistically significant (χ2=14.89; p < 0.001)
The habitats were different in eastern vs. western parts of the country: protected areas were regularly maintained by grazing or cutting in the eastern localities but were overgrown with Frangula alnus Mill., 1768, Prunus spinosa L., 1753, Rosa spp., and other species in the western localities (Figure 4, Appendix A)

Summary

Introduction

Bark beetles (Coleoptera: Curculionidae, Scolytinae) are among the most damaging pests of trees, because the adults and larvae tunnel beneath the bark; such tunnelling can eventually girdle and kill hosts. The number of generations per year ranges from two to four in the Mediterranean and Pontic areas [14,15,16], where the beetle overwinters as adults [14] and larvae [16] and begins to swarm when the temperature increases to 12 ◦ C in the spring [15]. In Central Europe, in contrast, P. aubei has only one generation per year [17,18], overwinters mainly in the adult stage [18,19], and begins to swarm when temperatures exceed 20 ◦ C [20]. In the Mediterranean area, P. aubei is an important pest, because it attacks and can kill host trees [21]

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