What has changed in the outbreaking populations of the severe crop pest whitefly species in cassava in two decades?

Ally Hadija, El Hamss Hajar, Simiand Christophe, Maruthi M.N., Colvin John, Omongo Christopher A., Delatte Hélène. 2019. What has changed in the outbreaking populations of the severe crop pest whitefly species in cassava in two decades?. Scientific Reports, 9:14796, 13 p.

https://doi.org/10.1038/s41598-019-50259-0

Article de revue ; Article de recherche ; Article de revue à facteur d'impact Revue en libre accès total

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Quartile : Q1, Sujet : MULTIDISCIPLINARY SCIENCES

Résumé : High populations of African cassava whitefly (Bemisia tabaci) have been associated with epidemics of two viral diseases in Eastern Africa. We investigated population dynamics and genetic patterns by comparing whiteflies collected on cassava in 1997, during the first whitefly upsurges in Uganda, with collections made in 2017 from the same locations. Nuclear markers and mtCOI barcoding sequences were used on 662 samples. The composition of the SSA1 population changed significantly over the 20-year period with the SSA1-SG2 percentage increasing from 0.9 to 48.6%. SSA1-SG1 and SSA1-SG2 clearly interbreed, confirming that they are a single biological species called SSA1. The whitefly species composition changed: in 1997, SSA1, SSA2 and B. afer were present; in 2017, no SSA2 was found. These data and those of other publications do not support the 'invader' hypothesis. Our evidence shows that no new species or new population were found in 20 years, instead, the distribution of already present genetic clusters composing SSA1 species have changed over time and that this may be in response to several factors including the introduction of new cassava varieties or climate changes. The practical implications are that cassava genotypes possessing both whitefly and disease resistances are needed urgently.

Mots-clés Agrovoc : Bemisia tabaci, Manihot esculenta, virus mosaïque manioc, virose, variation génétique

Mots-clés géographiques Agrovoc : Ouganda

Mots-clés complémentaires : virus de la striure brune du manioc

Mots-clés libres : Ecology, Molecular biology

Classification Agris : L10 - Génétique et amélioration des animaux
H10 - Ravageurs des plantes
H20 - Maladies des plantes

Champ stratégique Cirad : CTS 4 (2019-) - Santé des plantes, des animaux et des écosystèmes

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