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Coconut lethal yellowing phytoplasma disease in Mozambique

diversity, host range, and the impact of farming practices on disease incidence

Bila, João (2016). Coconut lethal yellowing phytoplasma disease in Mozambique. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2016:33
ISBN 978-91-576-8568-1
eISBN 978-91-576-8569-8
[Doctoral thesis]

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The coconut palm (Cocos nucifera) is a major cash crop that is widely grown in coastal tropical regions of the world, including Mozambique. Outbreaks of coconut lethal yellowing disease (CLYD) are threatening the industry and the livelihood of a large part of the Mozambican population. The aim of this thesis was to study different epidemiological aspects of CLYD in Mozambique. Phylogenetic analyses of the 16S and secA genes were performed on plant and insect samples collected from different agro-ecological zones of Mozambique and Tanzania. A socio-economic survey was conducted to assess the effect of farming practices on CLYD incidence in Mozambique. The results revealed a high diversity of phytoplasma species associated with CLYD in Mozambique, namely: ‘Candidatus Phytoplasma palmicola’ 16SrXXII-A, Tanzanian lethal disease (LD) phytoplasma 16SrIV-C and a novel strain closely related to ‘Ca. Phytoplasma pini’ 16SrXXI-A, which was found in a mixed infection with ‘Ca. Phytoplasma palmicola’. Population genetics analyses confirmed the observed high phytoplasma diversity associated with CLYD in Mozambique. The studies also revealed that ‘Ca. Phytoplasma palmicola’ and Tanzanian LD phytoplasma occur in both Mozambique and Tanzania. A search for alternate hosts revealed that the palm species Elaeis guineensis and Borassus aethiopum are alternate hosts of CLYD phytoplasma in Mozambique. Previously, the potential insect vector of CLYD in Mozambique was thought to be the Platacantha lutea bug; however, our findings suggest that the potential alternate vector is the planthopper Diostrombus mkurangai. Finally, the results revealed that farm age, the presence of other palm species on the coconut farm, type of coconut variety grown, root cut practices and intercropping all had a significant (P<0.05) effect on CLYD incidence. This research study has increased our knowledge of CLYD epidemiology in Mozambique, which should help with the development of a more sustainable CLYD management strategy.

Authors/Creators:Bila, João
Title:Coconut lethal yellowing phytoplasma disease in Mozambique
Subtitle:diversity, host range, and the impact of farming practices on disease incidence
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :May 2016
Depositing date:18 May 2016
Number of Pages:62
IBila J, Mondjana A, Samils B, and Högberg N. 2015b. High diversity, expanding populations and purifying selection in phytoplasmas causing coconut lethal yellowing in Mozambique. Plant Pathology 64:597–604.
IIBila J, Högberg N, Mondjana A, and Samils B. 2015a. African fan palm (Borassus aethiopum) and oil palm (Elaeis guineensis) are alternate hosts of coconut lethal yellowing phytoplasma in Mozambique. African Journal of Biotechnology, 14(52): 3359–3367.
IIIBila J, Mondjana A, Samils B, Högberg N, Wilson MR, and Santos L. 2016. First report of ‘Candidatus Phytoplasma palmicola’ detection in the planthopper Diostrombus mkurangai in Mozambique (Manuscript submitted).
IVBila J, Persson I, Högberg N, Mondjana A, Manuel L, Tostão E, Johansson N, Söderlind J, and Santos L. 2016. Effect of farming practices and farm history on the incidence of coconut lethal yellowing in Mozambique. African Crop Science Journal, 24(2) (In press).
Place of Publication:Uppsala
Publisher:Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8568-1
ISBN for electronic version:978-91-576-8569-8
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F30 Plant genetics and breeding
H Protection of plants and stored products > H20 Plant diseases
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Evolutionary Biology
(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 208 Environmental Biotechnology > Diagnostic Biotechnology
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Agricultural Science
Agrovoc terms:cocos nucifera, plant diseases, phytoplasmas, pathogens, phylogeny, host plants, host pathogen relations, disease transmission, alternative hosts, borassus aethiopum, elaeis guineensis, oryctes, fulgoroidea, vectors, cropping systems, mozambique
Keywords:coconut lethal yellowing phytoplasma, ‘Candidatus Phytoplasma palmicola’, coconut palm, Mozambique, alternate host, insect vector, farming practices, phytoplasma, phylogeny, Diostrombus mkurangai, Elaeis guineensis, Borassus aethiopum, coconut beetle, Oryctes monoceros
Permanent URL:
ID Code:13381
Faculty:S - Faculty of Forest Sciences
Department:(NL, NJ) > Dept. of Forest Mycology and Plant Pathology
(S) > Dept. of Forest Mycology and Plant Pathology
Deposited By: Mr Joao Bila
Deposited On:17 May 2016 13:38
Metadata Last Modified:10 Sep 2020 13:41

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