Field efficacy of hermetic and other maize grain storage options under smallholder farmer management

Household grain storage continues to be of paramount importance in improving food security in sub-Saharan Africa (SSA) where maize postharvest losses of 10-20 % are reported. On-farm trials to compare alternative solutions for reducing household maize storage losses were conducted in the 2014/15 and 2015/16 storage seasons in two contrasting agro-ecological zones in Hwedza district of Zimbabwe. A wide range of treatments including a commercial synthetic pesticide (Shumba super dust®1), unregistered but commonly used botanical pesticides (Aloe ash, Colophospermum mopane leaves, Eleusine coracana (rapoko) chaff, and Ocimum gratissimum), hermetic storage facilities (metal silos, GrainPro Super Grain Bags (SGB) IVR™, Purdue Improved Crop Storage (PICS) bags), and storage bags with pesticide incorporated into their fabric (ZeroFly® bags), were evaluated. The results demonstrated the superiority of hermetic storage facilities (PICS bags, SGBs, and metal silos) in suppressing insect pest build up, insect grain damage and weight loss in stored maize grain. A newly introduced synthetic pesticide on the Zimbabwean market, Actellic gold dust®, was also evaluated in the 2015/16 season and was found to be highly effective. The following grain storage technologies; hermetic metal silos, SGB bags, PICS bags, and Actellic gold dust® pesticide are therefore recommended for smallholder farmer use to reduce stored grain losses due to insect pests

Measuring the nutritional cost of insect infestation of stored maize and cowpea

Our understanding and prevention of postharvest losses are critical if we are to feed a growing global population. Insect infestation-related losses of stored commodities are typically considered only in terms of quantitative, physical weight loss. Insect infestation affects the nutritional value and some nutritional components are impacted more severely than others. We infested maize and cowpea grain with commonly occurring stored product insect pests, and mapped infestation levels against nutritional composition over a 4-to-6 month storage period to analyse how insect infestation relates to different macro- and micro-nutrient contents. Insect infestation decreased the carbohydrate content of the stored grains, causing a relative increase in the proportion of protein and fibre in the remaining grain, and moisture content also increased. Sitophilus zeamais preferentially fed in the floury endosperm of maize, resulting in more carbohydrate loss relative to protein loss. Conversely, Prostephanus truncatus consumed the germ and endosperm, disproportionately reducing the fat, protein, iron and zinc grain contents. Nutrients are distributed more homogenously within cowpea than in maize grains, but Callosobruchus maculatus infestation increased the relative protein, fat, iron and zinc to carbohydrate ratios. This indicates how the nutrient content of insect-infested stored grain depends upon the grain type, the infesting insect, and the infestation level. Insect infestation therefore has consequences for human nutrition beyond those of grain weight loss. Using data collected on the changing nutritional composition of grain over time, with and without insect infestation, we modelled the associations between infestation and nutritional quality to predict estimated nutritional losses that could be associated with consumption of insect-infested stored maize and cowpea

Effectiveness of grain storage facilities and protectants in controlling stored-maize insect pests in a climate-risk prone area of Shire Valley, southern Malawi

Shire Valley is one of Malawi's most vulnerable areas to climate change (CC). In addition to other impacts, CC is expected to affect storage insect pest status, and the efficacy of grain storage facilities and protectants. On-farm grain storage trials were therefore conducted in Shire Valley to assess the performance of storage facilities and grain protectants against storage insect pests. Eight smallholder farmers hosted the trials in Thyolo and Chikwawa districts. Seven grain storage treatments were evaluated for 32 weeks during two storage seasons: Neem leaf powder (NM), Actellic Super dust (ASD), ZeroFly® bag (ZFB), Purdue Improved Crop Storage bag (PICS), Super Grain Bag (SGB), hermetic metal silo (MS) and untreated grain in a polypropylene bag (PP). Insect pest populations and grain damage increased with storage duration and differed significantly between treatments (p 75%) at both sites. The hermetic MS, ZFB bags, ASD and NM treatments did not effectively protect grain from insect damage. High in-store mean temperature (35.6 C) and high initial grain moisture content (13.7%) may have negatively affected efficacy of some treatments and seed germination. Tribolium castaneum survival in the MS requires further investigation. The hermetic storage bags (PICS, SGB) can be recommended for long-term maize grain storage (>32 weeks) by smallholder farmers in Shire Valley and other similar climate change-prone areas in sub-Saharan Africa

Predicting Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) populations and associated grain damage in smallholder farmers’ maize stores: a machine learning approach

Prostephanus truncatus is a notorious pest of stored-maize grain and its spread throughout sub-Saharan Africa has led to increased levels of grain storage losses. The current study developed models to predict the level of P. truncatus infestation and associated damage of maize grain in smallholder farmer stores. Data were gathered from grain storage trials conducted in Hwedza and Mbire districts of Zimbabwe and collated with weather data for each of the sites. Insect counts of P. truncatus and other common stored grain insect pests had a strong correlation with time of year with highest recorded numbers from January to May. Correlation analysis showed insect-generated grain dust from boring and feeding activity to be the best indicator of P. truncatus presence in stores (r = 0.70), while a moderate correlation (r = 0.48) was found between P. truncatus numbers and storage insect parasitic wasps, and grain damage levels significantly correlated with the presence of Tribolium castaneum (r = 0.60). Models were developed for predicting P. truncatus infestation and grain damage using parameter selection algorithms and decision-tree machine learning algorithms with 10-fold cross-validation. The P. truncatus population size prediction model performance was weak (r = 0.43) due to the complicated sampling and detection of the pest and eight-week long period between sampling events. The grain damage prediction model had a stronger correlation coefficient (r = 0.93) and is a good estimator for in situ stored grain insect damage. The models were developed for use under southern Africa climatic conditions and can be improved with more input data for greater precision models to build decision-support tools for maize-based production systems

Field evaluation of hermetic and synthetic pesticide-based technologies in smallholder sorghum grain storage in hot and arid climates

Field evaluation of six grain storage technologies under hot and arid conditions (32–42 oC; rainfall < 450 mm/year) in two locations in Zimbabwe were conducted over two storage seasons. The treatments included three hermetic technologies (Purdue Improved Crop Storage bags, GrainPro Super Grainbags, metal silos); three synthetic pesticide-based treatments; and an untreated control, all using threshed sorghum grain. Sampling was at eight-week intervals for 32 weeks. Highly significant differences (p<0.01) occurred between hermetic and non-hermetic treatments regarding grain damage, weight loss, insect pest populations, and grain moisture content; with the hermetic containers exhibiting superior grain protection. Weight losses were low (<3%) in hermetic treatments compared to pesticide-based treatments (3.7 to 14.2%). Tribolium castaneum developed in metal silos, deltamethrin-incorporated polypropylene bags and a pesticide treatment containing deltamethrin 0.13% and fenitrothion 1% while Sitotroga cerealella developed in a pesticide treatment containing pirimiphos-methyl 0.16% + thiamethoxam 0.036%. Mechanisms of survival and development of these pests in the tested treatments and under similar climatic conditions need further elucidation. These hermetic technologies can be successfully used by smallholder farmers in developing countries as alternatives to synthetic pesticides for protecting stored-sorghum grain under hot and arid climatic conditions to attain household food security. To our knowledge, this is the first published study on modern hermetic storage of sorghum grain under typical smallholder storage conditions and involving stakeholders

Climate change in semi-arid Malawi: perceptions, adaptation strategies and water governance: original research

Climate change and variability are a threat to sustainable agricultural production in semi-arid areas of Malawi. Overdependence on subsistence rain-fed agriculture in these areas calls for the identification of sustainable adaptation strategies. A study was therefore conducted in Chikwawa, a semi-arid district in southern Malawi, to: (1) assess community's perception of a changing climate against empirical evidence, (2) determine their local adaptive measures, (3) evaluate the potential of irrigated agriculture as an adaptive measure in household food security and (4) challenges over access to available water resources. The study employed focus group discussions and key informant interviews to assess people's perceptions of climate change and variability and their desired interventions. To validate the people's perceptions, rainfall and temperature data for the period 1960-2010 were analysed. A participatory complete randomised experimental design in both rain-fed and dry season-irrigated conditions was conducted to assess a maize cropping system that would improve adaptation. The study established persistent declining yields from rain-fed production in part because of perennial rainfall failure. In response, the community has shifted its focus to irrigation as an adaptation strategy, which has in turn triggered water conflicts in the community over the control of the resource. Water legislation however fails to adequately provide for rules governing sharing of water resources between various stakeholders. This article therefore recommends development of an appropriate institutional framework that forms a strong basis for equitable distribution of water for irrigation in areas most vulnerable to extreme climate events - including droughts and floods

Blanket application rates for synthetic grain protectants across agro-climatic zones: Do they work? Evidence from field efficacy trials using sorghum grain

Many smallholder farmers in sub-Saharan Africa rely on synthetic pesticides for protecting stored-grain. Recommendations on use of these grain protectants are typically based on “blanket” application rates which are fixed rates that are not varied according to grain type, pest range or agro-climatic regions. There are numerous anecdotal reports of storage pesticide failure or reduced efficacy from farmers. Might rising global temperatures be a contributory factor? Smallholder farmers are responding by over-applying pesticides, increasing the application frequency or switching to non-recommended pesticides; leading to a pesticide treadmill. Trials to determine the efficacy and persistence of five commercially-available synthetic pesticides applied at manufacturer's recommended rates on stored sorghum grain under contrasting climatic conditions were conducted in Mbire (mean temperatures of 32–42°C and 30–50% rh) and Harare (18–32°C; 42–75% rh) districts in Zimbabwe. Grain samples were collected at 8-week intervals throughout a 10 month period in the 2014/15 and 2015/16 storage seasons. The samples were analyzed for insect grain damage, weight loss, total number of storage insects by species and grain moisture content. Results showed significant differences in the performance of treatments (p<0.001). Grain damage was consistently higher in Harare than in Mbire. Tribolium castaneum was the dominant pest in Mbire, while Sitotroga cerealella and Sitophilus oryzae were dominant in Harare. Tribolium castaneum populations were high in the Shumba Super dust⁠® (fenitrothion 1%+deltamethrin 0.13%) treatment in Mbire, while S. cerealella was dominant in Super guard⁠® (pirimiphos-methyl 1.6%+permethrin 0.4%) and Actellic Gold dust⁠® (pirimiphos-methyl 1.6%+thiamethoxam 0.36%) treated grain in Harare. Grain moisture content varied with ambient conditions, and was high in treatments with high insect pest levels. The results show that differences in climatic conditions influence insect pest species dynamics and response to pesticide treatments. Storage pesticides are not equally effective across different climatic conditions; thus more context-specific application recommendations are required

Reducing postharvest losses in the OIC member countries

It is universally understood that postharvest losses are high, particularly in less developed economies, and that this is an issue of keen interest to researchers, practitioners and policy makers alike. Postharvest losses are defined by COMCEC as food damage or degradation of food during different stages of the food supply chain that are incurred between the farm-gate and prior to retail and consumption. Highlights of this report. • Clear evidence of substantial postharvest losses across all Members and commodity groups and these are similar to those reported in non-OIC Member Countries. Figures are estimates though. • Pockets of high physical losses identified: e.g., fruit and vegetables, root and tuber crops and meat and meat products • High economic losses for cereals and fish and fish products • Nutrition losses were rarely reported but for cereals in Sub-Saharan Africa losses could be equivalent to the annual caloric requirement of 48 million people • Weak policy support to effecting loss reduction strategies almost universal • Limited on-going measurement of postharvest losses means impact of innovation and policy was hard to measure This analysis of postharvest losses in the OIC Member Countries, conducted by a team from the Natural Resources Institute (NRI), University of Greenwich between January and July 2016, sought to provide ways to contribute to reduced postharvest losses. The analysis sought to identify approach and practices, and policy recommendation for future investments. The methods used were a combination of a brief literature review, an on-line survey of key informants, and a series of commodity specific case studies that included three field visits. The scope of the study included all OIC Member Countries, all three official Regional Groups of OIC Member Countries (African, Asian and Arab), and representation from seven commodity groups (cereals, roots and tubers, oilseeds and pulses, fruit and vegetables, meat and meat products, milk and dairy products and fish and seafood). Field visits were conducted in Indonesia, Bangladesh and Oman. A conceptual framework was developed from knowledge of the literature and the challenges and complexities of measuring postharvest losses. The postharvest physical losses in OIC countries reported by commodity group for the literature review, online survey and case/field studies suggested that they were not that different from the global losses for each commodity that the authors extracted from FAO data. For cereals, root and tuber crops, oilseeds and pulses, fruit and vegetables, meat and meat products, milk and dairy products and fish and fish products, the extrapolated losses from FAO data was 12-15%, 22-34%, 15-38%, 11-12% and 16-25% respectively. Compared to this, the range found from the OIC study was 9-48%, 7-50%, 14%, 3-65%. 6-40%, 2-30% and 3-50% respectively. Although the spread is wider that the estimates from FAO reports, it is considered to be consistent. Thus the postharvest losses in OIC countries are not that different from elsewhere. Some commodities and countries are well covered (e.g. maize in Uganda), but most are poorly analysed in existing research, with some significant knowledge gaps identified (e.g., some countries with little or no literature, other commodities under researched). The postharvest economic losses were less consistently reported and difficult to compare with the global situation due to differences in reporting (monetary amounts or percentages), different sizes of economies and differing product values. For example, postharvest losses were considered large and the order of US$1 to 4 billion and US$4.8 billion per annum for cereals (Egypt and Uganda) and fish (Indonesia) respectively but as low as US$8 to 21 million per annum for tomatoes in Bangladesh. This probably reflects the difficulties in estimating losses as well as valuation. The least known/understood postharvest loss in our analysis was regarding the quality/nutrition losses and was limited to calories in cereals to vitamin A for biofortified cassava. Such information will be critical for countries suffering from nutrition deficiency. Bringing together the estimates for physical, economic and quality/nutrition losses in the OIC Member Countries along with comparisons with the global situation has highlighted a few lessons and gaps. The bulk of the information obtained from the literature review, online survey and case/desk studies concerned the physical losses. This is probably because physical losses are easier to estimate either by direct measurement or by visual inspection. It should be noted however, that all are estimates and few studies are quantitative. Much less was reported concerning the economic losses and the amounts will differ markedly from one value chain for another, even for the same product and commodity. This, therefore, is an area of research that would require more inputs and due to the high cost of undertaking such work, the target value chains would need to be selected according to economic contribution to the OIC Member Country. In all cases the monetary cost of the losses was significant but it was not always known how the costs were estimated. If the monetary losses could be captured, this will lead to benefits for the consumer and actors in the value chain along with potential benefits to national balance of payments. The least known was regarding the quality/nutrition losses but such information may be critical for countries suffering from nutrition deficiency, particularly calories and vitamins. Key findings concerning specific postharvest research issues was sparse and geographically scattered. Some commodities have a greater coverage than others (e.g. artisanal fisheries and maize are far more researched that cattle or bananas). Some OIC Member Countries and regions have seen much more postharvest loss research and practice than others. For example, the Africa Group and low income countries has seen more support, probably from donors, which has been driving postharvest loss research. Commodity specific findings are reported and these relate to the product characteristics, uses and markets they each fall into. For example for the cereals, the challenges were related mainly to drying and storage, especially related to pests in store, whereas for other root crops peeling, storage and marketing were the highest postharvest loss elements reported. For oilseed and pulses, key issues related to storage largely due to the impact of storage pests. For fruit and vegetables, the issue was the high perishability and ease of damage. Meat and meat products issues related to high transport losses for live animals are often a factor of distance to market or slaughter and the absence of infrastructure including adequate cold chains. For milk and dairy products, key issues were related to the need to upgrade the milk and dairy value chains, particularly setting standards, organising farmers and supporting the emergence of cool-chains. Lastly for fish and fish products, the key issues related to postharvest losses in aquaculture. Investments in cold chains and improved postharvest handling could substantially reduce postharvest losses and food safety concerns. A range of common challenges were identified. These include the underestimation of the impact of rodents on losses, the importance of the impact of actions taken on farm that can affect postharvest losses, the impact of toxins such as aflatoxin, the benefit from development of cold-chain infrastructure and the existence of policies supporting strategic crops has, in some cases, led to a history of under-investment in postharvest management by the private sector. The impact of gender also appears to have under investigated or reported. A range of common solutions were identified on the farm, in the postharvest value chain and ones that were systemic such as rules and standards, capacity and training etc. For example breeding to improve the storability of fruit and vegetables and root and tuber crops would reduce losses, early quality differentiation to improve marketability etc. A number of examples of best practice were given related to ownership, the value of ICT technology, investment for stored fruit and vegetables and sharing information via mobile phones, strategic investment such as cold chain infrastructure, the emergence of new industries from waste, multi-actor collaboration and the importance of national loss-reporting systems (for example APHLIS and Indonesian Fisheries Sector). A number of policy recommendations were suggested to advise OIC Member Countries locate and quantify postharvest losses. These focused on the need for establishing national postharvest loss reduction coordination approaches, establishing consistent methods, sharing best practice and promoting system wide efforts, promoting capacity building and sharing among OIC Member Countries, facilitating local, national and, potentially, regional multi-stakeholder commodity platforms etc. Lastly, to overcome the challenge that postharvest losses is generally more complex than pre-harvest losses due to the greater diversity of products and end uses and markets that the products are directed at a strategy for prioritise which commodity groups and value chains are most important at the national level was suggested

Smallholder grain postharvest management in a variable climate: Practices and perceptions of smallholder farmers and their service-providers in semi-arid areas

Field data on current crop postharvest management practices and perceptions from smallholder farming communities in an increasingly variable climate are scarce. Our study used a multi-dimensional approach to explore the practices and perceptions of these communities and their service-providers regarding grain postharvest management in semi-arid Mbire and Hwedza districts in Zimbabwe. A total of 601 individual household interviews, six focus group discussions with women and men, and interviews with 40 district stakeholders and 53 community key informants were conducted. Farmers and service-providers explained how climate change was threatening food security; causing reduced and more variable maize and sorghum yields of below 0.5 t/ha, alongside higher grain storage insect pest pressure. Increased food insecurity and concerns regarding grain theft have driven a shift from bulk storage in traditional outdoor free-standing granaries to polypropylene bags stacked inside the living quarters. Poor and improper use of grain protectants in these circumstances exacerbate the health-related risks. Agricultural extension officers were the most common source of agronomic and postharvest information followed by farmer-to-farmer information exchange. Targeted postharvest training; participatory field trials involving agricultural extension staff, farmers and other service-providers; and policy dialogue around grain postharvest management and food security are proposed to help in strengthening the capacity to reduce grain postharvest losses under increasingly unpredictable conditions

Counting losses to cut losses: quantifying legume postharvest losses to help achieve food and nutrition security

Projections suggest that by 2050 global food production will need to have increased by 70% to meet food demands associated with the world’s population growth. Such forecasts, alongside growing awareness of the socio-ecological costs of food loss, and political ramifications of food crises have seen postharvest loss (PHL) reduction reappearing as a development priority. Particularly so in sub-Saharan Africa, a region deemed highly vulnerable to the impacts of climate change, where 307 million people are already affected by severe food insecurity, and the population is projected to double by 2050. Targets for reduced PHL are emphasised in the African Union’s Malabo Declaration and Sustainable Development Goal 12.3. However, crop postharvest systems are complex and losses occur in various ways at different activity stages and due to a host of diverse reasons. To better target and prioritise loss reduction investments and policies we need to understand how much food is being lost postharvest, where, and why. The African Postharvest Losses Information Systems (APHLIS), brought a rigorous knowledge management approach to cereal PHLs. We are now expanding this to include key legume and other crops and estimates of the nutritional and financial values of these losses. The scientific literature was screened to build profiles of the PHLs occurring along the value chains, and combined with contextual information, to provide science-based estimates of PHLs where direct measurements are not available. We discuss these legume PHL profiles and the related opportunities and knowledge gaps