Cowpea (Vigna unguiculata L. Walp) grain is an important source of protein for smallholder farmers in developing countries. However, cowpea grains are highly susceptible to bruchid attack, resulting in high quantitative and qualitative postharvest losses (PHLs). We evaluated the performance of five different hermetic bag brands for cowpea grain storage in two contrasting agro-ecological zones of Zimbabwe (Guruve and Mbire districts) for an 8-month storage period during the 2017/18 and 2018/19 storage seasons. The hermetic bag treatments evaluated included: GrainPro Super Grain bags (SGB) IVR™; PICS bags; AgroZ ® Ordinary bags; AgroZ ® Plus bags;ZeroFly ® hermetic bags. These were compared to untreated grain in a polypropylene bag (negative control) and Actellic Gold Dust ® (positive chemical control). All treatments were housed in Authors Accepted Manuscript -06/06/2020 2 farmers' stores and were subjected to natural insect infestation. Hermetic bag treatments were significantly superior (p< 0.001) to non-hermetic storage in limiting grain damage, weight loss and insect population development during storage. However, rodent control is recommended, as rodent attack rendered some hermetic bags less effective. Actellic Gold Dust ® was as effective as the hermetic bags. Callosobruchus rhodesianus (Pic.) populations increased within eight weeks of storage commencement, causing high damage and losses in both quality and quantity, with highest losses recorded in the untreated control. Cowpea grain stored in Mbire district sustained significantly higher insect population and damage than Guruve district which is ascribed to differences in environmental conditions. The parasitic wasp, Dinarmus basalis (Rondani) was suppressed by Actellic Gold Dust ® and all hermetic treatments. All the hermetic bag brands tested are recommended for smallholder farmer use in reducing PHLs while enhancing environmental and worker safety, and food and nutrition security.

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Postharvest losses (PHLs) amplify food insecurity and reduce the amount of nutrients available to vulnerable populations, especially in the world's Low and Middle Income Countries (LMICs). However, little is known about nutrient loss at the various postharvest stages. The objective of our study was to develop a methodology and a tool to estimate nutritional postharvest losses (NPHLs) along food value chains for three distinct food commodities in sub-Saharan Africa. The study used a combination of literature, laboratory and field data to investigate NPHLs caused by both changes in quantity and quality of food material (quantitative and qualitative NPHLs, respectively). The method can be expanded to various other food value chains. A user-friendly predictive tool was developed for case studies involving maize and cowpea in Zimbabwe, and for sweet potato in Uganda. Quantitative and qualitative NPHLs were combined and converted into predicted nutrient loss and nutritional requirement lost due to postharvest losses. The number of people who may not meet their daily nutritional needs, as a result of the food and nutrient losses at country level, was estimated. The estimates consider nutritionally vulnerable groups such as children under five years and pregnant women. The nutrient density of the harvested food material, the level of food production, the postharvest stages along the food value chain, the levels of pest damage along the value chain, and the susceptibility of the nutrients to degradation e.g. during storage, are all important factors that affect NPHLs. Our modelling work suggests that reducing PHLs along food value chains could significantly improve access to nutritious food for populations in LMICs.

Poor storage methods lead to high postharvest losses in maize, an essential staple in sub-Saharan Africa. Smallholder farmers' knowledge and awareness of postharvest nutritional losses (PHNLs), practices regarding maize grain storage, and factors influencing use of improved storage protection practices were investigated in two districts in Zimbabwe through a cross-sectional field survey of 331 households randomly selected from lists of farmers' names kept by local extension staff. A multistage sampling technique was used involving purposively selecting the study districts then randomly selecting the study wards, the villages and the households. Twenty eight key informant were purposively selected being officers and stakeholders working or residing in the two districts and involved in postharvest and nutrition issues. The most commonly used storage practices were the admixture of maize grain with synthetic grain protectant pesticides followed by storage of untreated grain in polypropylene bags. Highly toxic pesticides, such as Cabaryl 85 WP and Acetamiprid 20 SP, which are not registered for stored food grain treatment, were being applied by 14.6% of the farmers to protect their grain from insect attack. We developed a PHNL knowledge index that measured farmers' nutritional knowledge and awareness of PHNL. Level of education and district positively correlated with farmers' PHNL knowledge (p<0.05), whereas the opposite was Authors Accepted Manuscript -Journal: Food Securty 2 found for farmers' age (p<0.05). Multinomial logistic regression analysis showed that use of grain storage protection practices was positively related to farmers' age, total maize grain production, education level and PHNL knowledge (p<0.05). Older farmers were less likely to use non-recommended chemicals to protect their maize grain during storage. Farmers' education level and total maize grain production were positively associated with higher use of synthetic pesticides, while PHNL knowledge was associated with the use of traditional grain protectants (p<0.05). Training on grain storage management, especially safe grain storage protection practices and PHNLs, is essential to contribute towards household food and nutrition security.