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Esterhuizen L.L.,University of Johannesburg | Mabasa K.G.,ARC Vegetable and Ornamental Plant Institute | Mabasa K.G.,University of Witwatersrand | Van Heerden S.W.,Sakata Vegenetics RSA Pty Ltd | And 5 more authors.
Journal of Applied Entomology | Year: 2013

The whitefly Bemisia tabaci cryptic species complex contains some important agricultural pest and virus vectors. Members of the complex have become serious pests in South Africa (SA) because of their feeding habit and their ability to transmit begomovirus species. Despite their economic importance, studies on the biology and distribution of B. tabaci in SA are limited. To this end, a survey was made to investigate the diversity and distribution of B. tabaci cryptic species in eight geographical locations (provinces) in SA, between 2002 and 2009, using the mitochondrial cytochrome oxidase I (mtCOI) sequences. Phylogenetic analysis revealed the presence of members from two endemic sub-Saharan Africa (SSAF) subclades coexisting with two introduced putative species. The SSAF-1 subclade includes cassava host-adapted B. tabaci populations, whereas the whiteflies collected from cassava and non-cassava hosts formed a distinct subclade, referred to as SSAF-5, and represent a new subclade among previously recognized southern Africa clades. Two introduced cryptic species, belonging to the Mediterranean and Middle East-Asia minor 1 clades, were identified and include the B and Q types. The B type showed the widest distribution, being present in five of the eight provinces explored in SA, infesting several host plants and predominating over the indigenous haplotypes. This is the first report of the occurrence of the exotic Q type in SA alongside the more widely distributed B type. Furthermore, mtCOI PCR-RFLP was developed for the SA context to allow rapid discrimination between the B, Q and SSAF putative species. The capacity to manage pests and disease effectively relies on knowledge of the identity of the agents causing the damage. Therefore, this study contributes to the understanding of South African B. tabaci species diversity, information needed for the development of knowledge-based disease management practices. © 2012 Blackwell Verlag, GmbH.


Jacobs A.,Plant Protection Institute | Van Heerden S.W.,Sakata Vegenetics RSA Pty Ltd
Australasian Plant Disease Notes | Year: 2012

In 2007, vascular browning, root and crown rot were observed on tomato plants in the East London area, South Africa. Fusarium oxysporum f. sp. radicis-lycopersici proved to be a causal agent of the disease by means of morphological and DNA based characterization as well as pathogenicity trials. This is the first report of Fusarium oxysporum f. sp. radicis-lycopersici on tomatoes in South Africa. © 2012 Australasian Plant Pathology Society Inc.


Jacobs A.,Plant Protection Institute | Govender R.,Sakata Vegenetics RSA Pty Ltd. | Van Heerden S.W.,Sakata Vegenetics RSA Pty Ltd.
Australasian Plant Disease Notes | Year: 2013

In 2010, tomato plants exhibiting symptoms of wilting, hollow stems and vascular discoloration from the Musina district, Limpopo Province, South Africa were reported. Fusarium oxysporum f. sp.lycopersici race 3 proved to be a causal agent of the disease by means of morphological and DNA based characterization accompanied by pathogenicity trials. This is the first report of Fusarium oxysporum f. sp. lycopersici race 3 on tomato in South Africa. © 2013 Australasian Plant Pathology Society Inc.

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