Sooty blotch on Douglas fir (Pseudotsuga menziesii) was reported by Gilmour (1959a) to be present only in plantations within a 60-mile radius of Taupo. He reported that it appeared not to be causing any damage to the trees.

Type: Foliicolous Fungi; Description: Ascomata perithecial, in rows corresponding to rows of stomata, superficial, globose, black, 50–100 μm in diameter, each attached to a tiny peg of tissue inserted into a stoma on the underside of a needle and attached by this to fine, olivaceous hyphae within the needle. Asci clavate, 30–40 × 8–14 μm. Ascospores slightly clavate, 1-septate, 10–15 × 3–5 μm, smooth, hyaline.

Distribution: Northland, Auckland, Waikato, Bay of Plenty, Taranaki, Taupo, Wanganui, Wellington, Gisborne, Hawkes Bay, Wairarapa, Nelson, Buller, Westland, Marlborough, Kaikoura, North Canterbury, Mid Canterbury, South Canterbury, Central Otago, Dunedin, Southland.; 1st Record: Gilmour (1959).

Significance: The cause of ‘Swiss needle-cast’, a major disease of Douglas fir in New Zealand. It was first recorded in 1959 when present only in a limited area around Taupo. Its progress was carefully observed and it took about 30 years for the fungus to spread throughout the country (Hood et al. 1990). Analysis of data from 1500 permanent sample plots showed that the reduction in volume increment following the appearance of the disease was: Central North Island 21%; Nelson 9%; Canterbury 20%; Otago 23% (Knowles et al. 2001). Hood (1982) showed that levels of infection in provenances of Pseudotsuga menziesii originating west of the Coast-Cascade Mountains in British Columbia, Washington and Oregon were significantly lower than in provenances originating in the area between the Coast Range and the eastern mountains. Future planting of selected resistant trees and provenances is expected to reduce the effect of the disease.; Host(s): Pseudotsuga macrocarpa, P. menziesii.