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International Centre of Insect Physiology and Ecology

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Articles 241 - 270 of 429

Full-Text Articles in Agricultural Science

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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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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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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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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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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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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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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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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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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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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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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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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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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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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Impact Assessment Of Integrated Pest Management (Ipm) Strategy For Suppression Of Mango-Infesting Fruit Flies In Kenya, Beatrice W. Muriithi, Hippolyte D. Affognon, Gracious M. Diiro, Sarah W. Kingori, Chrysantus M. Tanga, Peterson W. Nderitu, Samira A. Mohamed, Sunday Ekesi Mar 2016

Impact Assessment Of Integrated Pest Management (Ipm) Strategy For Suppression Of Mango-Infesting Fruit Flies In Kenya, Beatrice W. Muriithi, Hippolyte D. Affognon, Gracious M. Diiro, Sarah W. Kingori, Chrysantus M. Tanga, Peterson W. Nderitu, Samira A. Mohamed, Sunday Ekesi

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We utilized two waves of data collected from a sample of mango farmers in Meru County in Kenya to evaluate the impact of Integrated Pest Management (IPM) strategy for controlling fruit flies in mango-production. We specifically explored the effect of five IPM practices including parasitoids (p) and Metarhizium anisopliae-based biopesticides (biop), orchard sanitation (os), spot spray of food bait (fb) and male annihilation technique (mat) on three outcome indicators: farmer pesticide expenditure, farm-level mango fruit yield losses and profit. We fitted difference-in-difference and household fixed effects regression models that account for unobserved heterogeneity across households. Our estimates differentiated the impact …

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Influence Of Temperature On Intra- And Interspecific Resource Utilization Within A Community Of Lepidopteran Maize Stemborers, Eric Siaw Ntiri, Paul Andre Calatayud, Johnnie Van Den Berg, Fritz Schulthess, Bruno Pierre Le Ru Feb 2016

Influence Of Temperature On Intra- And Interspecific Resource Utilization Within A Community Of Lepidopteran Maize Stemborers, Eric Siaw Ntiri, Paul Andre Calatayud, Johnnie Van Den Berg, Fritz Schulthess, Bruno Pierre Le Ru

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Competition or facilitation characterises intra- And interspecific interactions within communities of species that utilize the same resources. Temperature is an important factor influencing those interactions and eventual outcomes. The noctuid stemborers, Busseola fusca and Sesamia calamistis and the crambid Chilo partellus attack maize in sub-Saharan Africa. They often occur as a community of interacting species in the same field and plant at all elevations. The influence of temperature on the intra- And interspecific interactions among larvae of these species, was studied using potted maize plants exposed to varying temperatures in a greenhouse and artificial stems kept at different constant temperatures …

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Developing And Deploying Insect Resistant Maize Varieties To Reduce Pre-And Post-Harvest Food Losses In Africa, Tadele Tefera, Stephen Mugo, Yoseph Beyene Feb 2016

Developing And Deploying Insect Resistant Maize Varieties To Reduce Pre-And Post-Harvest Food Losses In Africa, Tadele Tefera, Stephen Mugo, Yoseph Beyene

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Maize grain yield in Africa is low, 1.5 t ha−1 compared to the global average of 4.9 t ha−1. Maize production in Africa is constrained by various abiotic (drought, soil fertility) and biotic factors (insect pests, weeds and diseases). Stem borers and postharvest insect pests play considerable roles in reducing maize yield through damaging the leaves, stems, ears, and kernels. Stem borers can cause 10–15 % yield losses while the postharvest insect pests, particularly, the larger grain borer and maize weevil, can cause 14–36 % grain losses. The use of chemical insecticides has been recommended; however, in addition to health …

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Active Aggregation Among Sexes In Bean Flower Thrips (Megalurothrips Sjostedti) On Cowpea (Vigna Unguiculata), Saliou Niassy, Sunday Ekesi, Nguya K. Maniania, Benedict Orindi, Gerald B. Moritz, Willem J. De Kogel, Sevgan Subramanian Jan 2016

Active Aggregation Among Sexes In Bean Flower Thrips (Megalurothrips Sjostedti) On Cowpea (Vigna Unguiculata), Saliou Niassy, Sunday Ekesi, Nguya K. Maniania, Benedict Orindi, Gerald B. Moritz, Willem J. De Kogel, Sevgan Subramanian

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Male sexual aggregations are a common territorial, mating-related or resource-based, behaviour observed in diverse organisms, including insects such as thrips. The influence of factors such as plant substrate, time of day, and geographic location on aggregation of thrips is uncertain, therefore we monitored the dispersion of male and female bean flower thrips (BFT), Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), on cowpea, Vigna unguiculata (L.) Walp. (Fabaceae), over three cowpea growth stages and across three cowpea-growing areas of Kenya. Our results indicated that for all the crop growth stages, the density of BFTs varied over the time of day, with higher densities …

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Maize Landraces Are Less Affected By Striga Hermonthica Relative To Hybrids In Western Kenya, Charles A.O. Midega, John Pickett, Antony Hooper, Jimmy Pittchar, Zeyaur R. Khan Jan 2016

Maize Landraces Are Less Affected By Striga Hermonthica Relative To Hybrids In Western Kenya, Charles A.O. Midega, John Pickett, Antony Hooper, Jimmy Pittchar, Zeyaur R. Khan

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Production of maize in western Kenya is severely constrained by the parasitic weed striga. Although productivity of maize can be improved through adoption of improved varieties, adoption of such varieties remains low in the region, as the majority of smallholder farmers still grow unimproved open-pollinated varieties (landraces). The performance of two improved hybrid varieties was evaluated against six landraces in striga-infested soils in western Kenya. The varieties were planted in plots under natural striga infestation and were supplemented with pot experiments under artificial infestation. Striga emergence was lower in landraces than in the hybrid varieties in both field and pot …

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Spatial Separation Of Semiochemical Lurem-Tr And Entomopathogenic Fungi To Enhance Their Compatibility And Infectivity In An Autoinoculation System For Thrips Management, David K. Mfuti, Sevgan Subramanian, Rob Whm Van Tol, Gerrie L. Wiegers, Willem J. De Kogel, Saliou Niassy, Hannalene Du Plessis, Sunday Ekesi, Nguya K. Maniania Jan 2016

Spatial Separation Of Semiochemical Lurem-Tr And Entomopathogenic Fungi To Enhance Their Compatibility And Infectivity In An Autoinoculation System For Thrips Management, David K. Mfuti, Sevgan Subramanian, Rob Whm Van Tol, Gerrie L. Wiegers, Willem J. De Kogel, Saliou Niassy, Hannalene Du Plessis, Sunday Ekesi, Nguya K. Maniania

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BACKGROUND: The effect of spatial separation of the semiochemical Lurem-TR, which has been found to inhibit conidia of entomopathogenic fungi when put together, on the persistence of conidia of Metarhizium brunneum and M. anisopliae was evaluated in the greenhouse and field in order to develop an autodissemination strategy for the management of Megalurothrips sjostedti on cowpea crop. Influence of spatial separation of the semiochemical on thrips attraction and conidial acquisition by thrips from the autoinoculation device was also investigated in the field. RESULTS: Persistence of conidia of M. brunneum and M. anisopliae increased with distance of separation of Lurem-TR. Direct …

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Mitochondrial Coding Genome Analysis Of Tropical Root-Knot Nematodes (Meloidogyne) Supports Haplotype Based Diagnostics And Reveals Evidence Of Recent Reticulate Evolution, Toon Janssen, Gerrit Karssen, Myrtle Verhaeven, Danny Coyne, Wim Bert Jan 2016

Mitochondrial Coding Genome Analysis Of Tropical Root-Knot Nematodes (Meloidogyne) Supports Haplotype Based Diagnostics And Reveals Evidence Of Recent Reticulate Evolution, Toon Janssen, Gerrit Karssen, Myrtle Verhaeven, Danny Coyne, Wim Bert

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The polyphagous parthenogenetic root-knot nematodes of the genus Meloidogyne are considered to be the most significant nematode pest in sub-tropical and tropical agriculture. Despite the crucial need for correct diagnosis, identification of these pathogens remains problematic. The traditionally used diagnostic strategies, including morphometrics, host-range tests, biochemical and molecular techniques, now appear to be unreliable due to the recently-suggested hybrid origin of root-knot nematodes. In order to determine a suitable barcode region for these pathogens nine quickly-evolving mitochondrial coding genes were screened. Resulting haplotype networks revealed closely related lineages indicating a recent speciation, an anthropogenic-aided distribution through agricultural practices, and evidence …

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Impact Of Reduced Tillage And Crop Residue Management On Soil Properties And Crop Yields In A Long-Term Trial In Western Kenya, Jeremiah M. Okeyo, Jay Norton, Saidou Koala, Boaz Waswa, Job Kihara, Andre Bationo Jan 2016

Impact Of Reduced Tillage And Crop Residue Management On Soil Properties And Crop Yields In A Long-Term Trial In Western Kenya, Jeremiah M. Okeyo, Jay Norton, Saidou Koala, Boaz Waswa, Job Kihara, Andre Bationo

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Sustainable farming practices are required to address the persistent problems of land degradation and declining crop productivity in Sub-Saharan Africa. Approaches such as reducing tillage and retaining crop residues as mulch are potential entry points for smallholder farmers to move towards sustainability. In this study, we assessed the impact of reduced tillage (RT) compared with conventional tillage (CT), each combined with crop residue reapplication, on soil quality indicators and crop yields under an 8-year trial in western Kenya. Our results indicate that RT combined with crop residue reapplication enhanced soil physical quality through increased macroaggregate (>2000μm) proportions and mean …

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Eco-Friendly Nets To Improve Vegetable Production And Quality In Sub-Saharan Africa, T. Martin, S. Simon, L. Parrot, F. Assogba Komlan, F. Vidogbena, A. Adegbidi, V. Baird, M. Saidi, M. Kasina, L. A. Wasilwa, S. Subramanian, M. Ngouajio Dec 2015

Eco-Friendly Nets To Improve Vegetable Production And Quality In Sub-Saharan Africa, T. Martin, S. Simon, L. Parrot, F. Assogba Komlan, F. Vidogbena, A. Adegbidi, V. Baird, M. Saidi, M. Kasina, L. A. Wasilwa, S. Subramanian, M. Ngouajio

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Continuous coverage of vegetables with nets under different climate conditions in Benin and Kenya proved effective in protecting vegetable nurseries and main fields against key lepidopteran and dipteran pests. However, netting did not effectively protect the vegetables against small insects such as aphids and whiteflies, although a visual barrier could delay outbreaks. Hence, opening the nets during the day could be an alternative option to conserve the natural enemies for small insects. Moreover, the efficacy of the visual barrier may be complemented by a repellent compound impregnated in the net. The small-holder growers adopting the nets in Benin and Kenya …

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Cost: Benefit Analysis Of Insect Net Use In Cabbage In Real Farming Conditions Among Smallholder Farmers In Benin, Faustin Vidogbéna, Anselme Adégbidi, Françoise Assogba-Komlan, Thibaud Martin, Mathieu Ngouajio, Serge Simon, Rigobert Tossou, Laurent Parrot Dec 2015

Cost: Benefit Analysis Of Insect Net Use In Cabbage In Real Farming Conditions Among Smallholder Farmers In Benin, Faustin Vidogbéna, Anselme Adégbidi, Françoise Assogba-Komlan, Thibaud Martin, Mathieu Ngouajio, Serge Simon, Rigobert Tossou, Laurent Parrot

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Insect net use provides a physical exclusion of pests as well as a microclimate change, thus increasing soil humidity, vegetable quality and yields in tropical conditions. This paper presents the findings of a cost:benefit analysis of this technology in real farming conditions compared to current insecticide practices. The surveys were conducted in Benin for cabbage production (. Brassica oleracea L.) during two production cycles. There were almost no significant differences in costs between unnetted and netted cabbage for the two production cycles. The only factors that varied were farm gate prices, the number of cabbages marketed and their size. Improved …

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Characteristics Of Soils In Selected Maize Growing Sites Along Altitudinal Gradients In East African Highlands, Elijah Njuguna, Mary Gathara, Stanley Nadir, Sizah Mwalusepo, David Williamson, Pierre Etienne Mathé, Jackson Kimani, Tobias Landmann, Gerald Juma, George Ong'amo, Erastus Gatebe, Bruno Le Ru, Paul André Calatayud Dec 2015

Characteristics Of Soils In Selected Maize Growing Sites Along Altitudinal Gradients In East African Highlands, Elijah Njuguna, Mary Gathara, Stanley Nadir, Sizah Mwalusepo, David Williamson, Pierre Etienne Mathé, Jackson Kimani, Tobias Landmann, Gerald Juma, George Ong'amo, Erastus Gatebe, Bruno Le Ru, Paul André Calatayud

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Maize is the main staple crop in the East African Mountains. Understanding how the edaphic characteristics change along altitudinal gradients is important for maximizing maize production in East African Highlands, which are the key maize production areas in the region. This study evaluated and compared the levels of some macro and micro-elements (Al, Ca, Fe, K, Mg, Mn, Na and P) and other soil parameters (pH, organic carbon content, soil texture [i.e. % Sand, % Clay and % Silt], cation exchange capacity [CEC], electric conductivity [EC], and water holding capacity [HC]). Soil samples were taken from maize plots along three …

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Effects Of Agroforestry On Pest, Disease And Weed Control: A Meta-Analysis, Lorena Pumariño, Gudeta Weldesemayat Sileshi, Sofia Gripenberg, Riikka Kaartinen, Edmundo Barrios, Mary Nyawira Muchane, Charles Midega, Mattias Jonsson Nov 2015

Effects Of Agroforestry On Pest, Disease And Weed Control: A Meta-Analysis, Lorena Pumariño, Gudeta Weldesemayat Sileshi, Sofia Gripenberg, Riikka Kaartinen, Edmundo Barrios, Mary Nyawira Muchane, Charles Midega, Mattias Jonsson

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Agroforestry practices may influence pest incidence and abundance both through increased top-down regulation by natural enemies and via bottom-up factors such as moderation of microclimate, soil nutrients and water content. We conducted a meta-analysis of the effects of agroforestry on the abundance of invertebrate pests, weeds, natural enemies and plant damage due to pests and diseases. We also tested whether effects of agroforestry were dependent on crop type (annual or perennial), type of pest association (above or belowground) and weed type (parasitic Striga weeds or non-parasitic weeds).Agroforestry practices resulted in lower abundances of both parasitic and non-parasitic weeds, and in …

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The Biosynthesis Of Allelopathic Di-C-Glycosylflavones From The Roots Of Desmodium Incanum (G. Mey.) Dc, Bing Hao, John C. Caulfield, Mary L. Hamilton, John A. Pickett, Charles A.O. Midega, Zeyaur R. Khan, Junru R. Wang, Antony M. Hooper Oct 2015

The Biosynthesis Of Allelopathic Di-C-Glycosylflavones From The Roots Of Desmodium Incanum (G. Mey.) Dc, Bing Hao, John C. Caulfield, Mary L. Hamilton, John A. Pickett, Charles A.O. Midega, Zeyaur R. Khan, Junru R. Wang, Antony M. Hooper

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The allelopathic root exudate of the drought-tolerant subsistence cereal intercrop D. incanum, protecting against the parasitic weed Striga hermonthica, comprises a number of di-C-glycosylflavones specifically containing C-glucosyl, C-galactosyl and C-arabinosyl moieties. Here we demonstrate that the biosynthesis of all compounds containing a C-glucose involves C-glucosylation of 2-hydroxynaringenin with subsequent C-galactosylation, C-glucosylation or C-arabinosylation. In addition, the crude soluble enzyme extract converts two fluorinated 2-hydroxyflavanone analogues to corresponding mono- and di-C-glycosylflavones demonstrating that some differences in C-ring substitution can be tolerated by the plant enzymes. Elucidating the biosynthesis of these C-glycosylflavones (CGFs) has the potential to open up opportunities for transferring …

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Evaluating The Sequential Masking Classification Approach For Improving Crop Discrimination In The Sudanian Savanna Of West Africa, Gerald Forkuor, Christopher Conrad, Michael Thiel, Tobias Landmann, Boubacar Barry Oct 2015

Evaluating The Sequential Masking Classification Approach For Improving Crop Discrimination In The Sudanian Savanna Of West Africa, Gerald Forkuor, Christopher Conrad, Michael Thiel, Tobias Landmann, Boubacar Barry

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Classification of remotely sensed data to reveal the spatial distribution of crop types has high potential for improving crop area estimates and supporting decision making. However, remotely sensed crop maps still demand improvements as e.g. variations in farm management practices (e.g. planting and harvesting dates), soil and other environmental factors cause overlaps in features available for classification and thus confusion in error matrices. In this study, a variant of the sequential masking classification technique was applied to multi-temporal optical and microwave remote sensing data (RapidEye, Landsat, TerraSAR-X) to improve the accuracy of crop discrimination in West Africa. This approach employs …

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