Ökologische Bedingungen für Primärbefall durch ‚Xylosandrus germanus’

Abstract

Zusammenfassung 1961 folgte eine Wiederholung des Befalls von 1959 in einem Roteichen‐jungbestand, bevorzugt befallen wurden spätaustreibende Jungeichen, meist stärkere Stämmchen. 1962 gab es nur schwachen Stockbefall in der Nähe der Roteichen, eingeengt durch ungünstiges Wetter. 1963 wurde eine größere Fläche mit frischem Einschlag von Altbuchen stärker angeflogen. Die ökologischen Bedingungen waren genügend breit variiert, und es wurde festgestellt, daß der direkte Anflug von dem Grad der Beschattung und dem Gesundheitszustand des Stockes abhängt. Bevorzugt wird für den Anflug der kürzeste Weg, aber auch Entfernungen über 200–300 m werden mit entsprechender Verzögerung überwunden. Im Stock selbst wird das gesunde und feuchte Holz bevorzugt, Bedingungen entsprechend, die einem pilzzüchtenden Käfer gestellt sind. Xyleborinus saxeseni ist allgemein später und in wenigen Exemplaren 1963 erschienen. Wenn Gefahr für entsprechend disponierte Laubholzjungkulturen manmangels frischer Stöcke besteht, muß eine rechtzeitige Stockbegiftung kurz vor Ausflug durchgeführt werden. Stehende Altbäume (Eiche, Buche, Birke) geschnittene, liegende Stämme und Wipfelholz, Äste (am Windbruch kontrolliert) ließen keinen Befall erkennen. Summary In 1961 an attack recurred in a stand of young red oak trees which was already noticed in 1959. Particularly late‐sprouting young trees were infested, in most cases thicker young stems. In 1962 there was only a slight attack to stumps in the vicinity of red oaks due to unfavourable weather conditions. In 1963 a larger area with newly‐felled old oaks became strongly infested. The ecological conditions varied broadly, and it was found that the direct flight depends on the degree of shading and the physical conditions of the stump. For the flight to the host the shortest way is preferred but even distances of 200–300 m can be overcome, although not without delay. In the stump preference is given to the healthy and moist wood, in accordance with the conditions given to a fungus growing beetle. In 1963 Xyleborinus saxeseni generally appeared later and with a few individuals only. If danger exists for a predisposed stand of young deciduous trees due to lack of fresh stumps chemical treatment of the stumps is to be recommended before the flight begins.

Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees

“…crassiusculus utilize healthy naïve trees in non-native habitats, especially in the absence of weakened ones, is also poorly understood and unsubstantiated. Attacks have been suspected to occur on apparently-healthy trees [ 10 , 21 , 46 – 48 ], but such trees may actually have been inapparently-stressed at the time of attack [ 9 ]. Comparing colonization success on flood-stressed and non-flooded trees could thereby provide crucial insight into host utilization within non-native habitats and aid in characterizing factors contributing to the invasiveness of X .…”

Inbreeding and selection on sex ratio in the bark beetle Xylosandrus germanus

“…Third, X . germanus has only recently been introduced into Europe from East Asia [ 47 , 48 ]. This means it is possible that any changes in the breeding system and patterns of dispersal associated with this introduction are not yet in equilibrium with the observed sex ratio pattern.…”

Eficacitatea a două insecticide în prevenirea atacului de Xylosandrus germanus (Coleoptera: Curculionidae, Scolytinae), în condiții de teren

“…Chiar dacă până acum în România nu a fost semnalat decât un singur caz de atac provocat de această specie, într-o livadă din partea de vest a țării (Olenici et al, 2022), pe baza informațiilor din literatură (Heidenreich 1964, Maksymov 1987, Graf și Manser 2000, Zach et al 2001, Böll et al 2005, Agnello et al 2015, 2017, Ranger et al 2016, Dutto et al 2018, Galko et al 2019, Hauptman et al 2019, Ruzzier et al 2021) ea ar trebui să fie considerată un potențial dăunător în păduri, livezi și podgorii (Olenici et al, 2015).…”