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- 6 - Agriculture, Food and Veterinary Sciences
- Submitting institution
- University of Greenwich
- Unit of assessment
- 6 - Agriculture, Food and Veterinary Sciences
- Summary impact type
- Health
- Is this case study continued from a case study submitted in 2014?
- No
1. Summary of the impact
Onchocerciasis, caused by a nematode worm, leads to morbidity ranging from skin disease to bilateral blindness in 37,000,000 people globally, with rural communities the most at risk. In the island of Bioko, Equatorial Guinea, infection control measures with a drug were not succeeding until research by Prof. Cheke, University of Greenwich, underpinned the design and implementation by WHO of an insecticidal control campaign to eliminate the disease’s insect vector. This resulted in health, economic and agricultural productivity benefits such as the gross value added to the economy by agriculture increasing from 1.9% in 2015 to 2.3% in 2020 and 350,000 people were free of onchocerciasis by 2017.
2. Underpinning research
Onchocerciasis, caused by the nematode worm Onchocerca volvulus and transmitted by blackflies ( Simulium spp.), affects millions of people globally. Since 1979 Professor R. A. Cheke (Pest Behaviour Group, Natural Resources Institute, which joined University of Greenwich in May 1996) has conducted research on the taxonomy, behaviour, ecology, vector status and control of blackflies in West Africa and elsewhere. Initially, he researched entomological problems encountered by the WHO Onchocerciasis Control Programme in West Africa (OCP; terminated in 2002, but continued with Special Intervention Zones until 2007), involving studies on different members of the Simulium damnosum complex (the vectors in most of sub-Saharan Africa). Thus, Cheke had the necessary experience to conduct research that underpinned the elimination of onchocerciasis vectors from Bioko island in 2005 [ 3.6], as part of an international team coordinated by the WHO African Programme for Onchocerciasis Control (APOC), an organisation formed to deal with onchocerciasis in countries that were not participants in the OCP. APOC produced a film about the Bioko elimination and a similar event in Uganda ( https://www.youtube.com/watch?v=ba-OKhQQ9k8).
APOC sponsored visits to the island by Cheke, M.D. Wilson (project leader, University of Ghana) and collaborators including B. Tele (OCP, insecticide susceptibility tests), R. Meyer (ex OCP, Hamburg, Germany, insecticide applications) and R. J. Post (Natural History Museum, cytotaxonomy), to work in liaison with A. Sima of Equatorial Guinea’s Ministry of Health and Social Welfare. Cheke was responsible for vector surveys and onchocerciasis transmission estimates. Meyer and Cheke designed the control scheme by mapping and marking field sites targeted for control. They conducted insecticide trials, following susceptibility tests by Tele, using only ground-based applications. Concurrently, they devised a programme for monitoring fly numbers and infection rates that was fully operational in 2001.
After the success of the ground-based control trials, the results were reported to APOC in March 2001 and an APOC meeting held in May 2002 recommended a vector control programme. APOC then instigated helicopter-based control combined with ground treatments in 2003. This attempt was unsuccessful because some vector breeding sites in irrigation channels were not treated, despite their locations having been reported by Cheke in 2001. Nevertheless, a second control programme in 2005 succeeded in eliminating the vectors.
Examples of Cheke’s research that underpinned the impact by contributing directly to the success of the control campaign were: (i) confirmation that only one vector taxon was present [ 3.4]; (ii) description of this vector as a new form [ 3.5]; (iii) estimates of its vectorial efficiency [ 3.3]; (iv) delimitation of its geographic distribution for selection of insecticide treatment sites, in a vector elimination plan proposing targeting the vector’s more restricted range during dry seasons [ 3.2], after (v) trials of insecticides, testing the feasibility of such controls with ground-based trials, and ascertaining that elimination would be impossible without aerial control support due to areas of rugged terrain [ 3.2].
The anti-vectorial campaign was conducted in conjunction with mass drug administration (MDA) of ivermectin. O. volvulus worms reproduce by releasing offspring (microfilariae), which cause the pathology and are ingested by the vectors. Although these microfilariae can be killed by the drug ivermectin, there was no registered macrofilaricide that could kill the adult worms which live for up to 12 years. As there are contra-indications for chemotherapy with ivermectin in onchocerciasis patients co-infected with the eye-worm Loa loa, it was instructive that proven vectors of L. loa were identified on Bioko by Cheke during his field work on onchocerciasis [ 3.1]. This was a timely warning as autochthonous transmission of the disease was demonstrated in 2017 by Priest & Nutman and later confirmed in 2018 by Ta et al.
3. References to the research
Cheke, R. A., Mas, J. & Chainey, J. E. (2003) Potential vectors of loiasis and other tabanids on the island of Bioko, Equatorial Guinea. Medical & Veterinary Entomology 17: 221-223. https://doi.org/10.1046/j.1365\-2915.2003.00436.x
Cheke, R. A., Meyer, R.R.F., Barro, T., Mas, J., Sima, A. N., Abaga S. E., Noma, M., Sékételi, A.V. & Wilson, M. D. (2009) Towards the elimination of the Bioko form of Simulium yahense from Bioko: planning and insecticide trials. Acta Zoologica Lituanica 19: 132-141. https://doi.org/10.2478/v10043-009-0013-8 (available at https://bit.ly/3s0vasB\)
Cheke, R.A., Tirados, I., Mas, J., Geenan, P., Adjaru, J. M. M., Bouaha, J. L. A., Sima, A., Meyer, R. R. F. & Wilson, M. D. (2006) Onchocerciasis transmission by the Bioko form of Simulium yahense Vajime & Dunbar 1975 (Diptera: Simuliidae). Studia dipterologica. Supplement 14: 26-30. doi:3-932795-23-7 https://www.researchgate.net/publication/281162956_Onchocerciasis_transmission_by_the_Bioko_form_of_Simulium_yahense_Vajime_Dunbar_1975_Diptera_Simuliidae
Mustapha, M., McCall, P. J., Cheke, R. A. & Post, R. J. (2006) The blackflies (Diptera: Simuliidae) of Bioko (Republic of Equatorial Guinea) and the Gulf of Guinea with a description of the larvae of the ‘Pomeroy’ form of Simulium cervicornutum. Systematic Entomology 31: 611-620. https://doi.org/10.1111/j.1365-3113.2006.00330.x
Post, R. J., Flook, P. K., Millest, A. L., Cheke, R. A., McCall, P. J., Wilson, M. D., Mustapha, M., Somiari, S., Davies, J. B., Mank, R. A., Geenen, P., Enyong, P., Sima, A. & Mas, J. (2003) Cytotaxonomy, morphology and molecular systematics of the Bioko form of Simulium yahense (Diptera: Simuliidae). Bulletin of Entomological Research 93: 145-157. https://doi.org/10.1079/ber2003228
Traoré, S., Wilson, M. D., Sima, A., Barro, T., Diallo, A., Aké, A., Coulibaly, S., Cheke, R. A., Meyer, R., Mas, J., McCall, P. J., Post, R. J., Zouré, H., Noma, M., Yameogo, L., Sékétéli, A. V. & Amazigo, U. V. (2009) The elimination of the onchocerciasis vector from the island of Bioko as a result of larviciding by the WHO African Programme for Onchocerciasis Control. Acta Tropica 111: 211–218. https://doi.org/10.1016/j.actatropica.2009.03.007
Key grants
Project Title “Onchocerciasis vector elimination project, Bioko, Republic of Equatorial Guinea”. WHO/World Bank African Programme for Onchocerciasis Control. Awarded to National Onchocerciasis Task Force Bioko, Ministry of Health and Welfare, Equatorial Guinea. External scientists’ team, including R.A. Cheke, led by Dr M. D. Wilson of Parasitology Unit, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana. Duration March 1999 – February 2002. Value: US$334,744 (£257,082).
4. Details of the impact
The existence of onchocerciasis on the island of Bioko and its detrimental effects on the health, well-being and socio-economic development of the island’s population required interventions. As a mass drug administration programme was not succeeding, research was conducted by a UoG researcher aimed at achieving control by elimination of the disease’s insect vector. Elimination of onchocerciasis transmission on the island of Bioko, Equatorial Guinea, in 2005 has now protected more than 350,000 people, especially since 2017 when the last adult worms within patients died. Freedom from onchocerciasis allowed communities to increase agricultural production to improve their livelihoods, with consequent benefits to health, agricultural productivity and the country’s economy.
UoG research enabled the island of Bioko to be free of onchocerciasis vectors. The impacts of the research not only had immediate effects after the successful control of the disease in 2005 but they also had accruing beneficial effects on human health and well-being, household income and agricultural productivity from then onwards. However, this could only be indisputably confirmed in 2017 due to the long-term nature of the infection. The adult worms responsible for the disease can live for up to 12 years, so those infected before the control campaign would retain morbidity until either they or the worms died. Therefore, the success of the vector elimination programme in 2005 could only be demonstrated unequivocally a minimum of 12 years after the intervention, i.e. by 2017 within the eligible impact period.
A study conducted in January and February 2014 found that 22% of 150 households in Bioko had at least one positive case of onchocerciasis [ 5.1, page 1022], whilst another study only detected one positive case in a sample of 543 people [ 5.6, page 14]. Further studies, also conducted in 2014, showed an overall seroprevalence of 7.9%, but, significantly, only in samples of individuals 10-years-old or older [ 5.3, page 1; 5.5, page 1]. This evidence showed that the vector control of 2005 had led to a permanent cessation of transmission. This conclusion was reinforced by a study in 2016-2017 that found no evidence of current infection or recent transmission and no evidence of onchocerciasis vectors, concluding that WHO serologic criteria for the cessation of MDA had been met [ 5.4, page 2]. At the time of these studies, the population of Bioko who had benefitted from the interventions since 2005 had reached 334,463 and the resulting health and well-being benefits would, amongst other improvements, have translated into an increase in productivity of agricultural workers.
Research by UoG resulted in agricultural economic growth in Bioko. Given that apart from detriments to life quality, onchocerciasis-infected farmers weed 34% less of fields than healthy farmers, the elimination of the vector in Bioko will have had similar economic and health impacts to those in the OCP area but on a proportionally smaller scale. In the OCP’s 11 West African countries economic benefits accruing from onchocerciasis control exceeded US$500,000,000, saving 640,000 disability adjusted life years (DALYs) per annum and adding 15,000,000 hectares of new land available for agriculture, benefits that were reviewed in 2019 [ 5.7]. Although disaggregated data separating Bioko from mainland Equatorial Guinea (Rio Muni) are unavailable, an indicator of impact relevant to Bioko since the vector elimination is the overall percentage of gross value added to the economy by agriculture, which had been 1.1% in 2010, increased from 1.9% in 2015 to 2.3% in 2020 ( http://data.un.org/en/iso/gq.html). Regarding crops grown on the island, data for Equatorial Guinea [ 5.2] show that gross values increased after 2005 and during the impact period after 2013 (Table 1). These data refer to Equatorial Guinea as a whole and include the mainland where onchocerciasis remains prevalent and where no onchocerciasis vector control took place (only MDA control), so the benefits on Bioko were probably higher than the reported numbers suggest.
Table. 1 Gross Production Values (constant 2014-2016 million US$) for Equatorial Guinea of crops grown on Bioko, including some requiring labour-intensive farming.
|| Year | % increase 2005-2018 | % increase 2013-2018 | | --- | --- | --- | --- | --- | --- | | Crop | 2005 | 2013 | 2018 ||| | Bananas | 12.37 | 14.61 | 15.94 | 28.9 | 9.1 | | Cassava | 17.31 | 21.52 | 23.95 | 38.4 | 11.3 | | Coconuts | 2.54 | 2.95 | 3.02 | 18.9 | 2.4 | | Plantains | 12.86 | 14.53 | 15.50 | 20.5 | 6.7 | | Sweet potatoes | 21.70 | 32.42 | 38.03 | 75.2 | 7.3 |
Another country adopts a strategy to control onchocerciasis developed by UoG researcher.
The demonstration that successful onchocerciasis control can be achieved by vector control in a delimited area such as Bioko has influenced strategies to control the disease elsewhere. For instance, the example of the control in Bioko [ 3.6] influenced advocacy for an insecticidal campaign along the Sanaga River in the Littoral Province and elsewhere in Cameroon [ 5.8, page 2; 5.10] and was used [ 5.9, ref. 18 on page 2; 5.11] to underpin a plan published in 2019 for a DFID-sponsored programme combining MDA using a novel macrofilarial drug (doxycycline) with vector control, also in Cameroon. This plan is being implemented in the South West Province of Cameroon, an area with loiasis co-endemicity, where MDA with ivermectin has been proceeding for 12 years yet onchocerciasis persists with a higher than expected prevalence and intensity.( https://countdown.lstmed.ac.uk/sites/default/files/centre/CS.%202.%20Implementing%20Alternative%20Strategies%20for%20Oncho%20Control.pdf). The Non-Governmental Organization Sightsavers stated that the “demonstration that river blindness control can be achieved through focal vector elimination has had impact wider than just Bioko, as it has informed strategies to combat river blindness elsewhere” [ 5.11, page 2] and regarding control on the Sanaga River the Yaoundé Initiative Foundation stated that “The lasting impact of this success is reflected by the continuation of this vector control programme in Cameroon over a limited length of the Sanaga river, thereby protecting farmers and allowing them to increase their productivity” [ 5.10, page 2].
5. Sources to corroborate the impact
Barroso, D.G., Moya, L., Herrador, Z. et al. (2018) Spatial clustering of onchocerciasis in Bioko Island, Equatorial Guinea. The Journal of Infection in Developing Countries 12: 1019-1025 . https://doi.org/10.3855/jidc.10159
FAO (2021) FAOSTAT: Crops. http://www.fao.org/faostat/en/#data/QV (accessed 12 February 2021).
Hernández-González, A., Moya, L., Perteguer, M.J. et al. (2016) Evaluation of onchocerciasis seroprevalence in Bioko Island (Equatorial Guinea) after years of disease control programmes. Parasites & Vectors (2016) 9: 509. https://doi.org/10.1186/s13071-016-1779-8.
Herrador, Z., Garcia, B., Ncogo, P. et al. (2018) Interruption of onchocerciasis transmission in Bioko Island: Accelerating the movement from control to elimination in Equatorial Guinea. PLoS Neglected Tropical Diseases 12(5): e0006471. https://doi.org/10.1371/journal.pntd.0006471.
Moya, L., Herrador, Z., Ta-Tang, T.H. et al. (2016) Evidence for suppression of onchocerciasis transmission in Bioko Island, Equatorial Guinea. PLoS Neglected Tropical Diseases (2016) 10: e0004829. https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004829
Ta, N., Moya, L., Nguema J. et al. (2018) Geographical distribution and species identification of human filariasis and onchocerciasis in Bioko Island, Equatorial Guinea. Acta Tropica 180: 12-17. https://doi.org/10.1016/j.actatropica.2017.12.030
Turner, H.C., Walker, M., Pion, S.D.S. et al. (2019) Economic evaluations of onchocerciasis interventions: a systematic review and research needs. Tropical Medicine & International Health 24:788-816. https://doi.org/10.1016/j.actatropica.2017.12.030
Che, J.N., Baleguel, P.N., Baleguel, P.D. et al. (2017) River blindness – A neglected disease transmitted by blackflies ( Simulium spp.). Outlooks on Pest Management August 2017: 1-4. https://international-pest-control.com/river-blindness-neglected-disease-transmitted-blackflies-simulium-spp
Wanji, S., Nj, T.M., Hamill, L. et al. (2019) Implementation of test‑and‑treat with doxycycline and temephos ground larviciding as alternative strategies for accelerating onchocerciasis elimination in an area of loiasis co‑endemicity: the COUNTDOWN consortium multi‑disciplinary study protocol. Parasites & Vectors (2019) 12: 574. https://doi.org/10.1186/s13071-019-3826-8
Testimonial, Feb 2021 - Prof Graham Matthews, Technical Director, Yaounde Initiative Foundation (Cameroon, UK). G.A. (2021)
Testimonial, Feb 2021 – Dr Louise Hamill, Global Technical Lead, Onchocerciasis and LF Sightsavers (UK)
- Submitting institution
- University of Greenwich
- Unit of assessment
- 6 - Agriculture, Food and Veterinary Sciences
- Summary impact type
- Environmental
- Is this case study continued from a case study submitted in 2014?
- No
1. Summary of the impact
Cassava provides more than half of daily dietary requirements for over 450 million farmers and their households in Sub-Saharan Africa (SSA) but is affected by two major viral disease epidemics. Strategic research at the University of Greenwich aimed to control the epidemics and sustain the food production and livelihoods of millions of people. For farmers, our research on curing cassava varieties from viral infections and identification of resistant varieties has contributed to reduced disease incidences and increased cassava production in the five worst affected countries in SSA (Kenya, Malawi, Mozambique, Tanzania, and Uganda). This also led to new enterprise activities for farmers through producing and selling high quality seed and at the policy level, our research has informed the Tanzania Seed Act amendment by developing the first cassava seed system in Tanzania, and this was replicated in Rwanda and Burundi.
2. Underpinning research
Cassava ( Manihot esculenta) is a tuberous climate-resilient starchy root and a vital source of food and income for over 450 million people in SSA. This is more so the case during extreme weather conditions when all other crops fail and thus it is an important source of household food security as well as a significant avenue for family income, particularly women farmers. However, two viral diseases, cassava mosaic disease (CMD - caused by cassava mosaic begomoviruses or CMBs), and cassava brown streak disease (CBSD - caused by cassava brown streak ipomoviruses or CBSIs), have severely affected cassava production. A pandemic of CMD that began in the 1990s and a new epidemic of CBSD from mid 2000s has affected cassava farmers in 11 SSA countries. CMD is estimated to cause annual losses between US$ 1.2-2.4 billion while CBSD causes losses up to US$750 million. This is because farmers cannot protect their crop against these diseases as they cannot afford expensive pesticides. Using healthy planting material of the disease-resistant cassava varieties is therefore the only sustainable way for controlling the two cassava diseases in Africa.
The University of Greenwich’s Natural Resources Institute (NRI) has been at the forefront of managing both CMD and CBSD for over three decades. The most recent research has been led by Professor Maruthi M N Gowda (referred to in journal references as Maruthi, MN), and together with a team of researchers ( Hillocks, Bouvaine, Tomlins and three PhD students) he has developed highly reliable diagnostic polymerase chain reaction (PCR) techniques for the accurate diagnosis of CMBs and CBSIs [ 3.1]. PCR is a highly accurate forensic technique that can detect the presence of virus infection in any infected samples (e.g., used for detecting Coronavirus in humans). PCR was highly useful for us to separate the virus-infected cassava plants from healthy ones. Our new protocols were high throughput, reliable and more efficient (between 50 to 300%) compared to existing methods for detecting the cassava viruses [ 3.2]. Tomlins led the EU funded CassavaGmarkets project, which part funded this work. Bouvaine and Hillocks were involved in the supervision of three PhD students (Abarshi, Mohammed, Otti) that contributed to diagnostic work and Hillocks also provided field expertise on cassava diseases.
In addition, Gowda used chemo- and thermo-therapy treatments and tissue culturing procedures for eliminating virus infections from cassava plants [ 3.3]. The use of chemo- and thermo-therapy kills virus particles in infected plant tissues (similar to killing cancer cells in humans), which are then regenerated by tissue culturing of treated tissues. Gowda then used PCR for confirming the absence of viruses in the treated tissues and plants. All this was achieved in the Bill and Melinda Gates Foundation (BMGF) funded project ‘ 5CP’ (2012-2016), led by the International Institute of Agriculture (IITA) Tanzania. In this project, NRI was the only non-African partner and made crucial contributions by curing over 2500 plants belonging to 31 varieties from the two viral infections. This was highly significant as prior to our research, no regional effort was made to cure cassava to exchange cassava varieties between the five most affected countries (Kenya, Malawi, Mozambique, Tanzania and Uganda).
The research involved importing diseased cassava plants to NRI from the five countries and curing them from viral infections in the UK in 2012-2013 using our innovative chemo- and thermo-therapy protocols together with tissue culture and virus indexing by PCR tests. The virus-free, certified, clean, tissue-cultured cassava plants (2500) were generated and sent back to all five countries by July 2013 via the commercial partner Genotypic International Limited in Kenya (a commercial service provider for further multiplying tissue cultured cassava) [ 3.3, 3.4]. This facilitated the first ever regional exchange of improved cassava varieties by August 2014 between the aforementioned five eastern and southern African countries, and importantly provided the healthy planting material to many farmers for cultivation. “NRI had a pivotal role to play in this effort… to clean cassava from virus infections… and …this task was done outstandingly well” [ 5.1]. Apart from being a key pillar of the cassava disease removal strategy, the development of clean cassava was geared to bringing about many additional benefits for farmer household prosperity and local economies, as described in the impact section of this case study. Among the 31 varieties investigated, NRI has more recently also identified new sources of virus resistance using state of the art next generation sequencing technologies such as RNA-Seq [ 3.5] as well as using them in cassava breeding in Tanzania [ 3.6]. The implications of this for future impacts are that farmer-preferred cassava varieties resistant to both diseases will be developed quicker and thus minimize disease infections and increase food security of over 450 million people in Africa.
3. References to the research
Abarshi MM , Mohammed IU, Jeremiah SC, Legg JP, Lava Kumar P, Hillocks RJ, Maruthi MN, 2012. Multiplex RT-PCR assays for the simultaneous detection of both RNA and DNA viruses infecting cassava and the common occurrence of mixed infections by two cassava brown streak viruses in East Africa. Journal of Virological Methods 179: 176– 184. https://doi.org/10.1016/j.jviromet.2011.10. 020
Otti G, Bouvaine S, Kimata B, Mkamillo G, Kumar PL, Tomlins K, Maruthi MN, 2016. High throughput multiplex real time PCR assay for the simultaneous quantification of DNA and RNA viruses infecting cassava plants. Journal of Applied Microbiology 120: 13461356. https://doi.org/10.1111/jam.13043 [ REF2 Submission: Identifier 14252]
Maruthi MN, Whitfield C, Otti G, Tumwegamire S, Kanju E, Legg JP, Mkamilo G, Kawuki R, Benesi I, Mhone A, Zacarias A, Munga T, Mwatuni F, Mbugua E, 2019, A method for generating virus-free cassava plants to combat viral disease epidemics in Africa. Physiological and Molecular Plant Pathology 105:77-87 https://doi.org/10.1016/j.pmpp.20 18.09.002
Tumwegamire S, Kanju E, Legg JP, Shirima R, Kombo S, Mkamilo G, Mtunda K, Sichalwe K, Kulembeka H, Ndyetabula I, Saleh H, Kawuki R, Alicai T, Adiga G, Benesi I, Mhone A, Zacarias A, Nicosa N, Matsimbe SF, Munga T, Ateka E, Navangi L, Maruthi MN, Mwatuni F, Ngudo G, Mwangangi M, Mbugua E, Ndunguru J, Rajabu C, Mark D, 2018, The process and lessons of exchanging and managing in-vitro elite germplasm to combat CBSD and CMD in Eastern and Southern Africa. Food Security 10: 351-368 https://doi.org/10.1007/s12571 - 018 - 0779 - 2
Maruthi MN, Bouvaine S, Tufan HA, Mohammed IU, Hillocks RJ, 2014. Transcriptional response of virus-infected cassava and identification of putative sources of resistance for cassava brown streak disease. PLoS ONE 9(5): e96642.
https://doi.org/10.1371/journal.pone.0096642
- Masinde EA, Mkamillo G, Ogendo JO, Hillocks R, Mulwa RMS, Kimata B, Maruthi MN, 2017. Genotype by environment interactions in identifying cassava ( Manihot esculenta Crantz) resistant to cassava brown streak disease. Fields Crops Research 215: 39-48.
Major research grants and NRI leads:
Gowda. Great Lakes Cassava Initiative (GLCI) project, 2008-2012, funded by the Bill and Melinda Gates Foundation (BMGF), led by the Catholic Relief Services-USA in which NRI was a key partner, US$21.8 million. http://pqpublications.squarespace.com/the - great lakes - cassava - initia/
Gowda. New Cassava Varieties and Clean Seed to Combat CBSD and CMD (5CP), 20122017, funded by the BMGF, led by IITA-Tanzania, US$6.2 million. NRI was the sole nonAfrican partner in 5CP and led research on cleaning cassava from virus infections.
Gowda. Limiting the impact of cassava brown streak disease on smallholders, women and the cassava value chain (LimitCBSD), 2012-2016, African Union Commission (AUC), led by NRI, Euro0.78 million. https://www.nri.org/latest/news/2013/new - project - to - continue battle - against - cassava - disease
4. Details of the impact
The harm caused by cassava virus diseases in Sub-Saharan Africa (SSA) was considerable by the time the CBSD started spreading fast in the mid-2000s, as more than half of all cassava plants were already infected with CMD on an area of 3 million square kilometres. The two diseases together caused estimated annual losses of about USD3,000,000,000 (Thresh et al., 1997, African Journal of Root and Tuber Crops 2, 13-19; Hillocks and Maruthi, 2015, Food Chain 5, 116122) to some of the poorest people on the planet who depend on cassava for food and income, particularly during droughts. Through 5CP, we supplied virus clean and improved cassava varieties resistant/ tolerant to both diseases, which was the only sustainable way to control the epidemics. The impact of our research was felt at several levels.
NRI research benefitted farmers and cassava seed entrepreneurs in Tanzania. At the farmer level, the partners of 5CP, supported by NRI’s research, produced clean (virus-free) cassava varieties, and been given free to farmers and cassava seed entrepreneurs (CSEs) since 2014 in Tanzania. The 5CP went on to produce a total of 3,665,406 ‘breeders seed’ (first step in the development of a variety) of 10 cassava varieties by 2017 [ 5.1, 5.7-5.10 and the 5CP project final report].
This work of 5CP, ably supported by NRI through virus diagnosis, tissue culture and training, created awareness and high demand for healthy cassava seed by farmers desperate for good quality seed resistant to the two diseases devastating their livelihoods [ 5.1-5.3, 5.7-5.10]. This transformative impact on farmers, their households and communities were recognised by major donors such as the Bill and Melinda Gates Foundation (BMGF) and it led them to further fund two projects for commercialisation of clean cassava seed and development of a formal cassava seed system in Tanzania for the first time [ 5.7]. The BEST Cassava Seed Champion projects have already trained a total of 280 CSEs, which sold cassava seed to approximately 47,000 smallholder farmers by the end of 2019 growing season, and indirectly benefitted over 1,000,000 farmers and their households in 11 Regions in Tanzania alone [ 5.1, 5.7]. “All these benefits would not have been possible without the participation and capability of NRI to clean, virus index and introduction of cassava in 5CP. The economic and food security benefits of this work has been the greatest I have seen in my 40 years of work on cassava” [ 5.2].
The work also led to a change in the spending habits of Tanzanian farmers. The commercialisation of clean seed, and success of an entirely new market for it, demonstrated a historical behavioural change among Tanzanian farmers; the willingness to purchase healthy cassava seed from CSEs, where previously they relied solely on using their own seed for planting in the new season. This attests in the most meaningful way to the benefits to productivity and thus livelihoods they experienced first-hand from use of the improved cassava varieties [ 5.1, 5.2, 5.5]. “Yes, there is increasing behavioural change in cassava farmers and are willing to pay and buy cassava planting materials” [ 5.5].
Research conducted at NRI informed the amendment in the Tanzania Seed Act. At the policy level, our procedures for cleaning cassava from virus infections had the most significant impact as they became a key part of developing cassava seed systems and institutionalising safe cleaning procedures in Tanzania in 2017 [ 5.6]. They are also implemented in Rwanda and Burundi [ 5.5]. They were used in another objective of the 5CP project to inform an amendment to the Tanzania Seed Act (2017) that regulates cassava seed health. It made, for the first time, lab testing for viruses and tissue culturing compulsory for developing pre-basic and basic cassava seed (seed prior commercialisation) [ 5.6] (see Table 15, Page 5 of the Amended Tanzania Seed Act). This was the first example where detailed guidelines for cassava seed certification were formally appended to legislation anywhere in east and southern Africa. Similar updates to seed acts are being implemented in Rwanda and Burundi, supported by the IITA. “The progress achieved with NRI in improving seed health has now been transferred to Burundi, Rwanda and Eastern DRC, and is being recommended now Africa-wide” [ 5.1, 5.5].
The exchange of cassava germplasm between the five affected countries via 5CP in 2014 was also the first of its kind, providing access to the best cassava varieties available in the region to both farmers and researchers, although the impact has been greatest in Tanzania due to additional funding from donors (e.g., BEST Cassava). The varieties Mkumba and Tz130 developed in Tanzania, for example, are now found to be resistant to both diseases in Uganda and Malawi and are released as new varieties in both countries in 2019. Similarly, the varieties Orera and Eyope developed in Mozambique were found suitable for growing in Tanzania and these are now released for farmer cultivation since 2017. In other projects e.g., LimitCBSD (2012-2015) funded by the African Union Commission and led by Gowda, these improved varieties have been crossed with farmer-preferred local varieties. This has led to the development of new cassava varieties with increased resistance to both diseases. “These virus-resistant cassava varieties directly impact in the lives of nearly 70 million farmers in East, Central and Southern Africa regions” [ 5.3]. The upscale of all these activities was seen in the general increase in cassava production and revival of cassava production and industries [ 5.1, 5.5].
Impact by NRI research is further recognised by additional funded projects that create wider and continuing impact in African countries. Gowda’s research has created further wider impact as the successes achieved so far have led to additional investment from donors [ 5.3-5.5, 5.7]. Our clean cassava varieties are being used in the following projects on different aspects of cassava research and development:
NextGen cassava project phase I and II (2014-2022), funded by the BMGF, led by the Cornell University is using some of the NRI cleaned 5CP cassava varieties in their breeding program for rapid integration of desirable agronomic traits. This project has created continent-wide impact as it operates in the western, eastern and southern Africa [ 5.3].
African cassava whitefly project (ACWP) phases I and II (2014-2022), also funded by the BMGF, led by NRI is using 5CP cassava in their pre-breeding program for developing cassava resistant to whiteflies, which spreads both CMD and CBSD.
Action control CBSD - The International Fund for Agricultural Development and the United States Agency for International Development each funded a replica of the 5CP project in Rwanda and Burundi, and DR Congo in 2018, respectively. Their aim is multiplying and distributing the best 15 cassava varieties to farmers. These efforts have been replicating the success experienced in Tanzania in 5CP in the three new countries [ 5.5].
LimitCBSD (2012-2016) and DualCassava (2018-2021), both led by Gowda and funded by the African Union Commission have used the 5CP varieties in advanced research on gene mining for virus resistance using next generation sequencing technologies.
An impact of all these efforts is an overall 25% increase in cassava production in the eastern African countries from 23,900,000 tonnes in 2010 at the peak of the epidemics to 30,100,000 tonnes in 2018 (FAOStat, 2019) [ 5.3, 5.4]. “The famers who have accessed the improved varieties have indeed gained increased productivity which has resulted in food security and better incomes from the surplus roots” [ 5.5].
5. Sources to corroborate the impact
Testimonial 1 on NRI’s contributions in the 5CP Project and their impact provided by a 5CP project leader Dr James Legg from the Tanzania branch of the International Institute of Tropical Agriculture (IITA).
Testimonial 2 provided by Dr Geoffrey Mkamilo, the Director General of Tanzania Agricultural Research Institute, Dodoma.
Testimonial 3 provided by Dr Chiedozie Egesi, leader of the NextGen Cassava project, Cornell University.
NRI’s work impacting wider African countries is evidenced in Testimonial 4 given by Prof. Ibrahim Ahmad, Kebbi State University of Science and Technology, Nigeria of the wider implication of NRI’s research in West Africa.
Testimonial 5 provided by the 5CP project manager Dr Silver Tumwegamire from the Rwanda branch of IITA.
The amended Seed Act of Tanzania by the Government of Tanzania recommends lab testing and tissue culture plantlets (ideas came from NRI-developed protocols) for the first time for preventing CBSD spread as part of cassava seed act (see Page 5, Table 15).
The MEDA's Best cassava projects records their impact on cassava seed system. MEDA's BEST cassava projects; Tanzania | building an economically sustainable seed system for cassava in Tanzania (best cassava)
The IITA records the great progress made in the 5CP project https://www.iita.org/news- item/iita-led-5cp-project-reports-great-strides-regional-exchange-improved-cassava-
The IITA records the closing of the 5CP project and it's achievements https://www.iita.org/news-item/project-brings-ray-hope-fight-cassava-viruses-africa/
5CP received wider publicity in local and international Newspapers;
Tanzania: Cassava Disease Control Underway, August 1, 2016 | AllAfrica.com (South Africa)
- Submitting institution
- University of Greenwich
- Unit of assessment
- 6 - Agriculture, Food and Veterinary Sciences
- Summary impact type
- Environmental
- Is this case study continued from a case study submitted in 2014?
- No
1. Summary of the impact
Pinewood nematode (PWN) is a devastating disease of pine trees that was introduced into Portugal in 1999 and subsequently spread through 500,000 ha of forest despite EUR38,000,000 spent on attempted eradication. The nematode is spread by a beetle vector, and research by University of Greenwich academics led to development of a pheromone-based trapping system for the beetle that has significantly changed policy and practice for managing the disease and its vector throughout the EU. Early detection of the disease and control of the vector enabled by this system has contributed to preventing the spread of the disease into Spain and the rest of Europe. At least seven SME’s internationally have benefitted economically by commercialising the lures and traps and increasing business by millions of euros.
2. Underpinning research
The Chemical Ecology Group at the University of Greenwich’s Natural Resources Institute (NRI), has carried out research on pheromones and other semiochemicals affecting the behaviour of insect pests and development of their use in management of the pests from 1969 to the present (NRI joining the university in May 1996). The chemical structures of attractants for over 60 different species of insect pests or vectors have been identified and synthesised, and research by the Group contributed to the award of the Queen’s Anniversary Prize 2019 to NRI for development and implementation of innovative, “smart” methods of controlling pests and diseases.
The research included identification of pheromones of several cerambycid beetle species, and in 2007 the Group began a collaboration with Prof Juan Pajares, University of Valladolid, Spain, an expert on forest pests, particularly Monochamus galloprovincialis, the cerambycid beetle vector of pine wood nematode (PWN). The Spanish group had demonstrated that male beetles produced an aggregation pheromone attracting male and female beetles. In the research at NRI ( 3.1), volatiles were collected from male and female beetles and analysed by gas chromatography coupled to electroantennographic (EAG) recording from receptors on the beetle antennae, a technique pioneered by NRI. A male-specific compound elicited EAG responses from antennae of both female and male beetles This was identified as a novel structure using mass spectrometry, microanalytical techniques and comparison with synthetic standards in the large library of compounds built up previously at NRI. A route for synthesis of the compound was developed suitable for large-scale production, and the synthetic compound was shown to attract M. galloprovincialis beetles to traps in field tests in Spain ( 3.1).
This work was taken up by the EU REPHRAME project (2010-2014) involving Hall and Pajares and collaborators from five other European countries, China and the US. The attractiveness was shown to be greatly synergised by chemicals from the host plants and also kairomones produced by another beetle pest ( 3.2). Slow-release formulations for the pheromone and the synergists were developed by NRI ( 3.1), and the attractant system was patented in 2011 ( 3.3). Production of lures in Spain was taken up by SEDQ and Econex under licence and the trade name “Galloprotect”.
Further research was carried out to minimise the number of non-target insects attracted to the traps. This has included not only mechanical modification of the traps but also investigation of alternative synergists for the pheromone including volatile components of wood smoke which were identified and tested by NRI ( 3.4).
The compound identified as the male-produced aggregation pheromone of M. galloprovincialis was subsequently shown by NRI to be the pheromone of M. sutor, a potential new vector of PWN in Europe and Asia, (3.5), and lures and traps were optimised for this species (3.6). The compound was also identified as a pheromone component in three other species of Monochamus and shown to attract eight other Monochamus species world-wide, as described in over 30 publications by other researchers. These include the pheromone of M. alternatus, the main vector of PWN in Asia. The compound was given the trivial name “monochamol” by Canadian authors in 2012 and is widely used to bait traps to detect the presence of invasive species of Monochamus world-wide.
3. References to the research
Pajares, J.A., Álvarez, G., Ibeas, F., Gallego, D., Hall, D.R. and Farman, D.I. (2010). Identification and field activity of a male-produced pheromone in the pine sawyer beetle, Monochamus galloprovincialis. Journal of Chemical Ecology 36: 570-583 (DOI: 10.1007/s10886-010-9791-5)
Álvarez, G., Gallego, D., Hall, D.R., Jactel, H. Pajares, J.A. (2016). Combining pheromone and kairomones for effective trapping of the Pine Sawyer Beetle Monochamus galloprovincialis. Journal of Applied Entomology, 140:58-71 ( DOI: 10.1111/jen.12297)
Pajares, A.J.A. and Hall, D.R. 2011. Attractant bait for capturing the Coleoptera insect Monochamus galloprovincialis, the pine sawyer. PCT WO 2011/048246 A2. https://patentimages.storage.googleapis.com/78/f1/ca/c05d916782b506/EP2517561A2.pdf
Álvarez, G., Ammagarahalli, B, Hall, D.R., Pajares, J.A., Gemeno, C. (2015). Smoke, pheromone, and kairomone olfactory receptor neurons in males and females of the pine sawyer Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambicydae). Journal of Insect Physiology, 42:46-55. (DOI: 10.1016/j.jinsphys.2015.08.004)
Pajares, J.A., Gonzalo Álvarez, A., Hall, D.R., Douglas, P., Centeno, F., Ibarra, N., Martin Schroeder, M., Stephen A. Teale, S.A., Zhiying Wang, Z., Shanchun Yan, S., Millar, J.G. and Hanks, L.M. (2013). 2-(Undecyloxy)-ethanol is a major component of the male-produced aggregation pheromone of Monochamus sutor. Entomologia experimentalis et applicata, 149:118-127.** (DOI: 10.1111/eea.12113 )
Pajares, J, Alvarez G, Hall D, Ibarra N, Hoch G, Halbig P, Cocos D, Johansson H, Schroeder M. (2017) Attractants for management of the pine sawyer beetle Monochamus sutor, a potential vector of Bursaphelenchus xylophilus. Journal of Applied Entomology 141: 97–111 (DOI: 10.1111/jen.12320)
Research grants:
G1: Prof Hugh Evans, Forest Research; David Hall; Co-I; Development of improved methods for detection, control and eradication of pine wood nematode in support of EU Plant Health Policy (REPHRAME); European Union Seventh Framework Programme FP7; March 2011 – November 2014; £2,700,000
G2: Rick Mumford, FERA; David Hall; Co-I; Tree Health and Plant Biosecurity Initiative: New approaches for the early detection of tree health pests and pathogens; BBSRC; April 2014-Mar 2017; £423,000
4. Details of the impact
Pine wood nematode (PWN) is the cause of a devastating disease of pine trees. It was introduced into Portugal in 1999 and subsequently spread throughout the country to 500,000 ha of forest. The disease is spread naturally by vector beetles of the Monochamus genus, and the only vector identified conclusively in Europe is M. galloprovincialis. In the absence of control measures, it was estimated that losses in Europe due to damage by the nematode would be of the order of EUR20,000,000,000 during the period 2008-2030 ( 5.1. p1).
Development of pheromone-baited traps for the vector M. galloprovincialis, resulting from this research by NRI and its partners, has changed policy and practice in the European Union (EU) to prevent spread of the disease and the subsequent economic losses, and also benefitted SME’s which have commercialised the patented trapping technology.
Impacts of the Research on Policy to Prevent the Spread of PWN in the EU
EU Regulations published in 2012 for dealing with new infestations of PWN required removal of susceptible trees within a radius of 500 m round infested trees and intensive manual surveys for PWN in susceptible trees in a buffer zone of 20 km beyond this. In the light of results of the REPHRAME research project ( 5.12. Testimonial 1) an EU Task Force reporting in 2016 ( 5.2) recommended the use of the pheromone baited traps to catch M. galloprovincialis beetles, followed by molecular analysis for presence of PWN ( 5.2. pp 9, 13, 25, 28, 31). Based on the availability and effectiveness of the pheromone traps and new, more accurate data on beetle flight derived from research made possible by these pheromone-baited traps, they proposed reducing the clear-cut zone to 100 m and the buffer zone to 6 km ( 5.2. p26). This greatly reduced the cost of the operation and loss of trees, and the trap network had the added benefit of reducing the populations of vector beetles, thereby reducing risks of spread ( 5.2. p31). In 2017, these recommendations were taken up by the EU via an EC Implementing Decision ( 5.3) . “ The semiochemical/trap system....is now used across Europe in line with EU policy and this ground-breaking research has made a major contribution to preventing the spread of PWN from Portugal into the rest of Europe” ( 5.12 Testimonial 1,2).
French policy on measures to prevent spread of PWN was summarised by ANSES -French Agency for Food, Environmental and Occupational Health and Safety, (2015) ( 5.4). “ Trapping the insect vector for the purpose of early detection of the presence of the nematode remains an essential part of the control strategy.”( 5.4. p34) “ This method of trapping insect vectors….is possible because the baits designed to capture them are available and operational” ( 5.4. p35).
A 2016 policy document from the Euphresco network of 70 organisations in more than 50 countries worldwide coordinating national phytosanitary research ( 5.4) laid out the optimal strategy for trans-national monitoring programme of Monochamus using pheromone-baited traps based on research in five European countries ( 5.5. Exec Summary p4).
In 2018, the European and Mediterranean Plant Protection Organization (EPPO), an intergovernmental organization responsible for cooperation in plant health within the Euro-Mediterranean region with 52 members, revised their “Standard” for control and eradication of PWN ( 5.6). This revision “ takes into account the availability of an effective pheromone/kairomone attractant for trapping it”. “Early detection of new outbreaks is a very important factor in determining the likelihood of eradication” ( 5.6. p504). “ Sampling should include...the use of traps containing a mixed pheromone/kairomone attractant, followed by testing of any trapped Monochamus species for the presence of B. xylophilus ( 5.6. p505).”
In 2017, the UK Forestry Commission Contingency Plan for PWN ( 5.7) introduced use of pheromone-baited traps for monitoring introduction of Monochamus beetles and PWN into the UK with over 15,000 sq km of conifer forest. The trapping approach is particularly important as trees are likely to be asymptomatic in the UK and hence infection is difficult to detect ( 5.7. p 25).
The European Food Safety Authority (EFSA) Plant Health Panel of Experts ( 5.8) advised “ the most efficient detection method is trapping” for detection of invasive species of Monochamus worldwide ( 5.8. p13).
Impacts of the Research on Practice to Prevent the Spread of PWN in the EU
An EU Report on the Situation in Spain (2016) ( 5.9) reported a network of pheromone-baited traps placed throughout the demarcated area was established for the surveys of trees by the Plant Protection Service Spain and Regional Authorities in controlling an outbreak area in As Neves, Galicia ( 5.9. p14; 5.12. Testimonial 2).
An EU Report on the situation in Portugal (2018) ( 5.10) detailed that since 2016, the survey of the vector had relied exclusively on multi-funnel traps baited with the specific pheromone, which are installed and managed by the Portuguese Institute of Nature and Forests Conservation (ICNF). Over 2,000 traps were installed in 2018 ( 5.10. p.13).
Economic Impacts of the Research
Impact on spread of disease. Use of pheromone traps to monitor and reduce dispersal of the vector and PWN is only part of an integrated programme that has prevented spread of the disease from Portugal throughout Europe. Thus, it is not possible to attribute savings in the forestry sector to this innovation alone. However, the importance of early detection meant that “ by the time pinewood nematode was detected in Portugal, over 500 000 ha were affected, and EUR38,000,000 was granted for an eradication campaign, which ultimately failed. In contrast, three isolated outbreaks of pinewood nematode in Spain were detected early and eradicated with expenditures of less than EUR5,000,000 ( 5.11. p10). Future impact can be expected wherever PWN is a threat, e.g. Australia ( 5.11).
Sale of lures and traps. Lures for Monochamus containing the pheromone identified by NRI are now sold by at least seven different companies, including one in the UK and two in Spain. SEDQ Spain stated that the development of Monochamus galloprovincialis dispensers with NRI and University of Valladolid has allowed them to expand their business portfolio in forestry with product sales at a European level worth EUR1,500,000 from 2013 to the present ( 5.12. Testimonials 3,4).
5. Sources to corroborate the impact
Soliman T, Mourits MCM, van der Werf W, Hengeveld GH, Robinet C, Oude Lansik AGJM. 2012. Framework for modelling economic impacts of invasive species, applied to pine wood nematode in Europe. PLoS One. 7(9):e455505. https://doi.org/10.1371/journal.pone.0045505
European Commission (2016) Report of the Task Force on the control of pine wood nematode in Portugal operating between November 2014 and October2015. Ref. Ares(2016)2889630 - 22/06/2016.
European Commission (2017) Commission Implementing Decision (EU) 2017/427 of 8 March 2017 amending Implementing Decision 2012/535/EU as regards measures to prevent the spread within the Union of Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle et al. (the pine wood nematode) (notified under document C(2017) 1482).
ANSES -French Agency for Food, Environmental and Occupational Health and Safety (2015) Evaluation of emergency measures to prevent the spread of the pine wood nematode within the European Union. ANSES Opinion Collective Expert Appraisal Report, Sept 2015.
EUPHRESCO (2018) Focusing on Monochamus spp., insect vectors of Bursaphelenchus xylophilus (MONOCHAMUS). http://doi.org/10.5281/zenodo.2223533
European and Mediterranean Plant Protection Organization (EPPO) (2018) PM 9/1 (6) Bursaphelenchus xylophilus and its vectors: procedures for official control. https://doi.org/10.1111/epp.12505
Forestry Commission (2017). Contingency Plan for the Pine wood nematode ( Bursaphelenchus xylophilus) and its longhorn beetle ( Monochamus spp.) vectors. 31pp
EFSA Plant Health Panel (EFSA PLH Panel), Bragard C et al. (2018). Scientific Opinion on the pest categorisation of non-EU Monochamus spp. EFSA Journal 2018;16(11):5435, 35 pp. https://doi.org/10.2903/j.efsa.2018.5435
European Commission (2016) Final Report of an Audit carried out in Spain from 17 October 2016 to 28 October 2016 in order to evaluate the situation and controls for Bursaphelenchus xylophilus DG(Sante) 2016-8803-MR; Ref. Ares(2017)1847284 - 06/04/2017.
European Commission (2018) Final Report of an Audit carried out in Portugal from 12 November 2018 to 23 November 2018 in order to evaluate the situation and control for Bursaphelenchus xylophilus. DG(Sante) 2018-6488Ref. Ares(2019)3624343 - 05/06/2019.
A. J. Carnegie, T. Venn, S. Lawson, M. Nagel, T. Wardlaw, N. Cameron & I. Last (2018): An analysis of pest risk and potential economic impact of pine wilt disease to Pinus plantations in Australia, Australian Forestry, https://doi.org/10.1080/00049158.2018.1440467
Testimonials: Professor Hugh Evans, Fellow of UK Forest Research and Coordinator of EU REPHRAME project; Dr Angel Sanchez, Head of Environmental Protection Services, Castilla y León, Spain; Dr Lidia Roura, Product Control and Regulatory Manager, SEDQ, Spain; Dr Diego Gallejo, Technical and R&D Manager, Econex, Spain.
- Submitting institution
- University of Greenwich
- Unit of assessment
- 6 - Agriculture, Food and Veterinary Sciences
- Summary impact type
- Technological
- Is this case study continued from a case study submitted in 2014?
- No
1. Summary of the impact
Cassava is critical to the livelihoods of 450 million poor people in Africa, but it is limited by many factors including toxicity, low productivity and lack of market opportunities. This case study builds on one submitted to REF2014 and describes the impact pathway and scale up from strategic research on cassava fresh root transformation to make safe, cheap and valued products for food and industrial use. Adaptive interdisciplinary research by the University of Greenwich on value chain scaling led to market-based solutions for cassava to be used as a diverse commercial/industrial commodity. More than 2,370,000 tonnes of cassava roots were mobilised in this impact period compared to 170,000 tonnes in the previous one, with gross income to smallholder farmers and processors of USD369,100,000 compared to an estimated USD30,000,000 in REF2014. Increased incomes were reflected in livelihood improvements, for example, in Nigeria wealth assets (items like radio, fan, generator and sewing machine) showed a significant increase in the beneficiary group in comparison with the control group. Women’s asset status improved more than men’s in some dimensions, narrowing the gap to men’s asset status.
2. Underpinning research
Cassava is a staple food crop for 450 million people in Africa. Its contribution to improving the livelihoods of poor people is limited by its perishability (typically 48hrs), toxicity associated with its cyanogen context, inadequate processing and lack of market opportunities. Farmers have low yields, which could be improved by adoption of higher yielding varieties and improved agronomic practices. There is a lack of knowledge regarding best practice in scaling value chain development for the cassava sector. A value chain in this context identifies the set of factors and activities that bring a basic agricultural product in the field (fresh cassava in this case study) to final consumption, where at each stage value is added.
Professor Andrew Westby and colleagues at the Natural Resources Institute (NRI) of the University of Greenwich have developed a world leading portfolio of strategic and adaptative interdisciplinary research supported by the Department for International Development and the European Union to support cassava value chain development in Africa.
Research prior to 2000 focussed on understanding mechanisms of cyanogen reduction during cassava processing. In the period since 2000, the NRI team have produced more than 50 scientific publications investigating issues supporting cassava value chain development.
Research focussed on the efficient and safe transformation of the perishable roots into shelf-stable products, such as high-quality cassava flour (HQCF) and improved forms of traditional processed products [3.2, 3.3, 3.4, 3a, 3b, 3c]. This included overcoming problems associated with mould growth and mycotoxin contamination of traditional products [3.1] with improved sun or artificial drying. Mycotoxins are produced by fungi and can negatively affect human health. Artificial drying needs to be fuel efficient and produce high quality products.
Appropriate quality management protocols were developed to support the production of high-quality and food safe products to meet market demands [3.3]. Complementary work was undertaken to support understanding of desirable consumer attributes through sensory evaluation studies [3.3]. DFID [3c] and EC [3d, 3e, 3f] funded further projects that provided the basis for value chain development.
Implementation of the first phase of the Cassava Adding Value for Africa (CAVA) project (the basis for the REF2014 case study) between 2008 and 2013 supported by the Bill and Melinda Gates Foundation (BMGF), provided the basis for interdisciplinary research to understand the processes of scaling up and scaling out smallholder inclusive and sustainable cassava value chains [3.5, 3.7]. This facilitated the impact of the second phase of the project (CAVA2; February 2014 to March 2019).
With over GBP4,000,000 in funding from the European Union in 2012 [3e, 3f], technologies and systems were developed to support cassava value chain development including new market opportunities to drive processed product adoption e.g. using spent cassava flour from brewing beer for snack foods [3.6] and utilisation of wastes from cassava processing.
3. References to the research
Wareing, P. W., Westby, A., Gibbs, J. A., Allotey, L. T. and Halm, M. (2001). Consumer preferences and fungal and mycotoxin contamination of dried cassava products from Ghana. International Journal of Food Science & Technology, 36(1), 1-10. ( https://doi.org/10.1111/j.1365-2621.2001.00419.x).
Sanni, L.O., Adebowale, A.A., Filani, T.A., Oyewole, O.B. and Westby, A. (2006) Quality of flash and rotary dried fufu flour Journal of Food, Agriculture & Environment Vol.4 (3&4): 74-78. ( https://doi.org/10.1234/4.2006.920).
Tomlins, K., Sanni, L., Oyewole, O. B., Dipeolu, A., Ayinde, I., Adebayo, K. and Westby, A. (2007) Consumer acceptability and sensory evaluation of a fermented cassava product (Nigerian fufu). Journal of the Science of Food and Agriculture, 87, 1949-1956. ( https://doi.org/10.1002/jsfa.2941).
Obadina, A.O., Oyewole, O.B., Sanni, L.O., Tomlins, K.I. and Westby, A. (2007) Identification of hazards and critical control points (CCP) for cassava fufu processing in South-West Nigeria. Food Control, 19,22-26. (doi: https://doi.org/10.1016/j.foodcont.2007.01.002).
Lamboll, R., Nelson, V., Posthumus, H., Martin, A., Adebayo, K., Alacho, F., Dziedzoave, N., Mahende, G., Sandifolo, V., Sanni, L., Abayomi, L., Graffham, A., Hillocks, R. and Westby, A. (2015) Practical lessons on scaling up smallholder-inclusive and sustainable cassava value chains in Africa. Food Chain, 5 (1-2). pp. 28-52. ( http://dx.doi.org/10.3362/2046-1887.2015.004).
Omidiran, A.T., Sobukola, O.P., Sanni, A., Adebowale, A-R. A., Obadina, O. A., Sanni, L.O., Tomlins, K. and Tosch, W. (2016) Optimization of some processing parameters and quality attributes of fried snacks from blends of wheat flour and brewers' spent cassava flour. Food Science & Nutrition, 4 (1). pp. 80-88. ( https://doi.org/10.1002/fsn3.255).
Lamboll, R., Martin, A., Sanni, L., Adebayo, K., Graffham, A., Kleih, U., Abayomi, L. and Westby, A. (2018) Shaping, adapting and reserving the right to play: Responding to uncertainty in high quality cassava flour value chains in Nigeria. Journal of Agribusiness in Developing and Emerging Economies, 8(1), 54-76. ( https://doi.org/10.1108/JADEE-03-2017-0036).
Key Research Grants
Westby (PI). Improved cassava chips processing to access urban markets. (DFID, R7580); Feb 2000 – Mar 2003; £258,671.
Westby (PI). Commercialization of cassava fufu processing in West Africa that maximises benefits to livelihoods. (DFID, R9495), Nov 1999 - Mar 2003; £231,394.
J. Graffham (PI). Cassava as an industrial commodity - Approaches for expanding markets. (DFID, R8268; R8432): Jan 2003 – Dec 2006; £267,310.
Westby (PI). Development of small/medium scale enterprise sector producing cassava based products to meet urban demand W Africa (Cassava-SMEs). (EC through NR International Ltd., code ZJ033): Jan 2003 – Dec 2006; £661,153.
K. Tomlins (PI). Improving the livelihoods of smallholder cassava farmers through better access to growth markets (CassavaGMarkets). (EC, DCI-FOOD-2012/290-635) May 2012 - May 2017; £ 2,334,075.
K. Tomlins (PI). Gains from losses of root and tuber crops (GRATITUDE). (EC, FP7-KBBE-2011-5; No: 289843) Jan 2012 – Mar 2015; £2,371,510.
4. Details of the impact
The first phase of the Bill and Melinda Gates Foundation (BMGF) funded Cassava Adding Value for Africa (CAVA) project formed the basis of a REF2014 case study. Smallholder inclusive value chains were established for High Quality Cassava Flour (HQCF) based on NRI’s strategic and adaptive research on cassava processing and market development. At the time of REF2014, the initiative had worked with an estimated 90,000 farmers mobilising 170,000 tonnes of cassava roots, with a gross value added to rural communities of USD33,000,000.
UoG research on value chain development significantly built on previous impact figures. In the second phase of CAVA **[** 5.11 ], from February 2014 to March 2019, the project team led by Professor Westby and Professor Adebayo from the Federal University of Agriculture, Abeokuta (FUNAAB), Nigeria worked with partners in Nigeria (FUNAAB), Ghana (Food Research Institute), Uganda (African Innovations Institute), Tanzania (Tanzania Food and Nutrition Centre) and Malawi (University of Malawi) to scale up and scale out value chain development initiated as described in the REF2014 impact case study with additional USD18,816,547 funding from BMGF. This scaling up and scaling out built on (a) new market/scaling assessments undertaken by NRI/partner teams, (b) lessons learned from the first phase of CAVA [3.5] and (c) NRI underpinning research [3.1, 3.7].
The amount of cassava roots mobilized and the gross income from its sale and processing was over tenfold more than in the last REF. In this period, CAVA focused on value chains for HQCF, chips, starch, ethanol, improved traditional products ( gari and fufu in Nigeria, agbelima in Ghana, makopa in Tanzania) and animal feed. This enabled a wider range of NRI research to be used (e.g. on traditional products [3.2, 3.3, 3.4]) and provided flexibility in implementation in complex environments [3.7]. In total, 2,371,865 tonnes of roots were purchased in the period April 2014 to March 2019 from farmers across all five countries (compared with 170,000 tonnes over a similar time period as for REF2014) of which more than 70% went to new value chains [5.1, 5.2]. Between April 2014 and March 2019, across all five countries, smallholder gross income from the sale of cassava roots was USD134,600,000 and processor gross income was USD234,500,000, giving a combined total of USD369,100,000, a tenfold increase (compared with USD33,000,000 in the REF2014 period) [5.1, 5.2].
Business models were tailored to the country, location and market context. Implementation plans were developed to enable both women and men to participate and benefit. For new value chains, 51% of roots were supplied by men and 49% by women, whereas in traditional value chains 61% were supplied by women and 39% by men [5.1]. For new value chains, the ratios of men and women supplying roots were similar irrespective of which product was processed. At project end, the number of direct beneficiaries across all five countries amounted to 153,738 (from project monitoring and evaluation records, [5.1, 5.2]. Allowing for an average family size of 5, it is estimated that 750,000 people would have benefitted from the project.
Farmers that adopted productivity enhancing technologies and supply management practices (lessons learned from CAVA Phase I [3.5]) saw an increase in income which enhanced their quality of life as well as their households. Adoption of productivity enhancing technologies (increasing yields) in response to value chain development was an important part of the project theory of change agreed with the BMGF [5.2]. Smallholder farmers adopted productivity-enhancing technologies that enabled them to increase their yields by 58-154% (dependent on country) in response to market demands [5.1, 5.2]. As a specific example, the Commissioner for Agriculture for Ogun State [5.3] provides a testimonial that indicates that root demand in his State has exceeded 270 tonnes/day and farmers have responded by increasing their yields by 60%. Based on project data on costs of production and yield, it was estimated a smallholder farmer in Ogun State would benefit from a 67% increase in gross income against someone using traditional practices [5.1].
There is evidence that beneficiaries engaged in the project increased their wealth, particularly women. For example, in Nigeria (Ajayi, 2019 [5.4]) the mean values of wealth assets (items like radio, fan, generator and sewing machine) showed a significant increase in the beneficiary group compared with the control group. There were also significant increases in some selected asset wealth of female headed household beneficiaries compared with non-beneficiaries in Nigeria. For example, possession of radio, television sets, fans and sewing machines has increased significantly more than those in the control group of female-headed households who did not participate in the project. Comparing women with men beneficiaries, women’s asset status improved more than men’s in some dimensions, contributing to narrowing the gender gap in some categories [5.1, Tables 4 and 5].
An independent study of >2,700 households by Boadu et al. (2020) [5.5] of CAVA’s work in Ghana, concluded that “ it raised participants’ annual income by an average of GHC981.71” (£124). “ This increase represents about 50.4% of the average annual income of non-CAVA respondents”. It was found that “ CAVA project participants were 23.1% more likely to have access to markets for their produce than were non-participants”. The study concluded that “ the CAVA project empowered women by increasing their level of income and participation in household decision-making regarding use of productive resources”.
UoG research contributed to reduced fuel usage and enhanced quality assurance. Innovations and processing technology improvements were important drivers in value chain development (building on research e.g. [3.2]), especially where they contributed to a reduction in the use of fuel and enhanced quality assurance; for example, current Nigerian drying technologies are significantly better than those at the start of CAVA (fuel usage reduced from 374 to 65 litres/ton of dried product; throughput increased from approximately 100kg/hour to around 330kg/hour of dried product and efficiency increased from 11% to 55%) (see [5.6]). An important feature of CAVA implementation was building the capacity of a local equipment manufacturer, making it possible to make these improvements in collaboration with him [5.6]. The manufacturer reports [5.6] that “ flash dryers based on this improved design have been exported to eight countries in Africa, with multiple sales in Nigeria including a contract of 40 units to the Nigerian Ministry of Agriculture through the Bank of Industry for use in SMEs.” Overall, 87 flash dryers were installed [5.1], with installations in Nigeria, Tanzania (e.g. Kapipa Millers Ltd, Tanzania producing 4 tonnes/day of flour [5.8]), Malawi, and Uganda (e.g Windwood Millers Ltd who process 10 tonnes/day of flour using roots from 1,000 farmers [5.9]). In Ghana, one locally-fabricated flash dryer and 21 bin dryers were installed [5.1].
UoG research (for example [3.1]) contributed to understanding the risks associated with poorly dried cassava and the importance of processing it safely, for example, to avoid mycotoxin contamination. Efficient sun-drying of smallholder farmer supplied roots was an important approach for producing high quality products for diverse markets. Sun-drying involves a lower capital equipment cost investment, allowing farmers themselves to engage in processing and so benefitting themselves from value addition. Sun-drying operations were used by 1,270 community processing groups in all five countries [5.1]. Many of the 569 small and medium scale enterprises who engaged in the project also used sun-drying because of the lower capital investment costs. Use of sun-drying accounted for 32.5% of the cassava roots mobilised by the CAVA Phase 2 project [5.1].
Supply of dried cassava chips or flour to the brewing industry in Uganda [5.7] was one example of how the use of sun-drying allowed resource poor farmers to benefit from access to new markets. In the 2014-2020 period, Uganda Breweries Ltd purchased 18,973 tonnes of cassava flour from 1,599 households for £5,571,098 [5.7]. One of the smallholder processors, Zaituna, is sure of the benefits [5.10], “ My livelihood has improved. I have enough skills and knowledge in managing cassava in many areas. I have managed to construct a better house, out of the sweat of CAVA. I get good money and I could buy animals. Through CAVA also, I managed to educate my boy up to university level.”
UoG’s work was recognised by a number of prestigious awards. For its contributions to the CAVA project, NRI was awarded the Times Higher Award for International Collaboration of the Year (2014), the Guardian University Award for Research Impact (2015) and the Queen’s Anniversary Prize for Further and Higher Education (2015-2016). The Queen’s Anniversary Prizes recognises outstanding work by UK colleges and universities that shows quality and innovation and delivers real benefit to the wider world and public through education and training. The Prizes are the highest national Honour awarded in UK further and higher education. Prizes are granted by The Queen every two years.
5. Sources to corroborate the impact
Cassava: Adding Value for Africa Phase II Project Completion Report (2019) ( https://www.nri.org/images/documents/CAVA2/Final_Narrative_CAVA2.pdf).
Ms Kate Lawyer, CAVA2 Program Officer, Bill and Melinda Gates Foundation.
Dr Adeola Odedina, Honourable Commissioner of Agriculture, Ogun State, Nigeria.
Ajayi (2019) CAVA2 Nigeria. Endline Evaluation Report. ( https://www.nri.org/images/documents/CAVA2/NG_CAVA2_Final_report1.pdf).
Boadu, P., Quaye, W., Yamoahm A-A,N., Agyeman and Akuffobea, M. (2020) CBMS-20035 Does addressing gender inequalities and empowering women improve development programme outcomes? Partnership for Economic Policy. https://portal.pep-net.org/public/project/20035
Mr Idowu Adeoya, Managing Director, Nobex Technologies International, Lagos, Nigeria.
Mr Joseph Kawuki, Agriculture Manager, Uganda Breweries Ltd, Uganda.
Ms Oliver Faustine Matemu, Managing Director, Kipipa Millers Ltd, Mwanza, Tanzania
Mr Jonathan Isaac Otim, Managing Director, Windwood Millers Ltd, Lira, Uganda.
Summers, G. (2019) Brewing up success: CAVA2 combines quality, training and technology for farmers and industry https://www.nri.org/latest/news/2019/brewing-up-success-cava2-combines-quality-training-and-technology-for-farmers-and-industry
Cassava Adding Value for Africa (Phase 2) website ( www.cava2.org).