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Emerging disease challenges to sustainable production of Brachiaria grass in Rwanda

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Presented at the Annual Congress of Grassland Society of Southern Africa, Upington, South Africa, 30 June - 4 July 2019

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Emerging disease challenges to sustainable production of Brachiaria grass in Rwanda

  1. 1. Emerging Disease Challenges to Sustainable Production of Brachiaria Grass in Rwanda B. Uzayisenga, M. Mutimura, J. W. Muthomi A. W. Mwang'ombe & S. R. Ghimire Annual Congress of Grassland Society of Southern Africa Upington, South Africa 30 June - 4 July 2019
  2. 2. Introduction ▪ Agriculture is backbone of Rwanda ▪ Livestock contributes 3% of national GDP ▪ Low livestock productivity contributed mainly by limited pasture land, shortage of quality feeds especially in dry season, Napier grass diseases and climate change ▪ Brachiaria grass is the fodder promoted in Rwanda to alleviate livestock feed shortage ▪ Diseases are observed as an emerging challenge for Brachiaria production ▪ Very little known about Brachiaria diseases in Rwanda, and in SSA in general Njarui et al., 2016
  3. 3. Objectives ▪ To evaluate farmers’ knowledge on Brachiaria grass diseases ▪ To assess incidence, severity and distribution of Brachiaria grass diseases in Rwanda
  4. 4. Materials and methods Map showing locations of surveyed districts (Huye, Nyamagabe, Bugesera, Kayonza and Rwamagana) ▪ Five districts ▪ Two seasons: dry and wet ▪ Dry season: 25 fields ▪ Wet season: 75 fields ▪ Physical, agronomic and social data collection ▪ Social information: o Age o Gender o Marital status o Education level Survey for Brachiaria diseases
  5. 5. Materials and methods Assessment of Disease incidence and severity Information collection Farmer explains about his field 20 stools per field from four different quadrats
  6. 6. Materials and methods Table 1. Scale for scoring the severity of disease Disease Scale Reference Leaf blight 0 to 5 CIAT, 2004 Leaf spot 0 to 4 Stubbs et al., 1986 Rust 0 to 7 CIMMYT, 1985 Recording of disease incidence ▪ Observations of 20 stools from four different square meter quadrats ▪ Incidence was calculated as the percentage of the infected plants in comparison with all observed stools
  7. 7. Results District Av. age (yrs.) Gender (%) Marital status (%) Education level (%) Male Female Married Single Widow Primary Secondary Tertiary Huye 41.7 40.0 60.0 80.0 13.3 6.7 40.0 53.3 6.7 Nyamagabe 50.2 80.0 20.0 66.7 26.7 6.7 40.0 53.3 6.7 Bugesera 45.5 60.0 40.0 100.0 0.0 0.0 93.3 6.7 0.0 Rwamagana 48 60.0 40.0 100.0 0.0 0.0 93.3 6.7 0.0 Nyagatare 46.1 61.5 38.5 92.3 7.7 0.0 69.2 23.1 7.7 Mean 46.3 60.3 39.7 87.7 9.6 2.7 67.1 28.8 4.1 Characteristics of farmers interviewed during Brachiaria disease survey
  8. 8. Results District Disease Yield loss Free Present Below 5% 25-50% Huye 80.0 20.0 0.0 20.0 Nyamagabe 80.0 20.0 0.0 20.0 Bugesera 40.0 60.0 40.0 20.0 Rwamagana 86.7 13.3 13.3 0.0 Nyagatare 73.3 26.7 26.7 0.0 Mean 72.0 28.0 16.0 12.0 Farmer knowledge on Brachiaria diseases & impact of diseases on forage production
  9. 9. Results Farmer knowledge on disease symptoms Symptoms Districts Total Huye Nyamagabe Bugesera Rwamagana Nyagatare Bad growth 0.0 0.0 6.7 0.0 0.0 1.3 Drying of leaves 0.0 0.0 0.0 6.7 0.0 1.3 Holes on leaves 0.0 0.0 0.0 0.0 6.7 1.3 Yellowing of leaves 0.0 6.7 53.3 6.7 20.0 17.3 Yellowing & drying of leaves 13.3 13.3 0.0 0.0 0.0 5.3 Do not know 86.7 80.0 40.0 86.7 73.3 73.3 Total 100.0 100.0 100.0 100.0 100.0 100.0
  10. 10. Results Diseases recorded in survey Leaf spot Rust Ergot Virus like Leaf blight
  11. 11. Results Fig.1. Prevalence of major diseases B. Prevalence of rust c. Prevalence of leaf spot A. Prevalence of leaf blight
  12. 12. Results Fig.2. Incidence of major diseases in dry season 0 10 20 30 40 50 60 70 80 90 100 Huye Nyamagabe Bugesera Rwamagana Nyagatare Diseaseincidence(%) Districts Leaf blight Rust Leaf spot a a a a c b c b b b b c b b c
  13. 13. Results Fig.3. Incidence of major diseases in wet season - 10 20 30 40 50 60 70 80 Huye Nyamagabe Bugesera Rwamagana Nyagatare Diseaseincidence(%) Districts Leaf blight Rust Leaf spot d a b c a a b ab a c b b d d c
  14. 14. Results Fig.4. Severity score of major diseases in dry season 0 0.5 1 1.5 2 2.5 Huye Nyamagabe ` Bugesera Rwamagana Nyagatare Diseaseseverityscore Districts Leaf blight Rust Leaf sport b c c b b b b c b b a a aa c
  15. 15. Results Fig.5. Severity score of major diseases in wet season 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Huye Nyamagabe ` Bugesera Rwamagana Nyagatare Diseaseseverityscore Districts Leaf blight Rust Leaf sport b a a a b c b b a b b c c c c
  16. 16. Conclusion and recommendations Rust spore collection ▪ Leaf blight and rust were found widespread in all surveyed districts ▪ The incidence was 55.6% and 45.7%; 30.6% and 32.6% for leaf blight and rust respectively ( dry and rainy seasons) ▪ Leaf blight, leaf spot and rust were found as major Brachiaria diseases in Rwanda ▪ Identification of associated causal agents and evaluation of disease management options are high priority for sustainable management of Brachiaria diseases
  17. 17. Acknowledgement ▪ The BecA – ILRI ▪ The Swedish International Development Cooperation Agency (Sida) ▪ University of Nairobi ▪ Supervisors: Prof. James W. Muthomi, Prof. Agnes W. Mwang’ombe, Dr. Mutimura Mupenzi, and Dr. Sita R. Ghimire. ▪ Rwanda Agriculture and Animal Resources Development Board ▪ Farmers in surveyed districts ▪ GSSA Conference organizers
  18. 18. Thank you

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