Potential insect vectors and alternative host plants of pathogens associated with citrus greening in citrus (Citrus spp., Rutaceae) and grapevine yellows (GY) in grapevine (Vitis vinifera, Vitaceae) were surveyed in the fynbos and succulent karoo biomes in the Western Cape in South Africa. The insect-transmitted diseases are associated with the presence of bacterial pathogens (‘Candidatus Phytoplasma’ and ‘Candidatus Liberibacter’) that threaten the production and international trade of these crops. Despite previous efforts, the knowledge concerning potential insect vectors and the host range in indigenous host plants is limited. Three surveys were carried out in September (spring) in 2017, and January (summer) and August (winter) in 2018 in the natural vegetation at nine sites. Insects were collected with vacuum sampling from 20 randomly selected plant samples per species at the specific sites. Branches with leaves from the same plant species were collected, and both insects and plant samples were tested for the presence of phytoplasmas and liberibacters by quantitative polymerase chain reaction (real time PCR) or nested PCR and sequencing. Alternative host plants from 989 samples representing 42 species belonging to 19 families were analysed. None of the 42 plant species tested positive for ‘Ca. Liberibacter africanus’, the agent of citrus greening in South Africa. Aster yellows phytoplasma (16SrI-B), which has been reported infecting grapevine in three regions in the Western Cape, was identified in a plant species belonging to the Aizoaceae. Other phytoplasmas were detected from species belonging to the Brassicaceae, Montiniaceae and Proteaceae and in a few insect specimens belonging to the Auchenorrhyncha (Hemiptera). The data generated will be used for biological and epidemiological studies and the development of management strategies. This work was carried out under the framework of the European Union’s Horizon 2020 research and innovation programme TROPICSAFE under grant agreement No. 727459.
Potential insect vectors and alternative host plants of insect-transmitted liberibacter and phytoplasmas in the fynbos biome in the Western Cape / Krüger K, J. van Wyk, M. Stiller, G. Pietersen, R.J. van Rensburg, R. Roberts, Ge. Pietersen, E. Satta, A. Bertaccini. - STAMPA. - (2019), pp. 69-69. (Intervento presentato al convegno 21st Congress of the Entomological Society of Southern Africa - ESSA 2019 tenutosi a Umhlanga nel 8–11 July).
Potential insect vectors and alternative host plants of insect-transmitted liberibacter and phytoplasmas in the fynbos biome in the Western Cape
E. Satta;A. Bertaccini
2019
Abstract
Potential insect vectors and alternative host plants of pathogens associated with citrus greening in citrus (Citrus spp., Rutaceae) and grapevine yellows (GY) in grapevine (Vitis vinifera, Vitaceae) were surveyed in the fynbos and succulent karoo biomes in the Western Cape in South Africa. The insect-transmitted diseases are associated with the presence of bacterial pathogens (‘Candidatus Phytoplasma’ and ‘Candidatus Liberibacter’) that threaten the production and international trade of these crops. Despite previous efforts, the knowledge concerning potential insect vectors and the host range in indigenous host plants is limited. Three surveys were carried out in September (spring) in 2017, and January (summer) and August (winter) in 2018 in the natural vegetation at nine sites. Insects were collected with vacuum sampling from 20 randomly selected plant samples per species at the specific sites. Branches with leaves from the same plant species were collected, and both insects and plant samples were tested for the presence of phytoplasmas and liberibacters by quantitative polymerase chain reaction (real time PCR) or nested PCR and sequencing. Alternative host plants from 989 samples representing 42 species belonging to 19 families were analysed. None of the 42 plant species tested positive for ‘Ca. Liberibacter africanus’, the agent of citrus greening in South Africa. Aster yellows phytoplasma (16SrI-B), which has been reported infecting grapevine in three regions in the Western Cape, was identified in a plant species belonging to the Aizoaceae. Other phytoplasmas were detected from species belonging to the Brassicaceae, Montiniaceae and Proteaceae and in a few insect specimens belonging to the Auchenorrhyncha (Hemiptera). The data generated will be used for biological and epidemiological studies and the development of management strategies. This work was carried out under the framework of the European Union’s Horizon 2020 research and innovation programme TROPICSAFE under grant agreement No. 727459.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
