L. Swart

Fungal endophytes of Proteaceae, with particular emphasis on Botryosphaeria proteae

Fungal endophytes occurring in leaves and stems of three species of Proteaceae,Protea cynaroides, Leucospermum cordifolium andLeucadendron salignum×laureolum were investigated on farms in three locations in the Western Cape province of South Africa. The aims of this study were to determine ifBotryosphaeria proteae, a fungus that has been recorded from leaf spots ofProtea spp., was mostly restricted to leaf tissue, and whether it could occur as an endophyte in different members of Proteaceae. In this studyB. proteae was routinely isolated inProtea andLeucospermum, although it was not a dominant taxon and did not occur inLeucadendron. Botryosphaeria proteae occurred mostly in leaves, rather than stems, suggesting that it is not important as a stem canker pathogen.

Fungi occurring on Proteaceae. I.

The present study has led to the description of several new fungi occurring on leaves of Protea L., Leucospermum R.Br., Telopea R.Br. and Brabejum L. collected from South Africa, Australia or New Zealand, Cladophialophora proteae L. Viljoen & Crous, Coniothyrium nitidae Crous & S. Denman, Coniothyrium proteae Crous & S. Denman, Coniothyrium leucospermi Crous & S. Denman, Harknessia leucospermi Crous & L. Vilioen, and Septoria protearum L. Viljoen & Crous spp. nov, are described from Protea and Leucospermum in South Africa, while Phyllosticta owaniana G. Winter is redescribed from leaves of Brabejum stellatifolium L. Furthermore, Mycosphaerella telopeae M. Palm & Crous sp. nov. is described from leaves of Telopea collected in New Zealand, while Phyllosticta telopeae H.Y. Yip, which also occurs on this host, is described in culture from Australian material.

First record of Fusarium oxysporum f. sp. basilici occurring on sweet basil in South Africa

This is the first record of Fusarium oxysporum f. sp. basilici causing wilt and crown rot of sweet basil plants in the Western Cape province of South Africa. The identification of the pathogen was confirmed with a PCR assay using the Fusarium oxysporum f. sp. basilici specific primer pair, Bik 1 + Bik 2.

Fusarium wilt: A new disease of cultivated Protea in Southern Africa

A newly recorded disease of cultivated Protea, Fusarium wilt, is described and shown to be caused by Fusarium oxysporum. The disease occurs on mature plants (2-year-old) of P aristata x repens cv. Venus, P cornpacta x susannae cv. Pink Ice, P. cynaroides, P. eximia x susannae cv. Cardinal, P. eximia x susannae cv. Sylvia, P. magnijka x susannae cv. Susara and P. repens cv. Sneyd in the summer rainfall areas of the North-Western province of South Africa and in Zimbabwe. Disease symptoms first become visible as necrotic leaves. Subsequently, a dark lesion develops from the roots along the stem, usually visible only on one side of the stem. Occasionally the lesion develops in the upper part of the stem. The vascular tissue is discoloured leading to branch die-back and plant death. F. oxysporum was readily isolated from the roots, crown and vascular tissues of infected plants. Koch’s postulates were proved on six Protea cultivars. Disease symptoms similar to those observed in the field developed 6 weeks after inoculation on all cultivars. The fungus was re-isolated from the roots; crown and vascular tissues of inoculated plants. This is the first record of Fusarium wilt on Protea plants.