Cambioxylophagous fauna developing on logging residues of blue spruce (Picea pungens Engelmann)

Abstract

Cutting down 20- to 30-years-old trees of blue spruce (Picea pungens Engelm.) (October, May) and cross-cutting them to sections of different volume (0.5–75 dm3) under conditions of half-shade × open area resulted in a potential food offer for cambiophages. Ips amitinus (Eichh.) and Pityogenes chalcographus (L.) reached the higher frequency of occurrence on sections placed in the open area than in half-shade and on stems felled in the autumn season than in the spring season. Dryocoetes autographus (Ratz.) was markedly profiled on sections in half-shade with the gradual desiccation of phloem. P. chalcographus preferring open areas occurred on branches being accompanied by Cryphalus abietis (Ratz.), which attacked branches located in half-shade. On stems of sections from both autumn and spring felling, one generation of I. amitinus developed, however, on autumn sections, the 2<sup>nd</sup> generation developed unsuccessfully on the original nutritive material. P. chalcographus completed the development of one generation on stems and branches from autumn felling. On the spring material, the invasion was delayed and a part of wintering larvae did not complete their development. Logging residues of P. pungens were available for the development of I. amitinus and P. chalcographus during one growing season only.