Swiss needle cast of Douglas Fir in Victoria 1. Distribution, rate of spread and effects on tree growth.  R.J. McKimm and H.T.L. Stewart and.  June 1975.  10 pp.  (unpubl.)

SUMMARY

In June 1974, Phaeocryptopus gaeumannii, the fungus responsible for Swiss needle cast disease of Douglas-fir was identified on the needles of unthinned Douglass-fir plantings at Narbethong, Victoria. The stands in which the fungus was found were suffering from moderate to severe needle cast defoliation.

The infestation was regarded as serious and investigations to determine the distribution, effect of the disease on growth, and rate of spread were commenced. The results of this work showed that the fungus was confined to the Narbethong plantation, basal-area growth at Narbethong was substantially less than for all other localities, and dramatic decreases in basal-area growth occur in many unthinned plantations of Douglas-fir in Victoria at around age 25-30 years. Rate of spread and the time of infection of the plantation at Narbethong could not be determined from stem analysis.

Further study is needed to determine the effects of thinning and fertilizing on the growth and health of Douglas-fir at Narbethong before the potential of Swiss needle cast disease to damage this species in Victoria can be indicated.