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Host resistance in defoliated pine: effects of single and mass inoculations using bark beetle‐associated blue‐stain fungi
Author(s) -
Långström Bo,
Solheim Halvor,
Hellqvist Claes,
Krokene Paal
Publication year - 2001
Publication title -
agricultural and forest entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.755
H-Index - 55
eISSN - 1461-9563
pISSN - 1461-9555
DOI - 10.1046/j.1461-9555.2001.00109.x
Subject(s) - biology , inoculation , scots pine , host (biology) , bark beetle , botany , bark (sound) , horticulture , host resistance , curculionidae , pinus <genus> , ecology , immunology
Abstract 1 In 1996, 7000 ha of pine forests were defoliated by the pine looper Bupalus piniaria in south‐western Sweden. 2 The susceptibility of trees of different defoliation classes (0, 30, 60, 90 and 100% defoliation) to beetle‐vectored blue‐stain fungi was tested in inoculation experiments. Forty and 120‐year‐old Scots pine trees were inoculated with ‘single’, i.e. a few inoculations of Leptographium wingfieldii and Ophiostoma minus , two blue‐stain fungi associated with the pine shoot beetle Tomicus piniperda . The young trees were also ‘mass’ inoculated with L. wingfieldii at a density of 400 inoculation points per m 2 over a 60 cm stem belt. 3 Host tree symptoms indicated that only trees with 90–100% defoliation were susceptible to the mass inoculation. 4 Single inoculations did not result in any consistent differences in fungal performance between trees of different defoliation classes, regardless of inoculated species or tree age class. 5 Leptographium wingfieldii produced larger reaction zones than O. minus , and both species produced larger lesions in old than in young trees. 6 As beetle‐induced tree mortality in the study area occurred only in totally defoliated stands, mass inoculations seem to mimic beetle‐attacks fairly well, and thus seem to be a useful tool for assessing host resistance. 7 As even severely defoliated pine trees were quite resistant, host defence reactions in Scots pine seem to be less dependent on carbon allocation than predicted by carbon‐based defence hypotheses.