42 research outputs found

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

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    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

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

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    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

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    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