Methods of surveying the incidence and severity of cassava mosaic disease and whitefly vector populations on cassava in Africa: a review

Sseruwagi, Peter; Sserubombwe, W.; Legg, J.P.; Ndunguru, Joseph; Thresh, J. M.

doi:10.1016/j.virusres.2003.12.021

Cited by 152 publications

(181 citation statements)

References 35 publications

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“…These differences were not very pronounced, and the general disease situation was of relatively severe disease when comparing data with averages for other countries (Sseruwagi et al, 2004b). This could be attributed to the high frequency of occurrence of mixed virus infections, known to elicit more severe symptoms through synergistic interactions Fondong et al, 2000;Pita et al, 2001).…”

Section: Discussionmentioning

confidence: 91%

Incidence and severity of cassava mosaic disease in the Republic of Congo

Ntawuruhunga¹,

Okao-Okuja²,

Bembe³

et al. 2010

African Crop Science Journal

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Diagnostic surveys were conducted in 2002 and 2003 in order to provide a comprehensive and detailed assessment of the status of cassava mosaic disease (CMD) in the Republic of Congo (ROC) and to determine if the disease was spreading. In 2002, 105 farmers' fields were assessed in the four major cassava-producing regions of the country. In 2003, 163 fields were sampled in nine regions and Brazzaville Commune. Incidence of cassava mosaic disease was generally high, averaging 80 and 86 % for 2002 and 2003, respectively; while damage was moderate to severe. In 2002, disease incidence was moderate in Pool (73%) but high in Brazzaville (81%), Cuvette Centrale (82%) and in Plateaux Region (84%). Pool region still had the lowest incidence (78%) in 2003, while Sangha (95%) had the highest incidence. The greatest disease severity was recorded in Niari region in the south and Cuvette Ouest region in the north in 2003. East African cassava mosaic virus Uganda variant (EACMV-UG) occurred virtually throughout the country, commonly in dual infections with African cassava mosaic virus. The high incidence of disease in plants considered to be the results of cutting infection (74% in 2002 and 82% in 2003), relatively low incidence of disease in plants considered to be infected by whiteflies and wide distribution of EACMV-UG points to the fact that the CMD pandemic is a chronic in the country and the areas sampled are currently in a stable post-epidemic phase. This situation is comparable to that in areas of East Africa affected by a pandemic during the 1990s, including Uganda, parts of western Kenya and north-western Tanzania. These findings clearly verify the assertion that the CMD pendemic has expanded across Central Africa and provide a basis for designing interventions and control strategies for the entire region. dans la région du Pool demeurait encore plus faible (78%) en 2003 pendant que Sangha avait l'incidence plus élevée (95%). En 2003 la plus grande gravité de la maladie était enregistrée dans la région de Niari au Sud et dans la région Ouest de la cuvette au Nord. La variante du virus de la mosaïque du manioc de l'Afrique de l'Est en Ouganda (VVMMAEO) s'était virtuellement manifestée à travers le pays; les infections s'étaient couplées avec le virus de la mosaïque du manioc africain. La grande incidence de la maladie des plantes considérée être les résultats de la contagion des boutures était de 74% en 2002. Relativement, la basse incidence dans les plantes considérées être contaminées par les mouches blanches et la grande part du VVMMAEO était de 82% en 2003. Ceci a abouti à la conclusion selon laquelle la pandémie de la MMM avait contaminé le pays quelques années auparavant et que les régions ayant fait l'objet de l'échantillon sont actuellement dans une phase post-endémique. Cette situation est comparable à celle des régions de l'Afrique de l'Est qui étaient contaminées par une pandémie les années 1990 y compris l'Ouganda, les parties Ouest du Kenya et le Nord-Ouest de la Tanzanie.

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Section: Discussionmentioning

confidence: 91%

Incidence and severity of cassava mosaic disease in the Republic of Congo

Ntawuruhunga¹,

Okao-Okuja²,

Bembe³

et al. 2010

African Crop Science Journal

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“…Four months after planting (MAP), apparently healthy yam plants were identified and tagged using ribbons (positive selection- Figure 1a). The identified yam plants were assessed for yam mosaic virus (Figure 1b) using the scale of 1-5 [11] and YMV incidence on the scale of 0 or 1 [11]. Samples of yam leaves were screened in the laboratory to detect YMV and confirm visual/phenotypic assessment using polymerase gel resolution test.…”

Section: Advances In Crop Science and Technologymentioning

confidence: 99%

The Response of White Yam (Dioscorea rotundata Poir) Tuber Portions to Positive Selection for Quality Seed Yam Production

Aihebhoria¹,

Aighewi²,

Balogun³

2017

Adv Crop Sci Tech

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The production of yams is constrained by high cost and unavailability of clean planting materials, pests and diseases. Vegetative propagation has also caused a build of up diseases, reported to cause up to 80% yield reduction due to scarcity of quality declared seeds. Planting of disease-free material has been found to be effective in reducing disease problems in plants. This study was conducted to produce clean seed yam by reducing yam diseases through positive selection method. In this method, apparently healthy yam plants were identified, tagged (positive selection), assessed for yam mosaic virus incidence and severity using the scale 0 or 1 and 1-5 respectively. The harvested clean tubers from tagged plants were planted the following season so as to determine the rate of response of each genotype and tuber portion to positive selection. At the end of two cycles of positive selection, analysis of variance for percentage number of positive yam plants, YMV incidence, YMV severity and tuber yield shows significant difference (p ≤ 0.05) between positive selection and no selection for both field and screen house plants. It was observed that positively selected plants performed significantly (p ≤ 0.05) better than no selection plants. For field experiment, Number of positively selected plants was highest in positive TDr89/02665 with mean value of 75.00% while no selection Ogoja had the least number of positive plants (17.8%). A yield increase of 1.80 t/ha was recorded due to the application of positive selection method in two cycles. For screen house experiment, result followed a similar trend; however with a reduction in YMV incidence and severity. It is worthy to note that tail portions of yam were lest infected with YMV, hence more healthy plants were selected from the tail portion.

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“…This investigation had been carried out in 25 agricultural farmers'fields of 13 villages randomly chosen into the four principal road axes of "«Secteur de Boko»" (RN1, RN12, RS116, RS117 and Route de Zongo) in accordance with the technique suggested by Wydra and Msikita (1998) and also advised by Sseruwagi et al (2004). The administrative entity «Secteur de Boko» belongs to MbanzaNgungu Territory in Bas-Congo Province (South-western DRCongo).…”

Section: Site Of Study and Techniques Of Samplingmentioning

confidence: 99%

A cassava mosaic disease epidemiologic factors analysis in the Bas-Congo (DR Congo) zone of savannah. case study: â€œSecteur de Bokoâ€

J.-Roger

2015

IJBR

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This paper aims at evaluating epidemiologic parameters of the African Cassava Viral Mosaic Disease (CMVD) in 25 cassava farmer's fields of «Secteur de Boko» (DR Congo) on the basis of foliar symptoms observation. The results showed that the infection of the local varieties comes mainly from the cuttings whereas that of the improved varieties comes from the flies. The disease incidence varied between 10% and 88.33% with an average of 43.8%. Severity varied between 2.42 and 3.42 with an average of 2.913. The gravity varied between 17.86% and 87.81% while the systemicity varied between 21.42 and 96.66%. The mean number of whiteflies (Bemisia tabaci) by plant (2.068) revealed a preference of the vectors for the improved variety Kindombe which, however, presents a low severity and a less marked gravity. Globally, the CMVD was more severe for the local variety Mpeko with a score of 3.00. A high correlation was found between the gravity and the number of neighbour fields (-0,437*), the density of culture (-0,431*) and also the systemicity of the disease (0,779**). In addition; it appeared that the land topography strongly influences the disease severity (-0,542**).

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Methods of surveying the incidence and severity of cassava mosaic disease and whitefly vector populations on cassava in Africa: a review

Cited by 152 publications

References 35 publications

Incidence and severity of cassava mosaic disease in the Republic of Congo

Incidence and severity of cassava mosaic disease in the Republic of Congo

The Response of White Yam (Dioscorea rotundata Poir) Tuber Portions to Positive Selection for Quality Seed Yam Production

A cassava mosaic disease epidemiologic factors analysis in the Bas-Congo (DR Congo) zone of savannah. case study: â€œSecteur de Bokoâ€

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Methods of surveying the incidence and severity of cassava mosaic disease and whitefly vector populations on cassava in Africa: a review

Cited by 152 publications

References 35 publications

Incidence and severity of cassava mosaic disease in the Republic of Congo

Incidence and severity of cassava mosaic disease in the Republic of Congo

The Response of White Yam (Dioscorea rotundata Poir) Tuber Portions to Positive Selection for Quality Seed Yam Production

A cassava mosaic disease epidemiologic factors analysis in the Bas-Congo (DR Congo) zone of savannah. case study: â€œSecteur de Bokoâ€

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A cassava mosaic disease epidemiologic factors analysis in the Bas-Congo (DR Congo) zone of savannah. case study: â€œSecteur de Bokoâ€