The role of sulphur compounds for breeding success of Ips typographus L. (Col., Scolytidae) on Norway Spruce (Picea abies [L.] Karst.) |
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Authors: | J Mattanovich M Ehrenhöfer C Schafellner M Tausz & E Führer |
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Institution: | Institute of Forest Entomology, Forest Pathology and Forest Protection, Boku, Vienna, Austria;Institute of Plant Physiology, Karl-Franzens University Graz, Schubertstraße 51, Graz, Austria |
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Abstract: | Bark beetles, especially Ips typographus L. represent a severe biotic threat for spruce ( Picea abies L.] Karst.) at low altitudes in Europe. We compared sulphur (total S, SO42−, glutathione, cysteine, methionine), nitrogen (total N, NO3−, total protein, free amino acids), carbon, total phosphorus and PO43−, tree vigour index (TVI) and water content of the phloem after felling, and their dependent changes (tdc) with the breeding success of I. typographus . Twenty trees were classified according to age (34/90 years) and crown density (high/intermediate/low). Water content was higher in young trees than in old trees, higher in the crown than at breast height, and decreased significantly within the 8-week study period. In old trees, breeding success, length of mother galleries and SO42− were significantly higher, while total protein, NO3− and water content were significantly lower than in young trees. Trees with intermediate crown density provided the best breeding success for I. typographus and had significantly higher arginine content and C/N ratio as well as low amounts of phosphate and glutamine. During the period of bark beetle breeding, total sulphur, glutathione, protein, NO3−, aspartate, glutamine, glutamate, arginine and γ-aminobutyrate decreased significantly. The results support previous investigations that I. typographus develops best in physiologically weakened trees. |
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