Fossils bring insect control down to earth

Soft whitish powders formed from the fossils of tiny planktons that once lived in oceans, rivers and lakes can be ground and mixed with grain to kill insect pests. Known as diatomaceous earths (DEs), these powders have proven to be highly effective in a range of agro-ecological zones in Zimbabwe and Tanzania, protecting crops for more than eight months. The food security and income opportunities of many rural households in sub-Saharan Africa are seriously undermined by storage insect pests. Farmers in Tanzania and Zimbabwe who tested DEs found that they offered an effective alternative to chemical pesticides - whose safety and efficacy are increasingly questioned - and to traditional materials such as ashes, botanicals and sand, which give inconsistent results.

Project Ref: CPH35:
Topic: 5. Rural Development Boosters: Improved Marketing, Processing & Storage
Lead Organisation: Natural Resources Institute (NRI), UK
Source: Crop Post Harvest Programme

Contents:		Description
		Validation
		Current Situation
		Environmental Impact

Description

Research Programmes:

• Crop Post-Harvest Programme
• PACT Capacity Building Services Group (http://www.pactworld.org/) provided a small grant in 2006 to assess the effectiveness of the post-harvest learning alliances (PHILA) established in Tanzania and Zimbabwe.

Relevant Research Projects:

R7034: Grain storage pest management using inert dusts

[1] Agritex is now amalgamated with Department of Research and Specialist Services (DR&SS) into Department of Agricultural Research & Extension services (AREX)

R8179: Small-scale farmer utilisation of diatomaceous earths during storage

R8460: Post-harvest innovation: Enhancing performance at the interface of supply and utilisation

R8460 spawned the post-harvest alliances (Post-Harvest Innovation Learning Alliance, PHILA) in Tanzania and Zimbabwe. These on-going alliances of diverse post-harvest stakeholders, include farmers organisations and/or union, statutory agencies (i.e. in crop health, extension, food security, regulation), local government (e.g. district agricultural authorities), private sector players, research and educational agencies, and NGOs. Lists of members are available at:  http://www.nri.org/PHILA/partners/index.htm

Research Outputs, Problems and Solutions:

The Problem: The food security and income opportunities of many rural households in SSA are seriously undermined by storage insect pests. Presently many small-scale farmers rely on imported organo-phosphate based pesticides to protect stored grain, but farmers and various authorities are increasingly questioning the safety and efficacy of these chemicals. Other households, who use traditional materials such as ashes, botanicals and sand to control storage insect pests, are faced with inconsistent and often poor results.

The Research: To address this widespread problem CPHP funded a set of research projects from the mid-late 1990s to 2005, which focused on exploring the efficacy of the inert dusts known as diatomaceous earths (DEs). These projects established that DEs were efficacious as grain protectants in a range of agro-ecological zones in Zimbabwe and Tanzania; that the technology - both product and process - was readily usable by diverse smallholders in the multiple research locations; and that food stocks were successfully protected for periods of more than 8 months. The research trialled both imported commercial DEs and a few of the many local deposits of DE found throughout SSA. Although the latter will probably represent more economically sound (i.e. to the state) and financially viable (i.e. to business and to farmers) options in the longer run, further work is first required to establish and implement safety, extraction and processing protocols.

In addition to examining the hardware (i.e. the DE technology) and software (i.e. the skills and knowledge required to use the technology) issues, the research also explored organisational aspects of the respective country post-harvest systems ('org-ware'). Post-harvest alliances have been established in Zimbabwe and Tanzania to promote improved partnerships and to develop new ways of getting relevant technologies such as DEs into economic and social use.

The Outputs:

§         A safe and readily useable product, Diatomaceous Earth, for protecting and extending the storage life of household grain and other food products (prime output, R8179);

§         Enquiry methodology: working method for extension staff to identify and map the production and post-harvest needs and priorities of diverse rural communities, to better target those farmers and households for whom the DE technology is best suited (supporting output, R8179); and

§         Active post-harvest innovation learning alliances (PHILA) in Tanzania and Zimbabwe, comprising various stakeholders with interests in effecting food security and improved livelihoods amongst small-scale farmers, to better facilitate the out- and up-scaling of DEs, and other relevant post-harvest technologies (prime output, R8460).

Types of Research Output:

Major Commodities Involved:

Cereals (maize & sorghum) and pulses (beans & cowpeas) as food, seed and feed stocks where applicable.

There is potential for application to dried cassava and sweet potato chips, and all other grains. Use of DEs as a protectant may be of particular interest to the organic farming sector in SSA e.g. for use with cotton, vegetables etc.

Production Systems:

* Where the DE technology is limited by humidity and scale, the enquiry methodology and post-harvest learning networks are effectively cross-cutting and relevant to all production systems.

Farming Systems:

* Where the DE technology is limited by humidity and production scale, the enquiry methodology and post-harvest learning networks are effectively cross-cutting and relevant to all farming systems. 

Potential for Added Value:

Grain production systems.  The DE technology relates to protecting and extending the storage life of household grain and other food products. Value might be added were this technology part of a package of good practice aimed at optimising and building on benefits throughout the crop cycle and post-harvest sequences. 

Livelihood systems.  Although the prime focus of the enquiry methodology was on activities associated with the storage trial crop, its design included scoping the wider pattern of household livelihoods. It is thus specifically able to help extension staff identify the constraints faced by different poor households, and facilitate their efficient matching of the most appropriate available technologies to individual household needs and priorities. As such, it should add value to most technological options (i.e. hardware choice and good practice) put on offer by extension services. More importantly, it will enable extension staff to be more responsive to the demands of different households, and should therefore improve the capacity and quality of service provision itself. 

National Innovation Systems.  The learning alliance networks in Tanzania and Zimbabwe were established to facilitate new and better ways of working between key post-harvest stakeholders, with the aim of expediting the scaling-out and scaling-up of post-harvest innovations appropriate to the needs of poorer farmers. They were intended not simply to improve the sharing and adoption of existing ideas, but to create a framework within which institutional constraints could be identified and creatively addressed, adaptive management be encouraged, and local ownership of emerging solutions thrive.  

The contributions of the three outputs to these different systems are given below:

Validation

How the outputs were validated:

Esther compares her ash treatment (left) with DE treatment (right)

DEs proved extremely successful in both sets of trials, with the FMT farmers particularly impressed with the quality and quantity of grain safely stored for the duration of the storage season, especially when compared with some traditional practices (see picture).

The validation methodologies for conducting on-farm DE research were subsequently shared with and adopted by Zambian and Ugandan researchers.

Peer review of the research findings is evidenced by publication in the following internationally refereed journals:

a.      Stathers, T. E., Riwa, W., Mosha, R., Kitandu, L., Mgara, K., Kaoneka, B., Mvumi, B. M., Morris, M. (submitted) Do diatomaceous earths have potential as grain protectants for smallholder farmers in sub-Saharan Africa: the case for Tanzania? Crop Protection.

b.      Mvumi, B. M., Stathers, T. E., Golob, P., Giga, D. P. (2006) Penetration of Sitophilus zeamais Motchulsky through diatomaceous earth-treated bulk maize.  International Journal of Tropical Insect Science, 26, 1, 28-34.

c.      Stathers, T. E., Mvumi, B. M., Golob, P. (2002) Field assessment of the efficacy and persistence of diatomaceous earths in protecting stored grain on small-scale farms in Zimbabwe.  Crop Protection, 21, 10, 1033-1048.

d.      Stathers, T. E., Chigariro, J., Mudiwa, M., Mvumi, B. M., Golob, P.  (2002) Small-scale farmer perceptions of diatomaceous earth products as potential stored grain protectants in Zimbabwe.  Crop Protection, 21, 10, 1049-1060.

The validation of the enquiry tool took place in villages in three different districts, two in Tanzania and one in Zimbabwe. Participating households from different wealth groups were visited three times per year for up to three years, by members of the research team and local extension staff. Participatory assessments of the two learning alliances were undertaken at review workshops, nine months after their inception. A further assessment of their effectiveness is currently being undertaken.

Where the Outputs were Validated:

The efficacy of imported commercial DEs were validated in three AEZs in Zimbabwe (Buhera and Binga districts, and Harare), for two consecutive storage seasons (1998-2000), using maize, sorghum and cowpeas, under on-farm and on-station conditions. The latter included both researcher- and farmer-managed trials. Similar work was conducted in Tanzania, where the Larger Grain Borer (Prostephanus truncatus), a devastating pest of stored grains, is endemic. This work, carried out over three consecutive seasons (2002-2005), took place in three further AEZs (Dodoma, Manyara and Shinyanga regions), where different post-harvest practices prevailed. These trials included maize, sorghum and beans. The efficacies of DEs from local deposits were also validated in field trials in Zimbabwe and Tanzania, during the period 2003-2005.

RMTs were implemented by the research team, district extension staff and lead farmers. FMTs were implemented by female and male farmers from different wealth groups. The trials involved smallholder farmers, in predominantly rain-fed, semi-arid (and peri-urban) production systems.

The extension methodology, which was developed jointly by researchers and extension staff in Tanzania, was used in conjunction with the FMTs in Mlali village, Kongwa district, and Arri village, Babati district, over the period 2003 - 2005. It was also tested with farmers involved in the FMTs in Buhera district, Zimbabwe, 2004 - 2005. Its deployment provided researchers and extension staff alike with a better understanding of the diverse circumstances of the different farming households.

While the post-harvest learning alliances (PHILA) in Tanzania and Zimbabwe include a range of stakeholders operating at the respective national levels, district and sub-district activities were focused on two districts, selected for their contrasting characteristics, in each country: Singida and Manyoni district in Tanzania; and Binga and Buhera districts in Zimbabwe. Both PHILAs, which were launched early in 2005, are currently active.

Current Situation

Who are the Users?

DE technology: DEs remain as yet unregistered for general use in Tanzania and Zimbabwe. However as many as 300 farmers in five districts, in Tanzania and Zimbabwe have trialled the DEs, and are very keen - price issues aside - to continue using them. Many other local farmers and extension staff, who have witnessed the success of the trials, are also keen to use DEs. While communities in Kagera region (Tanzania) and Beitbridge region (Zimbabwe) have long been using DEs from local deposits, to treat stored commodities and whitewash their houses, respectively.

Dissemination of the project's findings led to DEs being included in research activities in Zambia and Uganda, and enquiries have also been received from researchers in India, Iran, South Africa and Mozambique.

Extension methodology: Following demonstration of the efficacy of DEs, and the success of the 'enquiry tool', which was developed by research and extension staff together, the DE technology and the associated extension methodology have now been incorporated into the post-harvest training of extension staff (>300 in Tanzania) and university students (242 undergraduate and 14 post-graduate students at the University of Zimbabwe).

Post-harvest alliances: The learning alliances (PHILA) in Tanzania and Zimbabwe continue to provide an information platform for their memberships, and also via the website (http://www.nri.org/PHILA/), for third parties. 37,000 visits from 65 countries were made to the website in its first year. A study of the effectiveness of the alliances, and specifically the level of member participation in network activities, is currently taking place.

Where the outputs have been used:

In Tanzania and Zimbabwe the use of imported commercial DEs is still limited to the designated research areas. Other researchers in Uganda, and a research-entrepreneur partnership in Zambia, are also trialling DEs from local deposits. DE use has already been widely promoted in Zambia as an all-purpose pesticide.

The following table indicates where the DE technology is currently, or was very recently, in use. 

Extension staff together with key staff from Plant Health Services and Post Harvest Management Services (Ministry of Agriculture, Food and Cooperatives), Tanzania, have developed considerable expertise in use of the extension methodology, and are working with the Natural Resources Institute, UK, to develop guidelines for wider promotion of the methodology. It is presently being used in Dodoma, Manyara and Singida regions in Tanzania. In Zimbabwe it has been used in Buhera district.

The two post-harvest alliances are nation-wide networks in terms of their respective memberships and membership activities. In addition the website is accessible internationally, and many people from other countries have visited it and downloaded material.

Scale of Current Use:

The scale of current imported DE use is given in the answers to questions 12 and 13 above. Given however, that while they are not officially registered for use in the two research countries, their distribution for general (i.e, outside research) use remains prohibited (and has not taken place), it is interesting that farmers who have used or witnessed their use are still clamouring for them. Price will doubtless influence their eventual usage and rate of spread, but while available commercial pesticides are found wanting by those farmers who can afford them, it seems highly probable that, once legally available, their usage will spread rapidly. This observation is underpinned by the positive response that DEs have generated amongst the public and voluntary sector extension staff, registration agency staff, and others, involved in the trials. The active interest and rapid follow-up by researchers and/or entrepreneurs in Zambia and Uganda further corroborates this view. Currently, Dorowa Minerals Limited in Zimbabwe has claims over the Zambezi Valley deposit and is mining the local DE on an experimental basis, for industrial purposes and there is keen interest to widen the product base to include grain protectants following the research findings.

There is also some evidence that individuals familiar with the research findings have made land claims in those areas where local DE deposits exist, in anticipation of future business opportunities (e.g. in Uganda).

Policy and Institutional Structures, and Key Components for Success:

In neither country have existing institutional arrangements (programmes, policies etc) greatly assisted the promotion and/or adoption of the DE technology. In Tanzania this was despite growing emphasis by government and donors on improved agricultural policy, sector development strategies and programmes etc; while in Zimbabwe the political and economic situation threw up a range of institutional constraints. It was these different but constraining scenarios that compelled the research team to seek new ways of making the respective post-harvest systems more responsive, and led to the setting up of the learning alliances. These alliances, together with the very responsive print and electronic media, particularly in Tanzania, have been the prime platforms for information sharing.   

In Tanzania it was the initial interest and perseverance of a senior staff member in Plant Health Services (Mr Riwa), which was key to promotion within the ministry [4]. While the core research team promoted the idea of early engagement with key stakeholders, it was this individual's authority and connections that ensured this happened. We draw attention to this as it is our repeated experience that engagement with existing institutional frameworks structures is often dependent on key individuals.

Mr Riwa's status helped ensure the engagement of his ministry colleagues (i.e. from Post Harvest Management Services; Extension Services; and the registration agency, TPRI), together with district-based agricultural staff, who now fall under local government. He was also instrumental in reviewing the current Plant Protection Act to specify registration procedures for natural products such as DEs. In Zimbabwe, the core research team member (Dr Mvumi) is based in the University. His efforts to link with the ministry [5] there were harder to make and maintain because of the economic environment. 

A study of agricultural service provision by PHILA members in Tanzania suggested that specific NGOs were more effective than current public services, in meeting farmers' needs. At the district level, and issues of coverage aside, such NGOs appear to be better geared up to developing requisite capacity. A parallel study in Zimbabwe was more favourable of the government service provider, AREX, and critical of the Zimbabwe Farmers Union. 

[4] Ministry of Agriculture, Food and Cooperatives (MAF&C), formerly Ministry of Agriculture and Food Security (MAFS), Tanzania.

[5] Department of Agricultural Research and Extension Services (AREX), Ministry of Agriculture

Environmental Impact

Direct and Indirect Environmental Benefits:

Potentially favourable impacts may derive from the increased awareness of service providers about the factors influencing the decision-making and actions of resource-poor farmers, be it during land preparation, fertility management, pest management, crop storage or marketing. Moreover improvements in the relationship between farmers and service providers should lead to more participatory development and promotion of appropriate, sustainable and acceptable pre- and post-harvest crop management practices.

Current misuse of organophosphate storage pesticides often puts users' and consumers' health at risk. Inappropriate pesticides such as Actellic 50 EC (liquid formulation) and livestock pesticides are being applied directly to stored food in Tanzania, because of lack of understanding by small-scale producers of the associated dangers. Unscrupulous traders and some extension staff may also be responsible for misinforming them. The dust formulations of organophosphate pesticides, widely used in Southern Africa on stored-grain, are also often applied incorrectly. Misuse of pesticides poses a threat both to human and livestock health and to the wider environment. Improved storage management practices (including use of DEs) would reduce post-harvest storage losses, minimise health and environmental risks, and could lead to more sustainable farming practices.

DE use is likely to diminish the synthetic pesticide use in storage of foods. DEs are inert, have extremely low toxicity to mammals, and are 'Generally Regarded As Safe' by the USA Environmental Protection Agency. The US Food and Drug authority has exempted DEs from requirements of fixed residue levels when added to stored grain.

DE deposits in Kagera (Tanzania) and Chemutsi (Zimbabwe) have been field-tested and shown to be effective. For mining of these deposits, environmental impact assessments (EIA) need to be undertaken by the respective companies who are interested in developing commercial DE products. In Zimbabwe, Zimbabwe Phosphate Ltd (ZimPhos) has undertaken preliminary EIA.  Similar preliminary investigations have been undertaken in Uganda by researchers.

Adverse Environmental Impacts:

Currently, local people in the vicinity of the Kagera DE deposits use the materials for protecting stored beans and cowpeas. Commercialisation of the DEs might create conflict with the communities and hence there is need for a good understanding of land tenure and other relevant local bye-laws to avoid conflict and optimise mutual benefits. Uncontrolled use of the local deposits might create environmental degradation, and exposure to crystalline silica in the deposits could negatively affect health of workers in the DE deposits if protective masks were not worn.

Coping with the Effects of Climate Change, or Risk from Natural Disasters:

Recurrent droughts and other adverse climatic events in sub-Saharan Africa, and especially southern Africa, increase the vulnerability and food insecurity of small-scale farmers. Soil productivity is also declining. Any strategies which promote cost-effective and safe storage of whatever food and seed grain is harvested, reduce the risk of subsequent food shortages. The enquiry approach moreover is aimed at increasing the 'demand' component in service delivery, at empowering producers to express their needs and priorities, and service providers to respond to these differentiated needs and priorities. Such an approach can be expected to increase the adaptive capacity of diverse producers, and their advisory system, and over time, increase their resilience. The post-harvest learning alliances should provide further underpinning of improvements in adaptive capacity amongst the institutional stakeholders; improved adaptive management practices being one of the outcomes of such alliances.

Relevant Research Projects, with links to the
Research for Development (R4D) web site
and Technical Reports:

R4D	Project Title		Technical Report
R5742	Management of Cynodon in animal draught tillage systems
R6306	Field trials for quality assurance for horticultural exports.
R6311	Improving the use of phosphine for small-scale fumigation of grain on farms
R6655	Zimbabwe: Moisture conservation through improved weed management in Savannah cropping systems.
R6658	Epidemiology and crop loss assessment of rice nematodes in West Africa.
R6684	Risk warning to farmers of Larger Grain Borer infestation and reduced pesticide treatment in maize stores		51 MB
R7034	Grain storage pest management using inert dusts
R7173	Cattle management practices in tsetse-affected areas
R7189	Cultivar competitiveness and interactions with on-farm seed priming for integrated weed management
R7229	Mycobacterium bovis infection of cattle and man in Tanzania
R7357	Quantifying costs and risk factors of Bovine Tuberculosis in Tanzania
R7359	The delivery of animal health services to the rural poor: a framework for analysis
	The Livestock and Poverty Assessment Methodology: A toolkit for practitioners
	Restocking and Poverty Alleviation. Perceptions and Realities of Livestock- Keeping Among Poor Pastoralists in Kenya
R7405	Development of weed management in maize-based cropping systems
R7440	The physiological basis for the effects of on-farm seed priming in tropical crops: interactions with seedbed physical conditions
R7452	Characterisation of the causal virus of pigeonpea sterility mosaic disease: a step towards attaining sustainability of pigeonpea production in the Indian subcontinent
R7465D	Development of an integrated pest management strategy for the control of eggplant fruit and shoot borer (Leucinodes orbonalis) in South Asia
R7473	De-centralisation of road administration
R7486	Development of IPM techniques for the control of Larger Grain Borer, and effective management of household food grain stocks in sub-Saharan Africa (2nd phase)
R7502	Optimising institutional arrangements for demand-driven post-harvest research, delivery, uptake and impact on the livelihoods of the poor, through public and private sector partnerships
R7566	Management strategies for maize grey leaf spot (Cercospora zeae-maydis) in Kenya and Zimbabwe. Main Report. Appendix 6.
R7568	Characterisation and epidemiology of root rot diseases caused by Fusarium and Pythium spp. in beans in Uganda. Main Report. Annex.
R7597	A low-cost haemoglobinometer as a decision support tool for bovine disease diagnosis in sub-Saharan Africa
R7856	Strengthening social capital for improving policies and decision-making in Natural Resources Management (NRM)
R7965	Promotion of integrated pest management strategies of major insect pests of Phaseolus beans in hillsides systems in eastern and southern Africa
R7987	Message in a Bottle: Disseminating Tsetse Control Technologies
R8022	Research on the incidence, economic importance and causal agent(s) of bovine cerebral theileriosis in semi-arid pastoral livestock systems in Ngorongoro, Monduli and Simanjiro District in Northern Tanzania
R8042	Integrated control of East Coast Fever constraining livelihoods of smallholder farmers in sub-Saharan Africa
R8151	Improving the livelihood of resource-poor goat farmers in Southern Africa through strategic drug and nutritional interventions against gastro-intestinal nematode infections.
	Goatkeepers Manual
	Goatkeepers Manual, 2nd edition
	Relative economic benefits of strategic anthelmintic treatment and urea-molasses block supplementation of Boer goats raised under extensive grazing conditions at Onderstepoort, Pretoria, South Africa
R8152	Dissemination of Animal Health Knowledge for Development of Landless Dairy Cattle Owners in the Peri-Urban Regions of Pondicherry, India
R8164	Applying benchmarking as a tool for irrigation management reform. Report. Manual.
R8179	Small-scale farmer utilisation of diatomaceous earths during storage
R8190	Technology transfer and promotion of ecologically-based and sustainable rodent control strategies in South Africa
R8191	Promoting improved crop establishment in semi-arid areas
R8197	Development and promotion of appropriate IPM strategies for smallholder cotton in Uganda. Main Report. Annex 1, Annex 2, Annex 3, Annex 4, Annex 5, Annex 6.
R8205	Characterisation of the causal virus of pigeonpea sterility mosaic disease: a further step towards attaining sustainability of pigeonpea production in the Indian sub-continent
R8208	Decision support for risk management strategies of tick-borne diseases within sustainable pastoral systems
R8213	Including the voices of the poor: developing a decision-making framework for livestock disease prioritisation and the uptake of animal health technologies by poor livestock keepers. a). Summary. b). Livestock disease prioritisation: listening to the voices of the poor
R8215	Increasing food security and improving livelihoods through the promotion of integrated pest and soil management in lowland maize systems
R8219	Improved access to appropriate farm inputs for integrated maize crop management by small-scale farmers in Embu and Kirinyaga Districts, Kenya
R8265	Improving household food security by widening the access of smallholder farmers to appropriate grain store pest management
R8281	Linking the demand for, and supply of, agricultural production and post-harvest information in Uganda. Main Report. Annex.
R8297	Development of private sector service providers for the horticultural industry in Kenya
R8304	Technical support for SME supplying pheromone-based pest control technologies in South Asia
R8316	Bean root rot disease management in Uganda
R8318	Decision support for endemic disease control in sub-Saharan Africa - private sector drivers for technology adoption by resource-poor farmers
R8341	Promoting adoption of integrated pest management in vegetable production
		Leaflet: Pest Promotion through the Cartoon Network.
R8349	Developing crop protection research promotion strategies for semi-arid East Africa (Kenya and Tanzania)
R8402	STEP tools to package and deliver information for local use
R8403	Promotion of IPM for smallholder cotton in Uganda
R8410	Increasing the Effectiveness of Research within NARO, Uganda
R8413	Technical support for SME supplying pheromone-based pest control technologies in South Asia
R8414	Promotion of bean pest IPM
R8417	Promoting adoption of integrated pest management in vegetable production through improved resources for Farmer Trainers
R8422	Improving farmer and other stakeholders' access to quality information and products for pre- and post- harvest maize systems management in the Southern Highlands of Tanzania.
R8424	Rodent management in Bangladesh
R8428	Communication and research promotional strategies East Africa
R8429	Linking supply and demand in Uganda phase 2. Main Report. Annex.
R8441	Rodent management in South Africa
R8452	Increasing food security and improving livelihoods through the promotion of integrated pest and soil management in lowland maize systems, Phase II
R8453	Promotion of an IPM strategy for maize grey leaf spot (GLS) in East Africa
R8460	Post harvest innovations: enhancing performance at the interface of supply and utilisation
R8481	Sustainable management of sterility mosaic disease
R8494	Tracking social capital outcomes and sustainability of local natural resources management (NRM) policies

For relevant research projects, with links to further information

Target Audiences for this content:

Crop farmers, Processors,