«the incidence of bacterial wilt (ralstonia solanacearum) in informal potato planting materials used by farmers in dedza and ntcheu districts of ...»
the incidence of bacterial wilt (ralstonia
solanacearum) in informal potato planting
materials used by farmers in dedza and ntcheu
districts of malawi.
justin dickson zayamba kagona
Master Thesis 30 credits 2008
Department of international environment and development studies
The incidence of Bacterial wilt (Ralstonia solanacearum) in informal potato planting
material used by farmers in Dedza and Ntcheu districts of Malawi
Justin Dickson Zayamba Kagona
A thesis submitted in partial fulfillment of the requirement for the degree of Masters of Science (Management of Natural Resources and Sustainable Agriculture) Norwegian University of Life Sciences Noragric Department Norwegian University of Life Sciences (UMB) P.O. Box 5003, 1432 Ås, Norway May 2008 Credit The Department of International Environment and Development Studies, Noragric, is the international gateway for the Norwegian University of Life Sciences (UMB), eight departments, associated research institutions and the Norwegian College of Veterinary Medicine in Oslo. Established in 1986, Noragric’s contribution to international development lies in the interface between research, education (Bachelor, Master and PhD programmes) and assignments.
The Noragric master theses are the final theses submitted by the students in order to fulfill the requirements under the Noragric Master programmes “Management of Natural Resources and Sustainable Agriculture” (MNRSA), “Development Studies” and other Master programmes.
The findings, interpretations and conclusions in this thesis do not necessarily reflect the views of Noragric. Extracts from this publication may only be reproduced after prior consultation with the author and on condition that the source is indicated. For rights of reproduction or translation contact Noragric.
© Justin Dickson Zayamba Kagona, May 2008 E-mail: firstname.lastname@example.org Noragric Department of International Environment and Development Studies Norwegian University of Life Sciences (UMB) P.O. Box 5003 N-1432 Ås Norway Tel.: +47 64 96 52 00 Fax: +47 64 96 52 01 Internet: http://www.umb.no/noragric ii Declaration I, Justin Dickson Zayamba Kagona, declare that this thesis is a result of my research investigations and findings, under the supervision of Dr Trygve Berg of UMB and Dr Paul Demo of CIP Malawi. Sources ofinformation other than my own have been acknowledged and a reference list has been appended. This work has not been previously submitted to any other university for award of any type of academic degree.
Signature:……………… Date………………… iii Dedication Dedicated to my beloved wife and son, Jessie and Jeremiah; my father, for their encouragement and support and the soul of my mother who died during my thesis research. May her soul rest in eternal peace until we meet again.
iv Acknowledgements I would like to express my sincere thanks to my supervisors Professor Trygve Berg of Norwegian University of Life Sciences (UMB) for the constructive comments all the way from the proposal development to thesis writing. I greatly appreciate Dr Paul Demo of CIP Malawi (local supervisor), you are precious to me; your guidance in the field, thesis structure has made me to be the way I am. God bless you.
Special thanks go to the Norwegian government for sponsoring my Master in Management of Natural Resources and Sustainable Agriculture (MNRSA) studies here at UMB through the NORAD scholarship. May peace and love keep on prevailing in this country.
Special thanks also goes to Dr Pamela Anderson the Director General of the International Potato Center (CIP) with headquarters in Peru for coming to University of Life Sciences (UMB) and making it possible that we do the research in this field and link us to the CIPMalawi office headed by Dr Paul Demo. Further more I would like to thank CIP for providing the DAS-ELISA kit and other apparatus, logistics during field work and laboratory work and personnel which made our research possible. It’s really the precious support one prays to have.
Sincere thanks goes to the Officer In charge of Bvumbwe Agricultural Research Station, Malawi for allowing the DAS-ELISA test to take place at their station with all the support of the staff in Pathology and Horticultural department (Mr Misheck SokoPathologist, Mr O. Mwenye-Horticulturalist, Mr Z. Langisi, Miss Agather Banda, and Miss Hillale Mang’anda –Research Assistants).
Thanks to my wife, parents, brothers and sisters and my son for moral support. I praise God for having you.
Thanks again go to the Ministry of Agriculture head office in Lilongwe precisely the Crop Production Department for always being available whenever needed. The Director v of Crops Department Mr. Nyandule Phiri who made it all possible that I come here.
Thanks also go to Mr. James Kwanthe for supporting me when ever possible. My heartfelt thanks are to the Zomba District Agricultural office: the DADO and officers (Mr.
Francis Mpeketula for the support during my studies, I cherish you guys.
Thanks go to field officers and farmers from Dedza and Ntcheu for providing such precious information.
I acknowledge the support of a friend (more than a friend now), Mr. Diress T. Alemu, the then PhD student from Mekelle University in Ethiopia but under Ecology and Natural Resources department here at UMB for his endless support on organizing and analyzing of data. Without you brother I would have tough going. May God bless you evermore.
I would fail without acknowledging the Malawians lived together in Ås, Norway for being a family to me. The urgent response when need be was great to me. May God bless you all fore-ever and ever.
Finally, thanks to everybody who in a way or another contributed their moral support.
May Almighty God bless you forever and more!
vi Abstract Bacterial wilt caused by Ralstonia solanacearum (Smith) is a big problem in potato industry in Malawi since it reduces productivity, quality and storability of harvested tubers. In order to quantify the incidence levels, farmers’ knowledge on identification, spread and control of this disease, survey was conducted with 81 respondent farmers and, 489 tubers randomly collected in eight major markets were subjected to visual observation followed by test for latent infection in a laboratory using DAS-ELISA method. A structured questionnaire with a few open questions was administered to the 81 randomly selected farmers from two major potato producing areas. Forty-one farmers were from two Extension Planning Areas (EPA) of Ntcheu: Tsangano and Njolomole with 28 and 13 farmers respectively. Similarly forty farmers from Dedza came from Bembeke EPA and Lobi EPA with 13 and 27 farmers respectively. The questionnaire covered issues such as land holding size, cropping systems practiced, sources of seed and seed selection system, major potato diseases, knowledge and their sources in bacterial wilt identification, spreading, control, varieties grown, cultural practices and their impact to bacterial incidences in their fields. Data were analyzed with Excel, Minitab and SPSS to have descriptive statistics. Chi-square test, one way ANOVA and General linear model analysis were done using Sigma package appropriate for nonparametric data.
Results showed that 100% of the farmers were aware of the occurrences of bacterial wilt in their field and how it spreads. However the knowledge to control the disease varied between districts with Dedza at an upper hand due to involvement of NGOs and extension services following training by CIP. Source of knowledge in Ntcheu district was basically from friends rather than technical sector. The incidence levels in tested tubers were generally high ranging from 25.3% to 64.0%. There was no significant difference between bacterial wilt incidence levels obtained in the two districts. The highest incidence of 64.0% recorded in tubers from Mlangeni market of Ntcheu district was significantly higher (p 0.016) those obtained at Kalinyeke (27.1%) and Padipi (25.3%) of Dedza. A significantly lower bacterial wilt incidence was recorded with Violet variety compared to Roslyn. The incidence level of bacterial wilt was higher than 25% in all varieties tested. Violet had the lowest incidences (26.2%). These results confirmed that vii bacterial wilt is a great problem and threat to the Malawi potato industry. A clean seed producing industry needs to be put in place to clean up long released degenerated cultivars as well as provide quality seed of new varieties to be released from on-going selection process in the country. The country wide farmer education program initiated in positive and negative selection has to continue as it showed some positive impact in improving productivity in Kenya.
Table of Contents
List of Figures
List of Tables
List of Appendices
CHAPTER ONE - INTRODUCTION
1.1.1 Cultivated areas
1.5 Thesis Structure
CHAPTER TWO - LITERATURE REVIEW
2.1 Productions in Malawi
2.1.1 Cultivated varieties
2.2 Bacterial wilt
220.127.116.11 Simple techniques
18.104.22.168 Serological techniques
22.214.171.124.1 Enzyme-linked immunosorbent assay (ELISA)
126.96.36.199.2 Polymerase chain reaction
188.8.131.52 Cultural and sanitary practices
184.108.40.206 Biological control
220.127.116.11 Chemical control
CHAPTER THREE - MATERIALS AND METHODS
3.1 Study Area
3.2.1 Field Survey
3.2.2 Laboratory work
18.104.22.168 Visual observation
22.214.171.124 DAS-ELISA test
CHAPTER FOUR - RESULTS AND DISCUSSION
4.1 Field Survey
4.1.1 Potato production
126.96.36.199 Planting spacing
188.8.131.52 Planting materials
184.108.40.206 Fertilizer application
220.127.116.11 Major Diseases and Pests Reported by Farmers
4.1.2 Detection of bacterial wilt
18.104.22.168 Knowledge on Detection of PBW by district and sex
22.214.171.124 Sources of Information on PBW Detection
126.96.36.199 PBW Disease Detection Criteria
188.8.131.52 Knowledge on Spreading of PBW
184.108.40.206 Sources of Information on spreading of PBW (N = 81)
220.127.116.11 Farmers’ Knowledge in Effectively Controlling BW
4.2 Laboratory work
4.2.1 Incidences of bacterial wilt between the districts in general
4.2.2 Incidences of bacterial wilt among the markets
4.2.3 Incidences of bacterial wilt among varieties
4.2.3 Comparison of two methods from different:
CHAPTER FIVE – CONCLUSION AND RECOMMENDATION
x List of Figures Figure 2.1: Potato Production in Malawi since 1992/93
Figure 3.1: Map of Malawi with areas under study
Figure 4.1: Planting spacing practiced by farmers in Ntcheu and Dedza
Figure 4.2: Sources of potato planting materials used by farmers
Figure 4.3: Ways how farmers store their potato seed
Figure 4.4: Proportions of fertilizers used by farmers in Ntcheu and Dedza district.
...... 23 Figure 4.5: Mean incidence (%) of bacterial wilt in tubers in the two regions................. 36 Figure 4.6: Mean incidence (%) of bacterial wilt in tubers for five varieties
xiList of Tables
Table 4.1: Farmers’ response on number of crops per season (N = 81)…………………20 Table 4.
2: Farmers’ responses on effect of fertilizers on incidences of bacterial wilt..... 24 Table 4.3: Proportion (%) of farmers that reported major diseases and pests in both districts (N = 81)
Table 4.4: Proportion (%) of farmers with knowledge on potato bacterial wilt detection (N=81)
Table 4.5: Sources of information (communication media) on potato bacterial wilt detection (N = 81)
Table 4.6: Potato bacterial wilt disease detection criteria mentioned by farmers (N = 81)
Table 4.7: Proportion (%) of farmers with knowledge on spread of potato bacterial wilt.
Table 4.8: Sources of Information on spread of PBW
Table 4.9: Farmers’ knowledge of PBW control (N=81)
Table 4.10: Methods used by farmers to control bacterial wilt
Table 4.11: Proportion of farmers’ experience on incidences of bacterial wilt per season
Table 4.12: Reasons given by farmers behind seasonality of bacterial wilt incidences in their fields.
Table 4.13: Incidence of bacterial wilt in tubers per variety using Visual and DAS-ELISA methods
Table 4.14: Incidence of bacterial wilt in tubers per market using different methods.
xiiList of Appendices
Appendix I: Acronyms
Appendix II: Potato diseases- farmer questionnaire
Appendix III: Score Sheet for Incidences of Bacterial Wilt from Market Survey........... 57 Appendix IV: Plates
Appendix V: Analysis of Results
I.I Background Malawi population relies on maize as a staple food crop and tobacco as the cash crop. For the past decade, however, the maize production has been going down as a result of several factors.
Some of which are frequent droughts or drop in rainfall amounts, high cost of fertilizer, increasing rate of nutrient depletion, fluctuating and low selling prices which make farmers unable to meet higher cost of production. According to (FEWSNET/MALAWI May-June 2001), the production of maize went down by more than 30% in 2001 as compared to 2000, a trend which has been there for the last decade.