Acta Scientiarum Polonorum
Silvarum Colendarum Ratio et Industria Lignaria

Abstract From among 392 Picea abies trees growing at the height of 700-800 m above the sea level in the Beskid Sądecki mountain range of the Carpathians (49o35’ N, 19o31’ E, southern Poland), infested by cambio- and xylophagous insects, 110 (28.1%) were also attacked by Ips amitinus (Eichh.). This bark beetle infested most willingly the weakened standing trees of age classes III-V (i.e. 41-100 years old) as well as trees recently overthrown, broken, and felled. It was most abundant in the middle part of the stem where the bark was 2-3 mm thick, infesting 38.4% of its length on the average. On a single tree I. amitinus always occurred in associations of cambio- and xylophagous insects composed of 2-12 species. There was only one generation of I. amitinus in the year, composed of the main brood and the sister brood. Its life-cycle is presented against a background of phenology of forest plants. There were three larval instars. Dimensions of all developmental stages and individual components of brood galleries are also given. I. amitinus plays an important role in killing weakened P. abies trees. The trap trees commonly used against Ips typographus turned out to be very effective also in the control of I. amitinus.