Effect of Scleroderma spore density and age on mycorrhiza formation and growth of containerized Eucalyptus globulus and E-Urophylla seedlings

Greenhouse trials with containerized Eucalyptus globulus and E. urophylla seedlings were made to determine effective inoculum spore densities (Scleroderma cepa from temperate Australia, and S. citrinum from sub-tropical China) and spore storage conditions (fresh spores or spores stored for 5 years at room temperature or at 4 degrees C; S. albidum, S. areolatum and S. cepa from Western Australia). Inoculation with 10(6) or 10(8) spores/seedling increased eucalypt growth by up to 46% in height and 42% in dry weight compared to non-inoculated seedlings at 12 weeks after inoculation. Mycorrhizal formation was poor at 10(2) spores/seeding. Spores stored at 4 degrees C for 5 years were as effective in forming mycorrhizas as freshly collected spores when a standard density of 10(6) spores/seedling was applied. It is recommended that spore densities >= 10(4) be used for inoculation of containerised eucalypts and that spores be stored at 4 degrees C until use.