The needle-infecting fungus Phaeocryptopus gaeumannii (Rohde) Petrak spread to stands of Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] in most parts of New Zealand following its first detection in the central North Island in 1959. At Hanmer Forest in the South Island, the percentage of infected needles rose more rapidly in a provenance from northern inland California than in one from Kaingaroa Forest in the North Island. Increase in infection was accompanied bv a significant decrease in the proportion of needles retained on shoots of certain age classes, the reduction in the Californian seedlot being greater than in that from Kaingaroa. More older foliage was retained in the Kaingaroa provenance at Hanmer Forest, when infection averaged under 30 %, than at two other locations where mean infection exceeded 90%. It is suggested tnat heavily infected production stands of Douglas fir suffer some premature casting of older needles, even when crowns appear healthy.

No abstract