Two small adjacent sub-antarctic islands having many features in common, but with markedly different modified vegetation, are considered in the light of historical records and field work in 1954 and 1966. When the Auckland Islands were discovered in 1806 Enderby and Rose Islands probably had the same general vegetative pattern with southern rata (Metrosideros umbellata) forest and scrub on southeastern parts giving way to Poa Iitorosa tussock on the more exposed northwestern parts. MUl.h of the present vegetation on the two islands has been induced by fire and introduced mammals, the legacy of a period of shipwrecks and attempts at settlement and farming. Large areas of short sward and of dead trees now occur. Tussock grassland has practically disappeared from Enderby, but still covers much of Rose Island. Nowadays, mice (Mus mllscll/lls) , rabbits (Oryctolagus cllniclIllls), and feral cattle (Bos taurus) occur in Enderby, and rabbits alone on Rose Island. Their numbers, distribution, and interrelations with the vegetation are discussed. On Rose Island, where tussock and scrub are increasing, rabbits have markedly declined since 1954, whereas on Enderby an apparent balance has been reached between the introduced mammals and the much modified vegetation. The history and present status of bird and seal populations are described. After early exploitation and virtual extermination, southern royal albatrosses (Diomedea e. epomophora) and seals (Arctocephalus forsteri and Neophoca hooker;) are now increasing. On Enderby there are breeding sea-lions, many native bird species, cattle, and rabbits all in an interacting relationship which is not obviously detrimental to any of them or to the present vegetation. The Auckland Islands have been reserves for the preservation of flora and fauna since 1934 and are potentially valuable for studying interactions between native and introduced species. Existing environmental trends on Enderby and Rose Islands have positive conservation and scientific values and any manipUlation. such as the control of cattle and rabbits, now seems undesirable.

In Victoria cucumber mosaic virus (CMV) has been shown to be the cause of the woodiness disease of Passifloua edulis. This virus causes a slow decline of infected P. edulis seedlings, and a more rapid decline of vines grafted onto P. caerulea rootstocks. In Queensland a similar disease of passion fruit also occurs. The Queensland disease was shown to be caused by a virus which differed markedly from CMV, This virus, which is designated herein as passion fruit woodiness virus (PWV), has flexuous rod-shaped particles about 670 mµ in length. PWV was shown to be stylet-borne by the aphid Myzus persicae and to be transmitted to Phaseolus vulgaris and Sesbania exaltata by sap inoculation. The physical properties of PWV were determined, and two isolates of the virus were purified and antisera prepared against them.

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SummaryThe host range, symptomatology, serology, and electron microscopy of one isolate of bean yellow mosaic virus (BYMV) and of three isolates of pea mosaic virus (PMV1, PMV2, and PMV3) were compared. All had similar host ranges, but could be differentiated by symptomatology. BYMV, P.~VI, and PMV2 were closely related serologically.The normal particle length of PMVI was consistently in the range 787-800 mfL, whereas with BYMV it varied according to the host plant. From legumes it was within the range 742-756 mfL and from Chenopodium amaranticolor 794-800 mI" PMV2 and PMV3 had particles of similar length to PMVl.Morphological differences were observed between some particles of BYMV and PMVI from leguminous hosts, but not from C. amaranticolor. The pitfalls of using particle length measurements as a criterion of strain relationship are discussed. It is concluded that all the isolates should be regarded as strains of BYMV.

Evidence is presented to show that many grapevines showing leaf symptoms which, particularly when intense, cannot be distinguished from those caused by strains of grapevine fanleaf virus (GFV) or tomato ringspot virus (TRSV) are infected with a previously undescribed disease for which the name grapevine yellow speckle (GYS) is proposed. The causal agent of the disease has not been isolated, but it is graft-transmissible from infected to healthy grapevines. It has not been transmitted by sap inoculation to herbaceous plants. The disease has been detected in some grapevine cultivars grown in Australia for many years, and also in several other cultivars and rootstocks imported from California over the past 10 years. There is no evidence of natural spread or of seed transmission. Attempts to eliminate GYS from plants by heat therapy and propagation of tip cuttings have been unsuccessful. Mataro and LN33, the best indicators for GYS at present, are not entirely satisfactory and there is a need to find an indicator which will detect GYS in a wide range of environments. The disease has not been previously detected, probably because of its similarity to GFV and TRSV and its peculiarity in expressing symptoms only in some environments.