Tanya Stathers - Academia.edu (original) (raw)
Papers by Tanya Stathers
Comparative insecticidal efficacy of five raw African diatomaceous earths against three tropical ... more Comparative insecticidal efficacy of five raw African diatomaceous earths against three tropical stored grain Coleopteran pests:
Environmental and safety concerns have created a global drive towards reduction in pesticide use ... more Environmental and safety concerns have created a global drive towards reduction in pesticide use and subsequent withdrawal of some that are considered hazardous, hence increasing the pressure to seek alternatives; and grain protectants have not been spared. Farmers in sub-Saharan Africa (SSA) have repeatedly indicated their concerns about the safety of synthetic insecticides for grain protection. The use of diatomaceous earths (DEs) is one option that has been identified by research as a possible alternative. However, the operationalisation of the DE technology is still constrained by a number of factors including: product availability; product stewardship; applicability on cob maize; high humidity in some parts of SSA which renders the DEs less effective; occurrence of the Larger Grain Borer, Prostephanus truncatus in some countries which requires higher concentrations of DEs for effective control; and grain marketing standards in central storage systems which need to be revised. T...
![Research paper thumbnail of Challenges of grain protection in sub-Saharan Africa: the case of diatomaceous earths - powerpoint presentation, Food Africa International Working Meeting, Palais des Congres, Yaounde, Carmeroon. 5-9 May 2003. [140 participants from 30 countries]](https://attachments.academia-assets.com/77862731/thumbnails/1.jpg)
](Environmental and safety concerns have created a global drive towards reduction in pesticide use ... more Environmental and safety concerns have created a global drive towards reduction in pesticide use and subsequent withdrawal of some that are considered hazardous, hence increasing the pressure to seek alternatives; and grain protectants have not been spared. Farmers in sub-Saharan Africa (SSA) have repeatedly indicated their concerns about the safety of synthetic insecticides for grain protection. The use of diatomaceous earths (DEs) is one option that has been identified by research as a possible alternative. However, the operationalisation of the DE technology is still constrained by a number of factors including: product availability; product stewardship; applicability on cob maize; high humidity in some parts of SSA which renders the DEs less effective; occurrence of the Larger Grain Borer, Prostephanus truncatus in some countries which requires higher concentrations of DEs for effective control; and grain marketing standards in central storage systems which need to be revised. T...
Advances in stored product protection. Proceedings of the 8th International Working Conference on Stored Product Protection, York, UK, 22-26 July 2002
A protocol for the evaluation of the efficacy of diatomaceous earth (DE) as grain protectant was ... more A protocol for the evaluation of the efficacy of diatomaceous earth (DE) as grain protectant was developed. Four DE samples as admixture for wheat were evaluated against laboratory-reared cultures of 7- to 21-day-old unsexed adult Sitophilus oryzae (rice weevil; CSIRO strain 418) and Tribolium castaneum (red flour beetle; CSIRO strain 4). Four different laboratories used this protocol for the evaluation of the DE samples. One laboratory conducted a rapid assessment test that uses physical characteristics to predict insecticidal activity. One laboratory tested the DE samples as surface treatments applied both as a dust and as a slurry. In general, there was good agreement between laboratories, although one laboratory had significantly higher mortality than the other. The possible reasons for this are discussed. The efficacy in the grain bioassay was not correlated with the efficacy in the surface bioassay.
It is universally understood that postharvest losses are high, particularly in less developed eco... more 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 eff...
Treatments & application rates (Aina ya jaribio) Mean % no. of damaged grains (Idadi ya punje zil... more Treatments & application rates (Aina ya jaribio) Mean % no. of damaged grains (Idadi ya punje zilizoharibiwa na .. wadudu kati ya punje 100)
1 Institute of Resource Assessment (IRA), University of Dares Salaam, P. O. Box 35097, Dares sala... more 1 Institute of Resource Assessment (IRA), University of Dares Salaam, P. O. Box 35097, Dares salaam, Tanzania. 2 University of Greenwich, Natural Resources Institute; United Kingdom. 3 University of Malawi, Chancellor College, Department of Geography and Earth Sciences, Box 280, Zomba, Malawi. 4 Hombolo Agriculture Research Institute, Dodoma, Tanzania. 5 Bvumbwe Agriculture Research Station, Bvumbwe, Malawi.
The study explores rural-urban linkages in order to address temporal and spatial dynamics of vuln... more The study explores rural-urban linkages in order to address temporal and spatial dynamics of vulnerability to climate change at the scale of local government, focusing on Blantyre City. The study sought to assess how different groupings of urban consumers access their food and how they are impacted by climate change risks. The study established that food consumed in Blantyre City largely originates from rural areas of Blantyre District (e.g. 80% maize), some districts in the southern region, other parts of Malawi, and other countries. The food is mostly accessed through market purchase and partially own production in surrounding rural areas. The high inter-annual rainfall variations and prolonged dry spells, which pose a major challenge for agricultural production in rural areas, affect food supplies and prices in urban markets. The occurrence impacts different urban groupings in different ways, with the disadvantaged groups being the most vulnerable because of high food costs combi...
This manual is intended to support trainers who are helping Farmer Organisations and their member... more This manual is intended to support trainers who are helping Farmer Organisations and their members in Sub-Saharan Africa to improve the quality of their grain. In so doing, it is expected that the income earning opportunities and the food security of the learners’ households will be increased. Learning how to supply quality grain to the UN World Food Programme and other buyers is a corner stone of the capacity building activities provided by the Purchase for Progress (P4P) initiative. P4P is a partnership of many actors and stakeholders spanning the sectors of smallholder development, market development and food assistance brought together around the WFP food demand platform. By developing the capacity to sell to an institutional buyer such as WFP, smallholder farmers through organizations can acquire the knowledge, skills and confidence needed for engaging with formal markets.
Five raw African diatomaceous earth (DE) samples collected from Tanzania, Zimbabwe, Zambia and So... more Five raw African diatomaceous earth (DE) samples collected from Tanzania, Zimbabwe, Zambia and South Africa were compared in a laboratory bioassay studies at University of Zimbabwe and the Natural Resources Institute, UK, to determine their potential as locally available grain protectants. A commercially available DE sample, Protect-It®, and an untreated control were also included in the study. In UK, each sample was tested at two application rates 2500ppm and 5000ppm whereas in Zimbabwe an additional application rate of 1000ppm was included. These application rates are higher than those at which commercial DEs are commonly used, but much lower than the application rates at which farmers in sub Saharan Africa (SSA) typically admix traditional protectants such as ash and sand with their commodities during storage. The DE samples were admixed with maize or wheat prior to addition of 40-50 14-28 day old Sitophilus zeamais or Tribolium castaneum insects respectively, and adult mortality...
Scientific Reports
Field evaluation of six grain storage technologies under hot and arid conditions (32–42 °C; rainf... more Field evaluation of six grain storage technologies under hot and arid conditions (32–42 °C; rainfall
Researchers decided to explore whether diatomaceous earths (DEs) might meet the grain protection ... more Researchers decided to explore whether diatomaceous earths (DEs) might meet the grain protection demands of rural households. These inert dusts are non-toxic to mammals but deadly to insects absorbing the wax from the insect’s cuticle which leads to water loss and death. Following laboratory studies, promising commercial DEs were trialled collaboratively by researchers and farmers as grain protectants in Zimbabwe. Protect-lt and Dryacide applied at 0.1%w/w were as effective as the synthetic conventional insecticide, Actellic Super dust, in limiting insect damage on stored maize, sorghum and cowpea grains for periods of eight months. However, laboratory studies revealed that the devastating larger grain borer now spread throughout many African countries was more tolerant to DEs than the storage pests found in Zimbabwe. This initiated the testing of DEs in combination with other products. Higher DE application rates of 0.25%w/w, a DE-pyrethroid combination and a local African DE were ...
Comparative insecticidal efficacy of five raw African diatomaceous earths against three tropical ... more Comparative insecticidal efficacy of five raw African diatomaceous earths against three tropical stored grain Coleopteran pests:
Environmental and safety concerns have created a global drive towards reduction in pesticide use ... more Environmental and safety concerns have created a global drive towards reduction in pesticide use and subsequent withdrawal of some that are considered hazardous, hence increasing the pressure to seek alternatives; and grain protectants have not been spared. Farmers in sub-Saharan Africa (SSA) have repeatedly indicated their concerns about the safety of synthetic insecticides for grain protection. The use of diatomaceous earths (DEs) is one option that has been identified by research as a possible alternative. However, the operationalisation of the DE technology is still constrained by a number of factors including: product availability; product stewardship; applicability on cob maize; high humidity in some parts of SSA which renders the DEs less effective; occurrence of the Larger Grain Borer, Prostephanus truncatus in some countries which requires higher concentrations of DEs for effective control; and grain marketing standards in central storage systems which need to be revised. T...
Environmental and safety concerns have created a global drive towards reduction in pesticide use ... more Environmental and safety concerns have created a global drive towards reduction in pesticide use and subsequent withdrawal of some that are considered hazardous, hence increasing the pressure to seek alternatives; and grain protectants have not been spared. Farmers in sub-Saharan Africa (SSA) have repeatedly indicated their concerns about the safety of synthetic insecticides for grain protection. The use of diatomaceous earths (DEs) is one option that has been identified by research as a possible alternative. However, the operationalisation of the DE technology is still constrained by a number of factors including: product availability; product stewardship; applicability on cob maize; high humidity in some parts of SSA which renders the DEs less effective; occurrence of the Larger Grain Borer, Prostephanus truncatus in some countries which requires higher concentrations of DEs for effective control; and grain marketing standards in central storage systems which need to be revised. T...
Advances in stored product protection. Proceedings of the 8th International Working Conference on Stored Product Protection, York, UK, 22-26 July 2002
A protocol for the evaluation of the efficacy of diatomaceous earth (DE) as grain protectant was ... more A protocol for the evaluation of the efficacy of diatomaceous earth (DE) as grain protectant was developed. Four DE samples as admixture for wheat were evaluated against laboratory-reared cultures of 7- to 21-day-old unsexed adult Sitophilus oryzae (rice weevil; CSIRO strain 418) and Tribolium castaneum (red flour beetle; CSIRO strain 4). Four different laboratories used this protocol for the evaluation of the DE samples. One laboratory conducted a rapid assessment test that uses physical characteristics to predict insecticidal activity. One laboratory tested the DE samples as surface treatments applied both as a dust and as a slurry. In general, there was good agreement between laboratories, although one laboratory had significantly higher mortality than the other. The possible reasons for this are discussed. The efficacy in the grain bioassay was not correlated with the efficacy in the surface bioassay.
It is universally understood that postharvest losses are high, particularly in less developed eco... more 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 eff...
Treatments & application rates (Aina ya jaribio) Mean % no. of damaged grains (Idadi ya punje zil... more Treatments & application rates (Aina ya jaribio) Mean % no. of damaged grains (Idadi ya punje zilizoharibiwa na .. wadudu kati ya punje 100)
1 Institute of Resource Assessment (IRA), University of Dares Salaam, P. O. Box 35097, Dares sala... more 1 Institute of Resource Assessment (IRA), University of Dares Salaam, P. O. Box 35097, Dares salaam, Tanzania. 2 University of Greenwich, Natural Resources Institute; United Kingdom. 3 University of Malawi, Chancellor College, Department of Geography and Earth Sciences, Box 280, Zomba, Malawi. 4 Hombolo Agriculture Research Institute, Dodoma, Tanzania. 5 Bvumbwe Agriculture Research Station, Bvumbwe, Malawi.
The study explores rural-urban linkages in order to address temporal and spatial dynamics of vuln... more The study explores rural-urban linkages in order to address temporal and spatial dynamics of vulnerability to climate change at the scale of local government, focusing on Blantyre City. The study sought to assess how different groupings of urban consumers access their food and how they are impacted by climate change risks. The study established that food consumed in Blantyre City largely originates from rural areas of Blantyre District (e.g. 80% maize), some districts in the southern region, other parts of Malawi, and other countries. The food is mostly accessed through market purchase and partially own production in surrounding rural areas. The high inter-annual rainfall variations and prolonged dry spells, which pose a major challenge for agricultural production in rural areas, affect food supplies and prices in urban markets. The occurrence impacts different urban groupings in different ways, with the disadvantaged groups being the most vulnerable because of high food costs combi...
This manual is intended to support trainers who are helping Farmer Organisations and their member... more This manual is intended to support trainers who are helping Farmer Organisations and their members in Sub-Saharan Africa to improve the quality of their grain. In so doing, it is expected that the income earning opportunities and the food security of the learners’ households will be increased. Learning how to supply quality grain to the UN World Food Programme and other buyers is a corner stone of the capacity building activities provided by the Purchase for Progress (P4P) initiative. P4P is a partnership of many actors and stakeholders spanning the sectors of smallholder development, market development and food assistance brought together around the WFP food demand platform. By developing the capacity to sell to an institutional buyer such as WFP, smallholder farmers through organizations can acquire the knowledge, skills and confidence needed for engaging with formal markets.
Five raw African diatomaceous earth (DE) samples collected from Tanzania, Zimbabwe, Zambia and So... more Five raw African diatomaceous earth (DE) samples collected from Tanzania, Zimbabwe, Zambia and South Africa were compared in a laboratory bioassay studies at University of Zimbabwe and the Natural Resources Institute, UK, to determine their potential as locally available grain protectants. A commercially available DE sample, Protect-It®, and an untreated control were also included in the study. In UK, each sample was tested at two application rates 2500ppm and 5000ppm whereas in Zimbabwe an additional application rate of 1000ppm was included. These application rates are higher than those at which commercial DEs are commonly used, but much lower than the application rates at which farmers in sub Saharan Africa (SSA) typically admix traditional protectants such as ash and sand with their commodities during storage. The DE samples were admixed with maize or wheat prior to addition of 40-50 14-28 day old Sitophilus zeamais or Tribolium castaneum insects respectively, and adult mortality...
Scientific Reports
Field evaluation of six grain storage technologies under hot and arid conditions (32–42 °C; rainf... more Field evaluation of six grain storage technologies under hot and arid conditions (32–42 °C; rainfall
Researchers decided to explore whether diatomaceous earths (DEs) might meet the grain protection ... more Researchers decided to explore whether diatomaceous earths (DEs) might meet the grain protection demands of rural households. These inert dusts are non-toxic to mammals but deadly to insects absorbing the wax from the insect’s cuticle which leads to water loss and death. Following laboratory studies, promising commercial DEs were trialled collaboratively by researchers and farmers as grain protectants in Zimbabwe. Protect-lt and Dryacide applied at 0.1%w/w were as effective as the synthetic conventional insecticide, Actellic Super dust, in limiting insect damage on stored maize, sorghum and cowpea grains for periods of eight months. However, laboratory studies revealed that the devastating larger grain borer now spread throughout many African countries was more tolerant to DEs than the storage pests found in Zimbabwe. This initiated the testing of DEs in combination with other products. Higher DE application rates of 0.25%w/w, a DE-pyrethroid combination and a local African DE were ...