The Effect of Cassava Mosaic Disease on Growth and Yield of a Local and an Improved Variety of Cassava

Terry, Elein; Hahn, S. K.

doi:10.1080/09670878009414280

Cited by 30 publications

(14 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In recording experiments and in screening for resistance to CMD, much use has been made of simple numerical scoring systems based on the extent and severity of the symptoms expressed. Following the pioneering work of Cours (1951) and Dulong (1971) in Madagascar, scales of 0 or 1 (symptomless) to 4 or 5 (most severe symptoms) have been used widely to quantify differences in symptom expression due to host genotype, season, stage of crop growth and virus strain, and in assessing the relationship between symptom severity and yield loss (Terry & Hahn, 1980; Muimba‐Kankolongo & Phuti, 1987; Fauquet & Fargette, 1990). Such scales have been used to categorize individual leaves or whole plants and, less satisfactorily, for whole plots in field trials and resistance screening.…”

Section: Cassava Mosaic Diseasementioning

confidence: 99%

“…Clones TMS 30337, TMS 30395 and TMS 30572 were raised at IITA in 1973. They are three of the first improved varieties that were shown to be resistant to CMD, yet they may sustain a substantial loss of yield when infected (Terry & Hahn, 1980; Terry, 1982). The most resistant of the TMS varieties, notably TMS 30001, are even more difficult to infect and, when infected, develop inconspicuous symptoms of restricted distribution.…”

Section: Possible Control Measuresmentioning

confidence: 99%

See 1 more Smart Citation

Strategies for controlling cassava mosaic virus disease in Africa

2005

View full text Add to dashboard Cite

Cassava mosaic disease (CMD) is caused by whiteflyborne viruses of the genus Begomovirus (family Geminiviridae ). The disease has long been regarded as the most important of those affecting cassava in sub-Saharan Africa, and has been the subject of much research, especially since the onset of the current very damaging pandemic in eastern and central Africa. This review considers the main features of CMD and the various possible means of control. The main emphasis to date has been on the development and deployment of virus-resistant varieties. These are widely adopted in countries where CMD has caused serious problems, and provided a powerful incentive for farmers to abandon some of the most susceptible of their traditional varieties. Only limited use has been made of phytosanitation involving CMD-free planting material and the removal (roguing) of diseased plants. Cultural methods of control using varietal mixtures, intercrops or other cropping practices have also been neglected, and there is a need for much additional research before they can be deployed effectively. Nevertheless, the severe losses now being caused by CMD in many parts of sub-Saharan Africa could be greatly decreased through the application of existing knowledge.

show abstract

Section: Cassava Mosaic Diseasementioning

confidence: 99%

Section: Possible Control Measuresmentioning

confidence: 99%

Strategies for controlling cassava mosaic virus disease in Africa

2005

View full text Add to dashboard Cite

show abstract

“…The CMD incidence represented the percentage of diseased plants compared to the total number of plants present in the plot. The CMD symptom severity was assessed for each plant in the plot using a scale of 1 to 5 described by Hahn et al, [12] and Terry and Hahn [13], where: 1 = no symptoms; 2 = mild chlorosis, mild distortions at bases of most leaves, while the remaining parts of the leaves and leaflets appear green and healthy; 3 = pronounced mosaic pattern on most leaves, narrowing and distortion of the lower one-third of the leaflets; 4 = severe mosaic distortion of two thirds of most leaves and general reduction of leaf size and stunting of shoots; and 5 = very severe mo-saic symptoms on all leaves, distortion, twisting, misshapen and severe leaf reductions of most leaves accompanied by severe stunting of plants.…”

Section: Data Recorded and Statistical Analysismentioning

confidence: 99%

Assessing Reactions of Genetically Improved and Local Cassava Varieties to Cassava Mosaic Disease (CMD) Infection in a Savannah Region of the DR-Congo

Muengula-Manyi¹,

Mukwa²,

Nkongolo³

et al. 2013

AJPS

View full text Add to dashboard Cite

The responses of eight genetically improved and eight local cassava varieties to cassava mosaic disease (CMD) were evaluated under field conditions at two sites, in Eastern Kasaï, region of the DR-Congo). The varieties were planted using randomized complete block design with three replications. The rate of cuttings sprouted varied significantly from variety to variety and from location to location. Local varieties were severely infected than improved varieties throughout the trial period. In general, the level of CMD incidence for genetically improved varieties was below 15% while it reached 100% for the local cassava varieties six months after planting (MAP). This trend was also observed for the CMD severity and gravity. The mean scores for CMD severity were 2 and 3.6 for genetically improved and local varieties, respectively at 6 MAP. CMD gravity for improved varieties was below 21% for genetically improved varieties and exceeded 85% for local varieties at the end of trials. Area Under the Severity index Progress Curve (AUSiPC) and Area Under Disease Progress Curve (AUDPC) estimates confirmed that improved varieties were moderately infested comparatively to local varieties. Molecular analysis is being conducted to determine the genetic variability and complexity of the cassava mosaic virus strains involved.

show abstract

“…The whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a widespread pest of crops in the tropics and sub-tropics (Terry and Hahn, 1980;Geddes, 1990). It is the vector of cassava mosaic geminiviruses (CMGs) that cause cassava mosaic disease (CMD) that leads to yield losses ranging from 15 to 27% in Africa (Thresh et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Occurrence and activity of Bemisia tabaci parasitoids on cassava in different agro-ecologies in Uganda

et al. 2005

View full text Add to dashboard Cite

Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) is the vector of cassava mosaic geminiviruses that cause cassava mosaic disease (CMD), which in turn causes devastating yield losses. Surveys were conducted from October 2000 to November 2001 in four agro-ecologies in Uganda to enhance the understanding of parasitoid fauna and parasitism of B. tabaci in cassava fields. Such an understanding is an essential prerequisite for the development of biological control methods of B. tabaci to complement current CMD control practices. Parasitoid abundance and parasitism efficiency varied between locations and sampling dates within the locations; highest parasitoid densities were observed at Namulonge in the Lake Victoria crescent while the lowest was at Kalangala. In all locations, parasitism was mainly due to Encarsia sophia Dodd and Girault and Eretmocerus mundus Mercet (all Hymenoptera: Aphelinidae). Two occasionally observed species included Encarsia mineoi Viggiani (Hymenoptera: Aphelinidae), only observed at Namulonge, and blackhead Encarsia (Hymenoptera: Aphelinidae) observed at Bulisa, Namulonge and Lyantonde. Parasitism efficiency was highest at Bulisa (57.9%), but ranged from 40.2 to 46.9% at the other three sites. This paper discusses the possible causes of variations in parasitoid abundance and parasitism efficiency, and proposes further studies that might be carried out to assess the potential for augmentation of parasitoids to control B. tabaci populations and CMD.

show abstract

The Effect of Cassava Mosaic Disease on Growth and Yield of a Local and an Improved Variety of Cassava

Cited by 30 publications

References 2 publications

Strategies for controlling cassava mosaic virus disease in Africa

Strategies for controlling cassava mosaic virus disease in Africa

Assessing Reactions of Genetically Improved and Local Cassava Varieties to Cassava Mosaic Disease (CMD) Infection in a Savannah Region of the DR-Congo

Occurrence and activity of Bemisia tabaci parasitoids on cassava in different agro-ecologies in Uganda

Contact Info

Product

Resources

About