Publication Date:
2024-05-03
Description:
Trunk disease fungal pathogens reduce olive production globally by causing cankers, dieback, and other
decline-related symptoms on olive trees. Very few fungi have been reported in association with olive dieback and
decline in South Africa. Many of the fungal species reported from symptomatic olive trees in other countries have
broad host ranges and are known to occur on other woody host plants in the Western Cape province, the main olive
production region of South Africa. This survey investigated the diversity of fungi and symptoms associated with
olive dieback and decline in South Africa. Isolations were made from internal wood symptoms of 145 European and
42 wild olive trees sampled in 10 and 9 districts, respectively. A total of 99 taxa were identified among 440 fungal
isolates using combinations of morphological and molecular techniques. A new species of Pseudophaeomoniella,
P. globosa, had the highest incidence, being recovered from 42.8 % of European and 54.8 % of wild olive samples.
This species was recovered from 9 of the 10 districts where European olive trees were sampled and from all districts
where wild olive trees were sampled. Members of the Phaeomoniellales (mainly P. globosa) were the most prevalent
fungi in five of the seven symptom types considered, the only exceptions being twig dieback, where members of the
Botryosphaeriaceae were more common, and soft/white rot where only Basidiomycota were recovered. Several of
the species identified are known as pathogens of olives or other woody crops either in South Africa or elsewhere
in the world, including species of Neofusicoccum, Phaeoacremonium, and Pleurostoma richardsiae. However, 81
of the 99 taxa identified have not previously been recorded on olive trees and have unknown interactions with this
host. These taxa include one new genus and several putative new species, of which four are formally described as
Celerioriella umnquma sp. nov., Pseudophaeomoniella globosa sp. nov., Vredendaliella oleae gen. & sp. nov., and
Xenocylindrosporium margaritarum sp. nov.
Keywords:
Ecology
;
Evolution
;
Behavior and Systematics
;
Celerioriella
;
five new taxa
;
Olea europaea subsp. cuspidata
;
Olea europaea subsp. europaea
;
phylogenetics
;
Pseudophaeomoniella
;
taxonomy
;
Vredendaliella
;
Xenocylindrosporium
Repository Name:
National Museum of Natural History, Netherlands
Type:
info:eu-repo/semantics/article
Format:
application/pdf
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