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Development of Appropriate Strategies to Control Cassava Diseases in Ghana

Principal Scientist and Author: E. Moses (Ph.D., Plant Pathology)


CSIR � Crops Research Institute
P. O. Box 3785
Kumasi, Ghana

Implementing Institution: CSIR � Crops Research Institute, Ghana

Duration of Project: 3 years, 2004-2007.

Sponsor of Project: International Society for Plant Pathology (ISPP), through the competitive Congress Challenge scheme of the Task Force on Global Food Security.

Executive Summary

See also

Year One Report: 2004-5
Year Two Report: 2005-6

The proposal entitled "Development of Appropriate Strategies to Control Cassava Diseases in Ghana", submitted by Emmanuel Moses of Crops Research Institute (Ghana) received the first ISPP Congress Challenge Award. The award was used to support the implementation of the activities in the proposal to develop appropriate integrated system of disease control strategies that reduce yield losses, improve food security and enhance income generation of cassava farmers who are more than half of the farming population of the country. It was a three year project.

Cassava is the most important staple food crop in Ghana and in recent years is also becoming an important industrial raw material for food and starch based industries. It has been reported in the COSCA studies on cassava that in the 1983 famine in Ghana, communities that coped better in that uncomfortable situation were cassava based farming communities. Cassava can be processed into a number of important food products including 'gari' that can store for over a year when well prepared without any loss in food quality. Cassava chips when properly dried can store for a year or more without any loss in quality. These attributes make cassava an important food security crop in Ghana and several sub-saharan African countries that produce the crop. Unfortunately, cassava is affected by many pathogens that are well adapted to conditions in several cassava producing countries. African Cassava Mosaic Disease (ACMD), Cassava Bacterial Blight (CBB), Cassava Athracnose Disease (CAD), Bud Necrosis and root rot diseases particularly rots caused by the mushroom Polyporus sulphureus cause significant yield losses in several farming communities. ACMD and CAD are very widespread in Ghana. Polyporus root rot is capable of causing complete crop failure.

The three year Congress Challenge Project was aimed at developing appropriate disease control strategies that will empower farmers to recognize the need to control diseases and implement programmes on their own using simple technologies and improved cultural practices to reduce yield losses on their farms.

The project has been completed and some of its important achievements include making the people of Sabadu and Aveme in the Volta Region of Ghana know that the Polyporus root rot infection can be controlled. The two communities were Polyporus endemic areas with high disease incidence. Farmers in these two communities now consciously control cassava diseases on their farms using introduced improved varieties and simple cultural practices including burning plant debris carrying fruiting bodies and other pathogens after harvest. Farmers from the two communities will do everything possible now to obtain healthy planting materials to begin new farms. A significant drop in Polyporus root rot incidence from 80% in 2001 to 40% in 2007 in the two project communities indicate that farmers spend time in controlling diseases on their farms.

Three years of farmer field school (FFS) activities in the two project communities have actually helped in equipping farmers with basic knowledge in disease control. Sixty farmers from the two project communities participated in the farmer field school activities under the project. These farmers were trained to identify diseases and control them. They were encouraged to transfer skills and techniques to neighboring farmers who did not participate in the field school. An outbreak of a disease on an ignorant farmer's field is just a potential threat to your own farm. This fact was emphasized throughout the duration of the field school.

Disease awareness and control workshops were organized for farmers and extension agents in four major cassava producing districts (Gomoa, Ejura-Sekyere, Kpandu and Hohoe). Over 200 farmers and extension agents were trained in disease identification and control methods. The strategic selection of these districts for training helped in reducing the spread of Polyporus root rot of cassava into new districts. Hohoe for example shares a boundary with Kpandu district but sensitization and activities of Extension agents and farmers trained at workshops might be responsible for the current absence of Polyporus root rot in the Hohoe district. Extension agents and farmers who were trained at these workshops were encouraged to transfer the knowledge acquired to friends, neighbours and colleagues.

The project tested nine new varieties of cassava for resistance to Polyporus root rot and other major diseases of cassava. Seven of the varieties introduced into the project communities performed better than the popular farmer's local variety in the Polypyorus endemic area in terms of yield and resistance to ACMD. Three of the introduced varieties, 96/0160, 96/1642 and Afisiafi each produced roots higher than 22.0 t/ha compared to the farmer's popular variety that yielded 11.0 t/ha and is also susceptible to ACMD. These varieties have already diffused into the farming systems of the two project communities because of the participatory methods used in this project. Farmers in the two communities now have increased access to more cassava germplasm with different processing qualities. This can increase economic activity for the farmers. The introduced varieties have high resistance to ACMD and this can reduce incidence of this major cassava disease eventually in the Kpando district. Effective management of the higher yields eventually can improve food security and incomes in the project communities.

Farmers have acquired skills and are capable of establishing healthy planting materials multiplication fields to ensure continuous supply of healthy planting materials for their planting operations within the two project communities.

The project consciously introduced five high yielding sweetpotato varieties into the Polyporus endemic study communities to improve access to other alternate sources of carbohydrates to reduce overdependence on cassava. The five introduced varieties, 'Faraa', 'Sauti', 'CRI-Otoo', 'CRI Apomuden' and 'CRI-Ogyefo' started diffusing into the two communities on the first day the cultivars were introduced to the farmers. Farmers actively collected vines and planted them on their own farms.

A good market for sweetpotato is available in the Volta Region (Kpando District is in the Volta Region). It is anticipated that the introduced sweetpotato varieties will not only improve food security of the project communities but be a good source of income if farmers produce sweetpotato on large scale. The variety 'CRI-Apomuden' is an orange flesh cultivar with high beta carotene levels and therefore can prove very useful in the fight against vitamin A deficiency particularly among children and pregnant women in the communities.

A thirty-two page disease identification and control guide for cassava was written and produced as a major output of the Congress Challenge Project (Year 3 report). Five hundred hard copies of the booklet have been printed and are being distributed to schools and universities in Ghana. The booklet has been accepted by reviewers including university professors and the demand from extension and agricultural science students from second cycle and tertiary institutions is increasing. This booklet has filled a vacuum that existed and needed to be filled to improve on production of this important staple food of many Ghanaians. For several years to come this booklet will remain an important extension guide for the identification and control of cassava diseases.

The project also produced a single DVD on cassava disease identification and control as an extension material for schools and agricultural extension agents. Symptoms of all the major diseases of the crop are well presented in pictures with simple descriptions that make identification an easy exercise. Simple techniques that can easily be followed to control any of the major diseases of cassava can be found on the disc. Information on ACMD, CBB, CAD, Bud Necrosis and the leaf spot diseases are available . Distribution of the discs to second cycle and tertiary institutions and organizations that deal with mass extension services will start immediately when issues to prevent illegal copying for sales are completed.