Distribution of the double-spined spruce bark beetle Ips duplicatus in the Czech Republic: spreading in 1997–2009

Abstract

Ips duplicatus (Coleoptera: Curculionidae) was reported in the Euro-Siberian taiga from Sweden to Sakhalin and in the Alps at the beginning of the 20th Century. It has been recorded in spruce stands in the north-eastern part of the Czech Republic since the beginning of the 1970s; monitoring of I. duplicatus was conducted in the Czech Republic in 9 years between 1997 and 2009. Beetles of the overwintering generation were captured in Theysohn pheromone traps baited with a lure of ipsdienol and E-myrcenol, and after 2005 in ID Ecolure lures. Surprisingly, I. duplicatus was found throughout the Czech Republic already in 1997. In 2002, there was a nationwide decrease in their numbers. Particularly since 2005, there has been a spread from the main center of occurrence in the eastern areas to the south and west into the central part of Bohemia where, until that time, its population densities had been lower and had not caused economically significant damage. Moreover, it was observed that in the north-eastern parts of the Czech Republic up to 80% of spruce trees from sanitary felling had been infested by this pest in recent years. The recorded amount of spruce trees infested by I. duplicatus is correlated significantly with the amount of spruce trees recorded as damaged by Ips typographus, Ips amitinus and Pityogenes chalcographus infestation as well as with the numbers of individuals of I. duplicatus captured during the aforementioned monitoring.