Recovery of Potentially Pathogenic Phytophthora and Pythium Spp. From Native Vegetation in Australia

Abstract

Soil and plant root samples from a variety of native forest habitats throughout Australia were examined for potentially pathogenic Pythium and Phytophthora spp. by lupin baiting.Those It is suggested that disease of native plant species normally attributed to Ph. cinnamomi could be caused by other Pythium and Phytophthora species, acting singly or alone, with or without Ph. cinnamomi.

Non-Mendelian Inheritance Revealed in a Genetic Analysis of Sexual Progeny of Phytophthora cinnamomi with Microsatellite Markers

“…This analysis occurred 4 years after the original mating during which time the progeny had been subcultured four times on cornmeal agar. Zoospore production was modified from a method of Pratt and Heather (1973). We grew isolates on V8 agar (Hü berli et al, 1997) for 5-7 days and then cut 1-cm 2 sections of mycelium on agar from the growing edge and placed them in sterile 9-cm petri dishes.…”

Separation of Two Ecotypes of Phytophthora Drechsleri Tucker Occurring in Australian Native Forests

“…Both also possessed hyphal swellings of the type described by previous authors for P. drechsleri, although these were more common in the southern than in the northern ecotype. Isolates of both ecotypes produced a few apparently homothallic oospores on inoculum plugs and oogonia, oospores, and amphigynous antheridia were similar in size, shape, and colour in each ecotype (Pratt and Heather 1973). In addition, the parallelism of the growth response curves in the presence of copper sulphate, pyronin G, and malachite green is considered to support strongly the claim that the two groups of organisms are ecotypes of a single species, P. drechsleri.…”

“…This paper, together with that of Pratt and Heather (1973), presents the first demonstration of sub specific groups based on physiological rather than pathogenic criteria. The salient characteristics of the two ecotypes are summarized in Table 8.…”

“…1970). Pratt and Heather (1973) provided the first record of an association of this fungus with disease of native vegetation and reported that P. drechsleri occurred widely in soils from native forest areas, where it was frequently associated with disease of a variety of tree and understorey species. The 55 isolates examined by them were morphologically similar, but could be separated into two groups according to the ability of isolates to produce oospores in the presence of other species of fungi.…”

A Synopsis of Important Pests and Diseases in Australian Forests and Forest Nurseries

“…This is caused primarily by P. cinnamomi, probably the most destructive root pathogen in Australia. Some workers (Pratt and Heather 1973a, 1973b, Pratt et al 1974 have suggested that various oomycetous fungi, such as Pythium spp., and other Pytophthora spp., may be involved in the disease etiology of this dieback. However, Marks and Kassaby ( 197 4,and unpublished data) have tested the pathogenicity of six species of Pythium and ten species of Phytophthora, and found that only P. cinnamomi was capable of killing 4-month-old eucalypts.…”