Leś. Pr. Bad., 2009, Vol. 70 (4): 355–361.

Kornik modrzewiowiec Ips cembrae (Heer) (Coleoptera, Curculionidae, Scolytinae)
w młodnikach i starszych drzewostanach modrzewiowych południowej Polski
The larch bark beetle Ips cembrae (Heer) (Coleoptera, Curculionidae, Scolytinae)  in young and older larch stands of southern Poland

Wojciech Grodzki
Instytut Badawczy Leśnictwa, Zakład Gospodarki leśnej Regionów Górskich, ul. Fredry 39, 30-605 Kraków; Fax +48 122528202, e-mail: W.Grodzki@ibles.waw.pl
Abstract. During 2006–2008 an increase in the occurrence of Ips cembrae was recorded in old stands of southern Poland, mostly in the area of Regional Directorates of State Forests in Katowice and Wrocław, where the volume of infested trees removed from the stands increased in 2007 by almost 7 times compared to 2006. Stands with a high proportion of larch as well as the younger and youngest ones (up to 60 years) were more infested than mixed ones; larch growing on poor and humid sites was less susceptible to the infestations than on rich and dry ones. Intensive infestations were also recorded in young larch stands in two regions of southern Poland: in the Sudeten mountains at altitudes of 700–1100 m a.s.l. and in Silesia (~200 m a.s.l.), in areas reforested 15–20 years ago. The bark beetles infested 11% of young trees felled during thinning; maximum frequency was 56,5%. An origin of this outbreak was thinning without tree removal, which created favourable breeding conditions for the bark beetle.  An area of potentially threatened young stands was estimated to about 10,5 thousand ha, and the damage caused by I. cembrae in such young stands generated a new problem for forest protection.

Key words: forest protection, pest outbreak in young stands, site conditions.