Treatments influencing susceptibility of Nothofaguscunninghamii to the ambrosia beetle Platypussubgranosus in Australia

Abstract

Of treatments imposed to stress Nothofaguscunninghamii (Hook.) Oerst. trees, only infection by the vascular stain pathogen Chalaraaustralis Walker & Kile caused intensive and sustained attack by the ambrosia beetle Platypussubgranosus Schedl. Other treatments that damaged stems or led to tree death resulted in some P. subgranosus attack soon after treatment or at death, but effects were generally small compared with those of C. australis infection. The number of tunnels initiated on stems by the beetle was correlated with the number of beetles caught on adhesive traps on the same trees. Platypussubgranosus attack on inoculated trees was nonrandom and associated with the presence of C. australis in the underlying wood. Injection of trees with isobutyl acetate, the major volatile metabolite produced by the fungus invitro, did not increase their attractiveness to P. subgranosus. Wounded Atherospermamoschatum Labill. were also attacked by P. subgranosus.