Mortality in young families of Eucalyptus regnans due to Phytophthora cinnamomi, up to five years after planting.  J. A. Harris, F. Y. Kassaby and I. W. Smith.  November 1984.  11 pp. (unpubl.)

SUMMARY

Mortality caused by Phytophthora cinnamomi Rands (phytophthora root rot) was studied over a period of three years, among saplings of Eucalyptus regnans F. Muell (mountain ash) raised from seed from individual trees of above-average form and vigour, in a seed orchard near Mt Disappointment, north of Melbourne. Approximately 2820, 4120 and 4930 seedlings were planted in 1977, 1979 and 1981 respectively, and their origin and characteristics were recorded; these represented the progeny of 40 trees from four separate forest areas.

Phytophthora cinnamomi was isolated in July 1979 from lesions under bark of the larger roots and stem collar of saplings planted in 1977 and proof of pathogenicity was obtained. This was the first record of this type of injury on a eucalypt.

The study showed that mortality was recurrent, with similar mortality in each year studied. There was significant variation in tolerance to root and stem infection among families of E. regnans, and between provenances; mortality being significantly higher in families of South Gippsland seed origin than in those from the Toolangi forest area. Also, planting the seedlings in ripped lines appeared to have created an environment favourable to disease development, namely, increased moisture and inoculum potential around roots.

Also published:

Harris, J.A., Kassaby, F.Y. and Smith, I.W. (1985)  Variation in mortality in families of Eucalyptus regnans caused by Phytophthora cinnamomi up to five years after planting.  Aust. For. Res. 15 (1): 57-65.