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Articles 241 - 270 of 443

Full-Text Articles in Agricultural Science

Genetic Structure And Diversity Of Western Flower Thrips, Frankliniella Occidentalis In A French Bean Agroecosystem Of Kenya, P. Hondelmann, J. O. Nyasani, S. Subramanian, R. Meyhöfer Jun 2017

Genetic Structure And Diversity Of Western Flower Thrips, Frankliniella Occidentalis In A French Bean Agroecosystem Of Kenya, P. Hondelmann, J. O. Nyasani, S. Subramanian, R. Meyhöfer

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Western flower thrips (WFT) (Frankliniella occidentalis) is an introduced pest that harms French bean production in Kenya and other countries. Since new WFT management approaches are being developed, a closer look at the genetic makeup of WFT populations can give new insights into source habitats, crop colonization patterns or host plant preferences, which are prerequisites for integrated pest management (IPM) strategies. For this purpose, we used six microsatellite loci to analyse the genetic structure, diversity and gene flow of WFT sampled on French beans, intercrops and weeds in Kenyan French bean production areas. The results of this preliminary study indicate …

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Evaluation Of Onion (Allium Cepa) Germplasm Entries For Resistance To Onion Thrips, Thrips Tabaci (Lindeman) In Tanzania, Gabriel Michael Njau, Agnes M.S. Nyomora, Fekadu Fufa Dinssa, Jian Cheng Chang, P. Malini, S. Subramanian, R. Srinivasan Jun 2017

Evaluation Of Onion (Allium Cepa) Germplasm Entries For Resistance To Onion Thrips, Thrips Tabaci (Lindeman) In Tanzania, Gabriel Michael Njau, Agnes M.S. Nyomora, Fekadu Fufa Dinssa, Jian Cheng Chang, P. Malini, S. Subramanian, R. Srinivasan

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Onion thrips, Thrips tabaci (Lindeman), is a prominent species infesting onion and tomato in the northern highlands of Tanzania. It causes considerable leaf damage by direct feeding and also transmits the Iris yellow spot virus (IYSV). Hence, one of the objectives of this study was to identify the most resistant onion entries against T. tabaci. One highly resistant (VI038552) and two resistant onion entries (VI038512 and AVON 1067) were identified against T. tabaci. Besides thrips resistance, the bulb size of VI038512 was also equivalent to one of the commercial varieties, Texas. The highly resistant VI038552 recorded the highest yield, followed …

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Returns To Research And Outreach For Integrated Pest Management Of Western Flower Thrips Infesting French Bean And Tomato In Kenya, E. A. Mujuka, H. Affognon, B. W. Muriithi, S. Subramanian, P. Irungu, J. Mburu Jun 2017

Returns To Research And Outreach For Integrated Pest Management Of Western Flower Thrips Infesting French Bean And Tomato In Kenya, E. A. Mujuka, H. Affognon, B. W. Muriithi, S. Subramanian, P. Irungu, J. Mburu

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Thrips, Frankliniella occidentalis (Pergande), is a major invasive pest that causes extensive yield losses in French bean and tomato in Kenya. Thrips management is based on the application of pesticides. In addition to increased environmental risks associated with pesticides, frequent use of these chemicals increases production costs and pesticide resistance. Furthermore, exports are restricted due to non-compliance to maximum residue levels in important consumer export markets, especially the European Union (EU). This study was conducted to estimate the potential benefits of the effectiveness of the icipe-developed strategy for control of western flower thrips before dissemination of the technology in Kenya, …

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Effect Of Organic And Conventional Farming Systems On Nitrogen Use Efficiency Of Potato, Maize And Vegetables In The Central Highlands Of Kenya, Martha W. Musyoka, Noah Adamtey, Anne W. Muriuki, Georg Cadisch May 2017

Effect Of Organic And Conventional Farming Systems On Nitrogen Use Efficiency Of Potato, Maize And Vegetables In The Central Highlands Of Kenya, Martha W. Musyoka, Noah Adamtey, Anne W. Muriuki, Georg Cadisch

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Increased per capita food production in the tropics is closely tied to soil organic matter and water management, timely nitrogen (N) supply and crop N use efficiency (NUE) which are influenced by farming systems. However, there is lack of data on the effect of organic farming systems on NUE and how this compares to conventional farming systems under tropical conditions. Therefore, the objectives of this study were to determine the effect of conventional and organic farming systems at low and high management intensities on N uptake and N use efficiency of potato (Solanum tuberosum L.), maize (Zea mays L.), cabbage …

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Deinbollia Mosaic Virus: A Novel Begomovirus Infecting The Sapindaceous Weed Deinbollia Borbonica In Kenya And Tanzania, Martina Kyallo, Peter Sseruwagi, Robert A. Skilton, Mildred Ochwo-Ssemakula, Peter Wasswa, Joseph Ndunguru May 2017

Deinbollia Mosaic Virus: A Novel Begomovirus Infecting The Sapindaceous Weed Deinbollia Borbonica In Kenya And Tanzania, Martina Kyallo, Peter Sseruwagi, Robert A. Skilton, Mildred Ochwo-Ssemakula, Peter Wasswa, Joseph Ndunguru

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Four isolates of a bipartite begomovirus from naturally infected Deinbollia borbonica plants exhibiting yellow mosaic symptoms in Kenya and Tanzania were molecularly characterised. The DNA-A was most closely related to that of tomato leaf curl Mayotte virus (AM701764; 82%), while the DNA-B shared the highest nucleotide sequence identity with that of East African cassava mosaic virus (AJ704953) at 65%. Based on the current ICTV species demarcation criterion for the genus Begomovirus (≥91% sequence identity for the complete DNA-A), we report the full-length genome sequence of this novel bipartite begomovirus. The results reveal additional diversity and reservoir hosts of begomoviruses in …

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Predicting Stem Borer Density In Maize Using Rapideye Data And Generalized Linear Models, Elfatih M. Abdel-Rahman, Tobias Landmann, Richard Kyalo, George Ong'amo, Sizah Mwalusepo, Saad Sulieman, Bruno Le Ru May 2017

Predicting Stem Borer Density In Maize Using Rapideye Data And Generalized Linear Models, Elfatih M. Abdel-Rahman, Tobias Landmann, Richard Kyalo, George Ong'amo, Sizah Mwalusepo, Saad Sulieman, Bruno Le Ru

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Average maize yield in eastern Africa is 2.03 t ha−1 as compared to global average of 6.06 t ha−1 due to biotic and abiotic constraints. Amongst the biotic production constraints in Africa, stem borers are the most injurious. In eastern Africa, maize yield losses due to stem borers are currently estimated between 12% and 21% of the total production. The objective of the present study was to explore the possibility of RapidEye spectral data to assess stem borer larva densities in maize fields in two study sites in Kenya. RapidEye images were acquired for the Bomet (western Kenya) test site …

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A Survey Of Root Knot Nematodes And Resistance To Meloidogyne Incognita In Sweet Potato Varieties From Kenyan Fields, Hannah W. Karuri, Daniel Olago, Roy Neilson, Enock Mararo, Jandouwe Villinger Feb 2017

A Survey Of Root Knot Nematodes And Resistance To Meloidogyne Incognita In Sweet Potato Varieties From Kenyan Fields, Hannah W. Karuri, Daniel Olago, Roy Neilson, Enock Mararo, Jandouwe Villinger

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The root knot nematode, Meloidogyne is one of the most economically damaging plant parasitic nematode groups, and are widely distributed in Kenyan agro-ecosystems. The aim of this study was to determine the diversity of Meloidogyne species in Kenyan sweet potato fields and identify sweet potato varieties that exhibit resistance to M. incognita. Meloidogyne species were collected from Nyanza, Western, Eastern and Central Provinces of Kenya. Mitochondrial DNA was used to differentiate Meloidogyne species. The most common species in all sampled regions was M. incognita. Meloidogyne hapla was recorded for the first time in Kenyan sweet potato growing areas (Mosocho, Matayos, …

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Diversity Of Lepidopteran Stemborers And Their Parasitoids On Maize And Wild Host Plants In The Rain Forest Of Kisangani, Dr Congo, Onésime Mubenga Kankonda, Benjamin Dudu Akaibe, George Otieno Ong’Amo, Bruno Pierre Le Ru Feb 2017

Diversity Of Lepidopteran Stemborers And Their Parasitoids On Maize And Wild Host Plants In The Rain Forest Of Kisangani, Dr Congo, Onésime Mubenga Kankonda, Benjamin Dudu Akaibe, George Otieno Ong’Amo, Bruno Pierre Le Ru

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Lepidopteran stemborers are considered as the most important insect pests of cereal crops in Sub-Saharan Africa. However, limited information exists on stemborers and their parasitoids in the rain forest of the DR Congo. In order to enhance the understanding of the pest ecology, sampling in both cultivated and wild habitats has been recommended as a bottom line to any action aiming at the design of pest management measures. Following this recommendation, a survey was carried out in the rain forest of the DR Congo on maize and wild host plants. We collected eighteen stemborer and one earborer species belonging to …

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Farm Production, Market Access And Dietary Diversity In Malawi, Stefan Koppmair, Menale Kassie, Matin Qaim Feb 2017

Farm Production, Market Access And Dietary Diversity In Malawi, Stefan Koppmair, Menale Kassie, Matin Qaim

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Objective The association between farm production diversity and dietary diversity in rural smallholder households was recently analysed. Most existing studies build on household-level dietary diversity indicators calculated from 7d food consumption recalls. Herein, this association is revisited with individual-level 24 h recall data. The robustness of the results is tested by comparing household- and individual-level estimates. The role of other factors that may influence dietary diversity, such as market access and agricultural technology, is also analysed. Design A survey of smallholder farm households was carried out in Malawi in 2014. Dietary diversity scores are calculated from 24 h recall data. …

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Impact Of Push-Pull Technology On The Nutritional Status Of Farmers' Children In Western Kenya, Nicholas O. Ogot, J. O. Pittchar, C. A.O. Midega, Z. R. Khan Jan 2017

Impact Of Push-Pull Technology On The Nutritional Status Of Farmers' Children In Western Kenya, Nicholas O. Ogot, J. O. Pittchar, C. A.O. Midega, Z. R. Khan

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This study examined the impact of push-pull technology (PPT) on the nutritional status of children aged 1-12 years. Non-push-pull (NPPT) farmers were used as a control group to establish a comparative model for this study. It determined household production, consumption, and surpluses, comparing the PPT adopters to the nonadopters; found out the incomes and food expenditures from farm products; found out the household dietary diversity scores; and finally found the nutritional status of the two household groups. A six faceted household-level metrics was employed. A sample of 216 households that registered 326 children was derived. This study was conducted in …

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Determinants Of Integrated Soil Fertility Management Technologies Adoption By Smallholder Farmers In The Chinyanja Triangle Of Southern Africa, Powell Mponela, Lulseged Tamene, Gift Ndengu, Ruth Magreta, Job Kihara, Nelson Mango Dec 2016

Determinants Of Integrated Soil Fertility Management Technologies Adoption By Smallholder Farmers In The Chinyanja Triangle Of Southern Africa, Powell Mponela, Lulseged Tamene, Gift Ndengu, Ruth Magreta, Job Kihara, Nelson Mango

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Integrated Soil Fertility Management (ISFM) technologies have proven to be viable options for improving land productivity and increasing yield. However, adoption of the set of complementary technologies that are required in ISFM is quite variable and studies tend to focus on single technologies. In this study we used cluster analysis to group technologies and ordered probit to determine the probability of multiple technology adoption. The result show that usage of ISFM in the Chinyanja Triangle (Southern Africa) is grouped into 3 technological sets based on complementarities. The set of nutrient dense technologies of inorganic fertiliser, compost and animal manure (ISFMset3) …

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Managing Storage Pests Of Maize: Farmers' Knowledge, Perceptions And Practices In Western Kenya, Charles A.O. Midega, Alice W. Murage, Jimmy O. Pittchar, Zeyaur R. Khan Dec 2016

Managing Storage Pests Of Maize: Farmers' Knowledge, Perceptions And Practices In Western Kenya, Charles A.O. Midega, Alice W. Murage, Jimmy O. Pittchar, Zeyaur R. Khan

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Insect pests are a key constraint to effective utilization of cereal crops in sub-Saharan Africa (SSA), with damage caused by these pests in the stores of particular concern. Although a number of approaches have been advanced for control of storage pests of maize, uptake remains a challenge, with effectiveness of some approaches being questionable. We conducted a survey in western Kenya among 330 respondents using face to face interviews and focus group discussions to evaluate farmers' practices, knowledge and perceptions of storage pests of maize, and their current practices in managing such pests as a basis for development of efficient …

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Exploring Factors That Shape Small-Scale Farmers’ Opinions On The Adoption Of Eco-Friendly Nets For Vegetable Production, F. Vidogbéna, A. Adégbidi, R. Tossou, F. Assogba-Komlan, T. Martin, M. Ngouajio, S. Simon, L. Parrot, S. T. Garnett, K. K. Zander Dec 2016

Exploring Factors That Shape Small-Scale Farmers’ Opinions On The Adoption Of Eco-Friendly Nets For Vegetable Production, F. Vidogbéna, A. Adégbidi, R. Tossou, F. Assogba-Komlan, T. Martin, M. Ngouajio, S. Simon, L. Parrot, S. T. Garnett, K. K. Zander

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If agro-ecological systems are to realize their potential as sustainable alternatives to conventional agricultural systems, innovation diffusion needs to be enhanced. We conducted surveys among 214 small-scale vegetable farmers in Benin, a food-deficit country in West Africa, on how they perceived the different attributes of eco-friendly nets (EFNs). The nets act as physical barriers against insects in vegetable production and so reduce pesticide use. Understanding farmer perceptions about new technologies helps reveal farmers’ propensity to adopt them. Intensity of attitude was measured on a Likert scale, and an ordered probit model was used to determine which characteristics of nets were …

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On-Farm Maize Storage Systems And Rodent Postharvest Losses In Six Maize Growing Agro-Ecological Zones Of Kenya, Kukom Edoh Ognakossan, Hippolyte D. Affognon, Christopher M. Mutungi, Daniel N. Sila, Soul Kifouly G. Midingoyi, Willis O. Owino Dec 2016

On-Farm Maize Storage Systems And Rodent Postharvest Losses In Six Maize Growing Agro-Ecological Zones Of Kenya, Kukom Edoh Ognakossan, Hippolyte D. Affognon, Christopher M. Mutungi, Daniel N. Sila, Soul Kifouly G. Midingoyi, Willis O. Owino

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Rodents are one of the major postharvest pests that affect food security by impacting on both food availability and safety. However, knowledge of the impact of rodents in on-farm maize storage systems in Kenya is limited. A survey was conducted in 2014 to assess magnitudes of postharvest losses in on-farm maize storage systems in Kenya, and the contribution of rodents to the losses. A total of 630 farmers spread across six maize growing agro-ecological zones (AEZs) were interviewed. Insects, rodents and moulds were the main storage problems reported by farmers. Storage losses were highest in the moist transitional and moist …

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Spatial And Temporal Spread Of Maize Stem Borer Busseola Fusca (Fuller) (Lepidoptera: Noctuidae) Damage In Smallholder Farms, Frank T. Ndjomatchoua, Henri E.Z. Tonnang, Christophe Plantamp, Pascal Campagne, Clément Tchawoua, Bruno P. Le Ru Nov 2016

Spatial And Temporal Spread Of Maize Stem Borer Busseola Fusca (Fuller) (Lepidoptera: Noctuidae) Damage In Smallholder Farms, Frank T. Ndjomatchoua, Henri E.Z. Tonnang, Christophe Plantamp, Pascal Campagne, Clément Tchawoua, Bruno P. Le Ru

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The main purpose of this study was to understand the spatio-temporal spread of the maize stem borer Busseola fusca (Fuller) (Lepidoptera: Noctuidae) in smallholder maize farms. The analysis carried out allowed the establishment of complementary sampling scheme and analysis that can be applied to investigate the propagation of stem borer damages and extended to other insect pests. This approach requires consideration of all plants point locations, the knowledge on the level of damage and its characterization. Results showed that there was a two-week interval between occurrence of the peaks of leaf damage and male adult moth abundance. The prior role …

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Productivity, Profitability And Partial Nutrient Balance In Maize-Based Conventional And Organic Farming Systems In Kenya, Noah Adamtey, Martha W. Musyoka, Christine Zundel, Juan Guillermo Cobo, Edward Karanja, Komi K.M. Fiaboe, Anne Muriuki, Monicah Mucheru-Muna, Bernard Vanlauwe, Estelle Berset, Monika M. Messmer, Andreas Gattinger, Gurbir S. Bhullar, Georg Cadisch, Andreas Fliessbach, Paul Mäder, Urs Niggli, Dionys Foster Nov 2016

Productivity, Profitability And Partial Nutrient Balance In Maize-Based Conventional And Organic Farming Systems In Kenya, Noah Adamtey, Martha W. Musyoka, Christine Zundel, Juan Guillermo Cobo, Edward Karanja, Komi K.M. Fiaboe, Anne Muriuki, Monicah Mucheru-Muna, Bernard Vanlauwe, Estelle Berset, Monika M. Messmer, Andreas Gattinger, Gurbir S. Bhullar, Georg Cadisch, Andreas Fliessbach, Paul Mäder, Urs Niggli, Dionys Foster

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In 2007 two long-term trials were established in Kenya to contribute research-based evidence to the global debate on the productivity, economic viability and sustainability of different agricultural production systems. These trials compare conventional (Conv) and organic (Org) farming systems at high and low input levels at two locations, i.e. Chuka, with Humic Nitisols, high inherent soil fertility and rainfall, and Thika, with Rhodic Nitisols with low soil fertility and rainfall. The high input systems (High) represent commercial-scale, export-oriented production that uses the recommended amounts of fertilisers, pesticides and irrigation water to generate high yields, whilst the low input systems (Low) …

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Frequency And Time Pattern Differences In Acoustic Signals Produced By Prostephanus Truncatus (Horn) (Coleoptera: Bostrichidae) And Sitophilus Zeamais (Motschulsky) (Coleoptera: Curculionidae) In Stored Maize, A. W. Njoroge, H. Affognon, C. Mutungi, B. Rohde, U. Richter, O. Hensel, R. W. Mankin Oct 2016

Frequency And Time Pattern Differences In Acoustic Signals Produced By Prostephanus Truncatus (Horn) (Coleoptera: Bostrichidae) And Sitophilus Zeamais (Motschulsky) (Coleoptera: Curculionidae) In Stored Maize, A. W. Njoroge, H. Affognon, C. Mutungi, B. Rohde, U. Richter, O. Hensel, R. W. Mankin

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Frequency spectra and timing patterns of brief, 1-10 ms broadband sound impulses produced by movement and feeding activities of Prostephanus truncatus and Sitophilus zeamais last instars and adults in maize were investigated to find spectral and temporal pattern information useful for distinguishing among these species and stages. The impulse spectra were categorized into five different types of frequency patterns (profiles), designated Broadband, HighF, MidF1, MidF2 and LowF to indicate differences in their peak energies and broadness of frequency range. Groups (trains) of three or more closely spaced impulses, termed bursts, were observed to occur frequently in all recordings, as has …

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Effect Of Triple-Layer Hermetic Bagging On Mould Infection And Aflatoxin Contamination Of Maize During Multi-Month On-Farm Storage In Kenya, J. Ng'ang'a, C. Mutungi, S. Imathiu, H. Affognon Oct 2016

Effect Of Triple-Layer Hermetic Bagging On Mould Infection And Aflatoxin Contamination Of Maize During Multi-Month On-Farm Storage In Kenya, J. Ng'ang'a, C. Mutungi, S. Imathiu, H. Affognon

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Field trials were conducted in small-scale farmers' grain stores in an aflatoxin endemic region to assess the effect of storing maize in triple layer hermetic (PICS™) bags on aflatoxin contamination. Shelled maize grain was purchased from farmers, and filled into PICS bags, woven polypropylene (PP) and jute bags and kept in the farmers' own stores for 35 weeks. Grain moisture content, total mould count and mould incidence levels were examined at onset and after every 7 weeks during the 35 weeks of storage. Aflatoxin contamination was examined at onset, and after 14, 28 and 35 weeks. Ambient temperature and r.h. …

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Survey Of Nematodes Associated With Terrestrial Slugs In Norway, J. L. Ross, E. S. Ivanova, B. A. Hatteland, M. B. Brurberg, S. Haukeland Sep 2016

Survey Of Nematodes Associated With Terrestrial Slugs In Norway, J. L. Ross, E. S. Ivanova, B. A. Hatteland, M. B. Brurberg, S. Haukeland

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A survey of nematodes associated with terrestrial slugs was conducted for the first time in Norway. A total of 611 terrestrial slugs were collected from 32 sample sites. Slugs were identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. Twelve slug species were identified, representing four different slug families. Internal nematodes were identiï¬'d by means of morphological analysis and the sequencing of the 18S rRNA gene. Of the sample sites studied, 62.5% were found to be positive for nematode parasites, with 18.7% of all slugs discovered being infected. Five nematode species were identified in …

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Farmers' Knowledge And Perception Of Grain Legume Pests And Their Management In The Eastern Province Of Kenya, Andnet Abtew, Saliou Niassy, Hippolyte Affognon, Sevgan Subramanian, Serge Kreiter, Giovanna Tropea Garzia, Thibaud Martin Sep 2016

Farmers' Knowledge And Perception Of Grain Legume Pests And Their Management In The Eastern Province Of Kenya, Andnet Abtew, Saliou Niassy, Hippolyte Affognon, Sevgan Subramanian, Serge Kreiter, Giovanna Tropea Garzia, Thibaud Martin

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Grain legumes play an important role in community livelihood and in the national economy in Kenya. Unfortunately, in many African countries, production doesn't satisfy the demand in grains due to various constrains. Understanding farmers practices and behavior in the management of grain legume pests is a crucial step in the development of sustainable management strategies. A total of 216 farmers were surveyed in eight districts of eastern Kenya to evaluate farmers' knowledge and perceptions of grain legume pests; to examine current pest management practices, and to identify other production constraints. Grain legumes are grown by a wide age-group of farmers, …

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Application Of Superabsorbent Polymers (Sap) As Desiccants To Dry Maize And Reduce Aflatoxin Contamination, Duncan O. Mbuge, Renata Negrini, Livine O. Nyakundi, Serge P. Kuate, Ranajit Bandyopadhyay, William M. Muiru, Baldwyn Torto, Raffaele Mezzenga Aug 2016

Application Of Superabsorbent Polymers (Sap) As Desiccants To Dry Maize And Reduce Aflatoxin Contamination, Duncan O. Mbuge, Renata Negrini, Livine O. Nyakundi, Serge P. Kuate, Ranajit Bandyopadhyay, William M. Muiru, Baldwyn Torto, Raffaele Mezzenga

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The ability of superabsorbent polymers (SAP) in drying maize and controlling aflatoxin contamination was studied under different temperatures, drying times and SAP-to-maize ratios. Temperature and drying time showed significant influence on the aflatoxin formation. SAP-to-maize ratios between 1:1 and 1:5 showed little or no aflatoxin contamination after drying to the optimal moisture content (MC) of 13 %, while for ratios 1:10 and 1:20, aflatoxin contamination was not well controlled due to the overall higher MC and drying time, which made these ratios unsuitable for the drying process. Results clearly show that temperature, frequency of SAP change, drying time and SAP-to-maize …

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Opposing Roles Of Foliar And Glandular Trichome Volatile Components In Cultivated Nightshade Interaction With A Specialist Herbivore, Lucy Kananu Murungi, Hillary Kirwa, Daisy Salifu, Baldwyn Torto Aug 2016

Opposing Roles Of Foliar And Glandular Trichome Volatile Components In Cultivated Nightshade Interaction With A Specialist Herbivore, Lucy Kananu Murungi, Hillary Kirwa, Daisy Salifu, Baldwyn Torto

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Plant chemistry is an important contributor to the interaction with herbivores. Here, we report on a previously unknown role for foliar and glandular trichome volatiles in their interaction with the specialist herbivore of solanaceous plants, the tomato red spider mite Tetranychus evansi.We used various bioassays and chemical analyses including coupled gas chromatography- mass spectrometry (GC/MS) and liquid chromatography coupled to quadrupole time of flight mass spectrometry (LC-QToF-MS) to investigate this interaction between cultivated African nightshades and T. evansi.We show that, whereas morphologically different cultivated African nightshade species released similar foliar volatile organic compounds (VOCs) that attracted T. evansi, VOCs released …

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Understanding Variability In Crop Response To Fertilizer And Amendments In Sub-Saharan Africa, Job Kihara, Generose Nziguheba, Shamie Zingore, Adama Coulibaly, Anthony Esilaba, Vernon Kabambe, Samuel Njoroge, Cheryl Palm, Jeroen Huising Aug 2016

Understanding Variability In Crop Response To Fertilizer And Amendments In Sub-Saharan Africa, Job Kihara, Generose Nziguheba, Shamie Zingore, Adama Coulibaly, Anthony Esilaba, Vernon Kabambe, Samuel Njoroge, Cheryl Palm, Jeroen Huising

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Improved understanding of soil fertility factors limiting crop productivity is important to develop appropriate soil and nutrient management recommendations in sub-Saharan Africa. Diagnostic trials were implemented in Kenya, Malawi, Mali, Nigeria and Tanzania, as part of the African Soils Information Service (AfSIS) project, to identify soil fertility constraints to crop production across various cropping systems and soil fertility conditions. In each country, one to three sites of 10 km × 10 km were included with each site having 12-31 field trials. The treatments tested included a control, an NPK treatment, three treatments in which the N, P and K nutrients …

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Storage Of Pigeonpea Grain (Cajanus Cajan (L.) Millsp.) In Hermetic Triple-Layer Bags Prevents Losses Caused By Callosobruchus Maculatus (F.) (Coleoptera: Bruchidae), H. D. Affognon, A. W. Njoroge, C. M. Mutungi, J. Manono, D. Baributsa, L. L. Murdock Jul 2016

Storage Of Pigeonpea Grain (Cajanus Cajan (L.) Millsp.) In Hermetic Triple-Layer Bags Prevents Losses Caused By Callosobruchus Maculatus (F.) (Coleoptera: Bruchidae), H. D. Affognon, A. W. Njoroge, C. M. Mutungi, J. Manono, D. Baributsa, L. L. Murdock

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Dry pigeonpea grain is susceptible to infestation from the cowpea bruchid during storage. This study investigated the potential of Purdue Improved Cowpea Storage (PICS™) and polypropylene (PP) bags for reducing insect infestation under ambient laboratory conditions for six months. Some of the bags were artificially infested with cowpea bruchid Callosobruchus maculatus (PICS1, PP1) while others were not (PICS0, PP0). In an additional trial, PP bags containing pigeonpeas were treated with Actellic Super® dust before being artificially infested (PP1Ac). Moisture content, number of live C. maculatus adults, grain damage, and weight loss were determined at monthly intervals. Temperature and relative humidity …

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Maize Response To Macronutrients And Potential For Profitability In Sub-Saharan Africa, J. Kihara, J. Huising, G. Nziguheba, B. S. Waswa, S. Njoroge, V. Kabambe, E. Iwuafor, C. Kibunja, A. O. Esilaba, A. Coulibaly Jul 2016

Maize Response To Macronutrients And Potential For Profitability In Sub-Saharan Africa, J. Kihara, J. Huising, G. Nziguheba, B. S. Waswa, S. Njoroge, V. Kabambe, E. Iwuafor, C. Kibunja, A. O. Esilaba, A. Coulibaly

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Sub-Saharan Africa (SSA) is plagued by low productivity and little research is available on the attainable responses and profitability to applied nutrients under variable environments. The objective of this study was to determine the attainable maize grain response to and potential of profitability of N, P and K application in SSA using boundary line approaches. Data from experiments conducted in SSA under AfSIS project (2009–2012) and from FAO trials database (1969–1996) in 15 countries and constituting over 375 different experimental locations and 6600 data points are used. Both response to fertilizer and value cost ratio (VCR) are highly variable and …

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An Indirect Defence Trait Mediated Through Egg-Induced Maize Volatiles From Neighbouring Plants, Daniel M. Mutyambai, Toby J.A. Bruce, Johnnie Van Den Berg, Charles A.O. Midega, John A. Pickett, Zeyaur R. Khan Jul 2016

An Indirect Defence Trait Mediated Through Egg-Induced Maize Volatiles From Neighbouring Plants, Daniel M. Mutyambai, Toby J.A. Bruce, Johnnie Van Den Berg, Charles A.O. Midega, John A. Pickett, Zeyaur R. Khan

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Attack of plants by herbivorous arthropods may result in considerable changes to the plant's chemical phenotype with respect to emission of herbivore-induced plant volatiles (HIPVs). These HIPVs have been shown to act as repellents to the attacking insects as well as attractants for the insects antagonistic to these herbivores. Plants can also respond to HIPV signals from other plants that warn them of impending attack. Recent investigations have shown that certain maize varieties are able to emit volatiles following stemborer egg deposition. These volatiles attract the herbivore's parasitoids and directly deter further oviposition. However, it was not known whether these …

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Sustainable Intensification Of Agricultural Systems In The Central African Highlands: The Need For Institutional Innovation, Marc Schut, Piet Van Asten, Chris Okafor, Cyrille Hicintuka, Sylvain Mapatano, Nsharwasi Léon Nabahungu, Desire Kagabo, Perez Muchunguzi, Emmanuel Njukwe, Paul M. Dontsop-Nguezet, Murat Sartas, Bernard Vanlauwe Jun 2016

Sustainable Intensification Of Agricultural Systems In The Central African Highlands: The Need For Institutional Innovation, Marc Schut, Piet Van Asten, Chris Okafor, Cyrille Hicintuka, Sylvain Mapatano, Nsharwasi Léon Nabahungu, Desire Kagabo, Perez Muchunguzi, Emmanuel Njukwe, Paul M. Dontsop-Nguezet, Murat Sartas, Bernard Vanlauwe

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This study identifies entry points for innovation for sustainable intensification of agricultural systems. An agricultural innovation systems approach is used to provide a holistic image of (relations between) constraints faced by different stakeholder groups, the dimensions and causes of these constraints, and intervention levels, timeframes and types of innovations needed. Our data shows that constraints for sustainable intensification of agricultural systems are mainly of economic and institutional nature. Constraints are caused by the absence, or poor functioning of institutions such as policies and markets, limited capabilities and financial resources, and ineffective interaction and collaboration between stakeholders. Addressing these constraints would …

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Low Permeability Triple-Layer Plastic Bags Prevent Losses Of Maize Caused By Insects In Rural On-Farm Stores, Jeremiah Ng’Ang’A, Christopher Mutungi, Samuel M. Imathiu, Hippolyte Affognon Jun 2016

Low Permeability Triple-Layer Plastic Bags Prevent Losses Of Maize Caused By Insects In Rural On-Farm Stores, Jeremiah Ng’Ang’A, Christopher Mutungi, Samuel M. Imathiu, Hippolyte Affognon

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Participatory on-farm trials were conducted to assess effectiveness of Purdue Improved Crop Storage (PICS™) bags for storage of maize in small-scale farmers’ stores in rural villages in eastern Kenya. A PICS bag is a three-layered hermetic bag-system that forms a barrier against the influx of oxygen and the escape of carbon dioxide. Jute, woven polypropylene or PICS bags were filled with shelled maize grain, purchased from the participating farmers, and the three sets of bags kept in the farmers’ own stores for 35 weeks. Oxygen and carbon dioxide levels in the PICS bags were monitored, as well as the temperature …

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Can Climate-Driven Change Influence Silicon Assimilation By Cereals And Hence The Distribution Of Lepidopteran Stem Borers In East Africa?, P. A. Calatayud, E. Njuguna, S. Mwalusepo, M. Gathara, G. Okuku, A. Kibe, B. Musyoka, D. Williamson, G. Ong'amo, G. Juma, T. Johansson, S. Subramanian, E. Gatebe, B. Le Ru May 2016

Can Climate-Driven Change Influence Silicon Assimilation By Cereals And Hence The Distribution Of Lepidopteran Stem Borers In East Africa?, P. A. Calatayud, E. Njuguna, S. Mwalusepo, M. Gathara, G. Okuku, A. Kibe, B. Musyoka, D. Williamson, G. Ong'amo, G. Juma, T. Johansson, S. Subramanian, E. Gatebe, B. Le Ru

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In East Africa, lepidopteran stemborers such as Chilo partellus and Busseola fusca are major constraints to production of maize, which is the main staple food crop in the region. Cereals depend on silicon (Si)-based defences to fight off herbivores. Using altitudinal ranges in the East African highlands as ecological surrogates for inferring climate change, it was shown that Si concentrations in soil and maize decreased with altitude. This was attributed, in part, to low temperatures at high altitudes, which negatively affected Si assimilation by maize. Experiments showed that B. fusca was more susceptible to Si than C. partellus. Hence the …

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Influence Of Host-Plant Surface Chemicals On The Oviposition Of The Cereal Stemborer Busseola Fusca, Gerald Juma, Gilles Clément, Peter Ahuya, Ahmed Hassanali, Sylvie Derridj, Cyrile Gaertner, Romain Linard, Bruno Le Ru, Brigitte Frérot, Paul André Calatayud May 2016

Influence Of Host-Plant Surface Chemicals On The Oviposition Of The Cereal Stemborer Busseola Fusca, Gerald Juma, Gilles Clément, Peter Ahuya, Ahmed Hassanali, Sylvie Derridj, Cyrile Gaertner, Romain Linard, Bruno Le Ru, Brigitte Frérot, Paul André Calatayud

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The chemical composition of plant surfaces plays a role in selection of host plants by herbivorous insects. Once the insect reaches the plant, these cues determine host acceptance. Laboratory studies have shown that the stem borer Busseola fusca (Lepidoptera: Noctuidae), an important pest of sorghum and maize in sub-Saharan Africa, is able to differentiate between host and non-host plant species. However, no information is available on the cues used by this insect to seek and accept the host plant. Thus, the role of surface phytochemical stimuli on host selection and oviposition by B. fusca was studied in the laboratory using …

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