ISPP Congress Challenge

Development of Appropriate Strategies to Control Cassava Diseases in Ghana

ISPP is glad to present this second Report, for 2005-6, of its Congress Challenge project on the management of cassava diseases in Ghana. It is hoped that this will be of value in other countries also.

Some striking quotations from the Report are highlighted here: 

• Farmers therefore requested the project to help them obtain healthy planting materials for their new farms. This request gave birth to a new idea. This is the setting up of Community Planting Materials Multiplication Fields with desired varieties that are disease resistant and high yielding.

• Community Planting Materials Multiplication Fields will eventually be owned and maintained by members of Field Schools in the future when the ISPP project is completed. From these multiplication fields healthy planting materials can be obtained for the establishment of new farms.

• The interesting development is that farmers with small land holdings are all willing to give land for the establishment of the community multiplication fields.

• This is the first time this thinking is emerging and a proud legacy will be left behind by the ISPP Congress Challenge Project if the idea of Community Planting Materials Multiplication Fields to supply healthy planting materials is successfully introduced into the national cassava production systems.

And, quoted from the First Report, for 2004-5:

• Famine rarely occurs in areas where cassava is grown widely because it provides a stable base to the food production system.

• Unfortunately however, majority of farmers in Ghana have very little or no knowledge of plant diseases and therefore, do practically little or nothing to control diseases. Majority of cassava farmers do consider some disease symptoms of the crop as normal features of the plant.

Associated with the First Report, for 2004-5 is the authors’ Disease Guide: Identification and Control of Root Rot Diseases of Cassava.

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

Address:

CSIR – Crops Research Institute
P. O. Box 3785
Kumasi, Ghana
E-mail: e.moses@cropsresearch.org

Implementing Institution: CSIR – Crops Research Institute, Ghana

Collaborating Scientists:

Dr J.N. Asafu-Agyei – CSIR-CRI
Mr. F. Ayueboteng – CSIR-CRI

Institution: MOFA – Ministry of Food and Agriculture, Ghana (Kpando District Directorate)

Duration of Project: 3 years.

Location of Project: Volta, Central, Ashanti and Eastern Regions of Ghana

Sponsor of Project: International Society for Plant Pathology (ISPP), through the competitive Congress Challenge scheme of the Task Force on Global Food Security. http://www.isppweb.org/foodsecurity_congresschallenge.asp

YEAR TWO REPORT: 2005-6

 See also Year One Report: 2004-5

 INTRODUCTION

Development of Appropriate Strategies to Control Cassava Diseases in Ghana’ is a 3-year project that resulted from an ISPP Congress Challenge Award. The project has just entered its third year and this is the report on second year’s activities. An important  primary objective of this project is to develop effective integrated strategies to control Polyporus root rot and other major diseases of cassava that threaten production of this important staple and industrial cash crop in Ghana. Activities being conducted to achieve the goals of the project include the development and deployment of varieties resistant or tolerant to Polyporus root rot fungus (Figure 1) and other major diseases of cassava such as African Cassava Mosaic Disease (ACMD), Cassava Anthracnose Disease (CAD) and Cassava Bacterial Blight (CBB) capable of causing 100% yield loss in susceptible cultivars. Strengthening the knowledge base of farmers and agricultural extension agents on cassava diseases and their control through farmer field schools, disease identification and control workshops and field days and introducing farmers in Polyporus endemic areas to other important root and tuber crops that can improve food security of farmers and their communities are some of the other activities of the project.

Figure 1. The bright yellow fruiting body of the cassava root rot mushroom, Polyporus sulphureus on a field to be cultivated with cassava

ACTIVITY ONE

Testing genotypes of cassava for resistance to Polyporus root rot and other diseases of the crop

Methodology

Participatory evaluation of eight (8) test genotypes of cassava for resistance to root rots and other diseases of cassava continued in the second year. Two (2) genotypes (the farmer’s local cultivar and Afisiafi) were included in the trials as checks. Harvesting of trials set up in the first year of project was completed in the second year. Harvesting started 12 months after planting and was completed 15 months after planting. This was to allow varieties that fit farmers’ practices to be identified for the study communities. Varieties that stay longer than one year in the soil but still maintain good root qualities are better preferred because these genotypes contribute more effectively to farmer’s food security in the Avemedra and Sabadu study areas.

Reaction of the genotypes to the Polyporus fungus and other major diseases of cassava such as African Cassava Mosaic Disease (ACMD), Cassava Anthracnose Disease (CAD) and Cassava Bacterial Blight (CBB) were documented over the 15 month period. Diseases were scored on a 1-5 scale (where 1= no visible symptom observed; 5= severe damage to tissues and organs of plant observed).

Results and Discussions

The areas of Sabadu and Avemedra are  high disease pressure areas for cassava. ACMD, CAD, CBB, bud necrosis and Polyporus root rot are the diseases observed in the locality.

The reaction of the test genotypes to the various diseases of cassava compared to checks are presented in Table 1.

African cassava mosaic virus infection continued to be an important disease with high incidence in Avemedra and Sabadu study communities. The farmers’ popular variety in the research trial was severely affected by ACMD (severity score of 4.0). Recorded ACMD severity in fields planting this genotype ranged between 3.5 and 5.0 in the study area.

The fruiting body of P. sulphureus was not observed growing on any of the test varieties during the 15 months of evaluation. The fruiting bodies of the parasitic mushroom were, however, present on adjacent fields during the period of evaluation. The genotype Afisiafi was included as a check because it is the most important variety cultivated currently for processing into industrial starch and ‘gari’(a local food from cassava) nationwide. This variety is known from previous studies to be susceptible to ACMD and Polyporus root rot. Its importance is due to its high yielding ability and high starch content. The new genotypes this project is introducing into the study area are, therefore, superior to the local farmers’ cultivar and Afisiafi in relation to ACMD (see Figures 2 and 3). Two of these varieties (already released into the national production systems) have high dry matter and starch content comparable to Afisiafi. Six of the eight introduced varieties yield higher than the farmers’ genotype. Three of these varieties gave root yields two times higher than the farmers’ local cultivar. Root quality of these varieties was good even at 15 months after planting (Figure 4). It is important to report that because of the good yields and resistance to ACMD and root rot diseases, farmers collected the stems of these varieties and carried them away to be used as planting materials on their own fields. These varieties, therefore, have started diffusing into the study communities earlier than anticipated.

The period of 15 months in which the evaluation occurred was characterized by irregular and poor rainfall distribution. Yields of varieties tested can therefore be higher than what was recorded in a season with normal rainfall distribution.

Two of the introduced varieties were also severely attacked by bud necrosis (Figure 5). Bud necrosis is a fungal infection that forms necrotic areas on buds resulting in poor sprouts from cuttings derived from infected stems. Observations made on farms in the two study communities indicate that incidence and severity of bud necrosis in the area is on the increase demanding conscious efforts for its control. The presence of brown leaf spot (BLS) disease and green cassava mite (GCM) was also recorded.

Table 1. Reaction of test genotypes to diseases (and pest) and root yields

Figure 2. Farmers’ popular local cultivar of cassava used as a check in the disease resistance testing trials. The leaves are expressing severe ACMD symptoms. This genotype is also susceptible to Polyporus root rot.

Figure 3. Test genotype cultivated on the same day as farmers’ local variety shown in Figure 2. This genotype is free from ACMD attack.

Figure 4. Farmers in the Avemedra Farmer Field School admiring harvested cassava roots from trials 15 months after planting

Figure 5. Cassava plant suffering from bud necrosis 

ACTIVITY 2

Disease Identification and Control Workshops

An important activity planned for the second year was to increase awareness of farmers and extension agents to new and important diseases of cassava that reduce yields in production areas. In collaboration with extension services of the Ministry of Food and Agriculture (MOFA), four important cassava growing districts experiencing high disease pressures were selected for the Workshops.

Farmers and extension agents in the Ejura-Sekyere Dumase district (Ashanti region), Gomoa district (Central region), Kpando and Hohoe districts (Volta region) participated in the Workshops. Incidence of Polyporus root rot of cassava in the Kpando and Gomoa districts is significant.

MOFA District Directorates helped in the selection of farmers that participated in the Workshops. In the Kpando district, representatives of the project’s Farmer Field School at Avemedra and Sabadu participated in the Workshop.

The Workshops focused on disease identification and practical methods of disease control including the application of improved cultural practices. Participants were trained in simple integrated systems of disease control. The selection of suitable land for cassava production, use of healthy planting materials, roguing to reduce spread of diseases, good farm sanitation and selection of suitable varieties to meet farmers’ requirements were some of the areas covered in the Workshops. Farmer s’ production experiences (particularly on diseases) were introduced by farmers and extension agents from the districts for discussions. The need to control diseases to improve on yields, food security and earnings of farmers were emphasized. A number of production constraint issues were raised and discussed.

Training focused on the use of easy-to-recognize symptoms of diseases in identification. One hundred and forty-three individuals were trained in disease identification and control.

Figure 6.  Disease Identification and Control Workshop with Farmers and Extension Agents from Gomoa District organized at Apam in the Central Region.

 Figure 7.   Disease Identification and Control Workshop with Farmers and Extension Agents from Kpando District organized at Kpando in the Volta Region.

  Figure 8.  Disease Identification and Control Workshop with Farmers and Extension Agents from Hohoe District organized at Hohoe in the Volta Region.

 Figure 9.  Disease Identification and Control Workshop with Farmers and Extension Agents from Ejura-Sekyere Dumase District organized at Ejura in the Ashanti region.

ACTIVITY 3

Farmer Field School (FFS)

Farmer Field School activities continued in the second year. Farmers were taken through lessons in good land selection, methods of land preparation, handling of plant debris (particularly from diseased fields) after harvest, disease identification based on symptoms, selection of suitable varieties, selection of healthy planting materials and adopting recommended improved agronomic practices. Post-planting practices such as regular field walks for early detection of diseases, roguing, and maintenance of good farm sanitation were the other areas covered in the Field School. The Field School uses the participatory learning approaches where school members bring problems from their farm set-up for discussions. Visits to farms of FFS members to hold school sections or ‘disease control clinics’ with neighbouring farmers were arranged and these will be continued as they helped monitor the use of knowledge acquired from the Field Schools by farmers. Field visits allow specific advice also to be given to farmers based on circumstances on their individual farms. Some of the FFS activities in the second year are shown in Figures 10, 11, 12 and 13 below.

Figures 10.  Some of the members of the FFS receiving specific lessons on how to handle the parasitic mushroom P. sulphureus during land preparation at Avemedra.

Figure 11. Some of the farmers from the Avemedra FFS and a research scientist sharing experiences on the cassava root rot mushroom at land preparation. The arrow is pointing to a fruiting body of the parasitic mushroom.

Figure 12. Examination of cassava stems to strengthen disease identification skills required for the selection of healthy planting material at a Farmer Field School section.

Figure 13. A female farmer sharing her experiences on cassava diseases with other farmers and a research scientist at an FFS section.

ACTIVITY 4

Introduction of sweetpotato varieties

Two orange and two white fleshed varieties of sweetpotao with high yielding characteristics and good cooking qualities were introduced into the study communities at a nursery site. Irregular rainfall pattern and a long dry period in the second year resulted in poor plant establishment. Vines of the introduced varieties had to be conserved to avoid complete loss of planting materials. Multiplication of these vines has started and demonstration plots of these varieties will be set up at an appropriate time in the third year. This report confirms the advantages of cassava over sweetpotato in rain fed agricultural systems where irrigation facilities are largely unavailable.

ACTIVITY 5

Development of disease control literature

Development of disease control literature continued in the second year. A guide on the Control of Cassava Bacterial Blight (CBB) was developed in the second year. The guide will be submitted for posting at the ISPP website.

Publishers helping and guiding the development of disease control literature and other extension materials have advised that a single booklet guide on cassava diseases and their control will be easy to use by farmers and extension agents (farmers in particular will not wish to own a separate publication on each cassava disease). Literature development on ACMD, CAD, bud necrosis and the leaf spot diseases therefore are scheduled to be completed, fully edited and ready for publishing by the end of January 2007.

Practical disease control techniques in demonstration to be produced on audio-visual compact discs for extension programmes are scheduled for completion by the end of February 2007.

GENERAL DISCUSSIONS

Disease Resistance Genotypes, Workshops and Farmer Field Schools

The Workshops allowed adequate discussions and interactions among farmers, extension agents and researchers. Farmers keenly participated in the Workshops introducing unique problems from their set-ups and their communities for discussions and solution. Experience sharing was an important feature of the Workshops and FFS activities.

Farmers from the Workshops and Field Schools presented issues that confirmed they appreciate the objectives the project is working to achieve. Farmers (from the Workshops and Field Schools) made a common submission that they hardly obtain enough healthy planting materials for their new farms. They submitted that they unwillingly continue to use diseased planting materials to establish new farms even though they now know this practice increases disease severity and spread, leading to yield losses.

Community Planting Materials Multiplication Fields

Farmers therefore requested the project to help them obtain healthy planting materials for their new farms. This request gave birth to a new idea. This is the setting up of Community Planting Materials Multiplication Fields with desired varieties that are disease resistant and high yielding.

Community Planting Materials Multiplication Fields will eventually be owned and maintained by members of Field Schools in the future when the ISPP project is completed. From these multiplication fields healthy planting materials can be obtained for the establishment of new farms.

For a start, varieties from the resistance testing experiments of this project with proven disease resistance attributes that are also high yielding will be multiplied at community fields. The interesting development is that farmers with small land holdings are all willing to give land for the establishment of the community multiplication fields.

This is the first time this thinking is emerging and a proud legacy will be left behind by the ISPP Congress Challenge Project if the idea of Community Planting Materials Multiplication Fields to supply healthy planting materials is successfully introduced into the national cassava production systems.

Processing

Analysis of the Polyporus root rot situation in the two communities of Avemedra and Sabadu indicate that the spread of the root rot disease from these communities into new areas will be reduced if harvested roots of cassava are processed within the communities into ‘gari’ and ‘agbelima’ (two important food products eaten extensively in most parts of the country, particularly the Volta region). This project will consider facilitating the setting up of appropriate processing facilities for the two communities.

THIRD YEAR PROJECT ACTIVITIES

1. The Avemedra and Sabadu Field Schools will be helped to set up Community Planting Materials Multiplication Fields using the varieties that have been identified and reported on in Activity 1 to have resistance to root rots and other major diseases of cassava.

2. Plans are well advanced for the setting up of demonstration plots with good varieties of sweetpotato. Sweetpotato has a short life cycle and after a good season’s demonstration lasting about five months, farmers of the Field School will be provided with vines of varieties they desire to plant and produce on their own farms. The performance of the varieties in the hands of farmers in the communities will be monitored.

3.Training of farmers in disease control methodologies will continue in the Field Schools. Farmers who successfully participate in Field School activities to the end of the project will be presented with Certificates of Participation.

4. More strategic Workshops on Disease Identification and Control will be held for new participants.

5. Literature development on disease control will continue. A complete guide to the control of cassava diseases (booklet) with information on all the major diseases of the crop will be published and distributed towards the end of the third year. A compact disc version on the practical methods of disease control will be produced at the end of the third year. Distribution of produced extension materials will be made to cassava farmers, farmer groups, MOFA District Directorates, and libraries of secondary and tertiary institutions offering and developing agriculture.

6. Surveys to document disease levels in the Avemedra and Sabadu study area towards the end of the third year will be conducted to give a measure of the impact of the project on the two communities.

7. The final technical report of the project will be completed and submitted at the end of the third year of the project.

8. Preparations will be made towards final reporting on the Activities and Achievements of the ISPP Congress Challenge Project at the next Congress in 2008.

REPORT WAS PREPARED BY E. MOSES (Ph.D. Plant Pathology)

CSIR-CROPS RESEARCH INSTITUTE, KUMASI, GHANA