Now showing items 621-640 of 5157

    • Temperature-dependent development, survival and reproduction of Apanteles hemara (Nixon) (Hymenoptera: Braconidae) on Spoladea recurvalis (F.) (Lepidoptera: Crambidae) 

      Agbodzavu, M.K.; Osiemo-Lagat, Z.; Gikungu, M.; Ekesi, S.; Fiaboe, K.K.M. (2020-02-18)
      The temperature-dependent development of Apanteles hemara (Nixon), a larval endoparasitoid of the devastating amaranth pest Spoladea recurvalis (F.) was studied in the laboratory at six constant temperatures (10, 15, 20, 25, 30 and 35 °C), a photoperiod of 12L:12D and a relative humidity of 60–70%. Developmental time decreased significantly with increasing temperature within the range of 15–30 °C. The parasitoid's pupal mortality, successful parasitism rate, adult emergence rate and longevity, sex ...
    • Plant tissue analysis as a tool for predicting fertiliser needs for low cyanogenic glucoside levels in cassava roots: an assessment of its possible use 

      Imakumbili, M.L.; Semu, E.; Semoka, J.M.; Abass, A.; Mkamilo, G. (2020-02-13)
      The use of plant tissue analysis as a tool for attaining low cyanogenic glucoside levels in cassava roots, has hardly been investigated. Just as the quality of crops is improved through the use of plant tissue analysis, the same can probably be done to consistently attain the lowest possible cyanogenic glucoside levels in cassava roots. High levels of cyanogenic glucosides in consumed fresh cassava roots or in their products have the potential of causing cyanide intoxication, hence the need to ...
    • Phenotypic characterization and validation of provitamin A functional genes in early maturing provitamin A-quality protein maize (Zea mays) inbred lines 

      Obeng‐Bio, E.; Badu‐Apraku, B.; Ifie, B.E.; Danquah, A.; Blay, E.T.; Dadzie, M.A. (2019)
      The number of drought and low‐N tolerant hybrids with elevated levels of provitamin A (PVA) in sub‐Saharan Africa could increase when PVA genes are optimized and validated for developed drought and low‐N tolerant inbred lines. This study aimed to (a) determine the levels of drought and low‐N tolerance, and PVA concentrations in early maturing PVA‐quality protein maize (QPM) inbred lines, and (b) identify lines harbouring the crtRB1 and LcyE genes as sources of favourable alleles of PVA. Seventy ...
    • Improving the efficiency of Beauveria bassiana applications for sustainable management of Plutella xylostella (Lepidoptera: Plutellidae) in West Africa 

      Agboyi, L.K.; Ketoh, G.K.; Kpindou, O.K.D.; Martin, T.; Glitho, I.A.; Tamὸ, M. (2020-05)
      The effectiveness of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin isolates Bb11, Bb115, Bb116 and Bb362 against the diamondback moth (DBM), Plutella xylostella (L.) population from Cotonou, Benin, was investigated in the laboratory and on station. In the laboratory, six concentrations, 104, 105, 106, 107, 108 and 109 conidia/ml of each isolate were used to assess B. bassiana virulence. Third instar DBM larvae were inoculated with 2 µl of each isolate’s concentrations by topical ...
    • Farm production diversity: is it important for dietary diversity? Panel data evidence from Uganda 

      Sekabira, H.; Nalunga, S. (2020-01-31)
      The substantial existence of malnutrition globally, especially in developing countries, has usually driven policy initiatives to focus on improving household food security and nutrition primarily through prioritizing farm production diversity. Although indeed some empirical evidence has pointed to farm production diversity remedying malnutrition, other evidence has pointed to markets. Therefore, evidence is mixed and may be country or region variant. To contribute to closing such a gap in the ...
    • Evaluating the distributional impacts of drought tolerant maize varieties on productivity and welfare outcomes: an instrumental variable quantile treatment effects approach 

      Olagunju, K.O.; Ogunniyi, A.I.; Awotide, B.A.; Adenuga, A.H.; Ashagidigbi, W.M. (2019-12-23)
      In an attempt to go beyond the conventional mean impact assessment of agricultural interventions, this paper examines the distributional impacts of adoption of drought-tolerant maize varieties (DTMVs) on the productivity and welfare outcomes of rural farming households in Nigeria. The study employed a conditional instrumental variable quantile treatment effects approach to control for selection bias that may arise from both observed and unobserved factors. The empirical findings revealed that ...
    • Efficient elimination of Yam mosaic virus (YMV) from white yam (Dioscorea rotundata Poir.) by cryotherapy of axillary buds 

      Ita, E.E.; Uyoh, E.A.; Nakamura, I.; Ntui, V.O. (2020-05)
      Dioscorea rotundata is an economically important food crop in many tropical countries as many people in this region depend on it for food and livelihood. Viral diseases, especially Yam mosaic virus (YMV), constitute a major constraint in the cultivation of this crop as they perpetuate through generations in the vegetatively propagated planting materials. Getting resistant or at least virus-free planting materials for farmers thus becomes crucial. This study was aimed at eliminating YMV in Dioscorea ...
    • Assessing the potential of extra-early maturing landraces for improving tolerance to drought, heat, and both combined stresses in maize 

      Nelimor, C.; Badu-Apraku, B.; Tetteh, A.Y.; Garcia-Oliveira, A.L.; N’guetta, A.S.P. (2020-02-25)
      Maize landrace accessions constitute an invaluable gene pool of unexplored alleles that can be harnessed to mitigate the challenges of the narrowing genetic base, declined genetic gains, and reduced resilience to abiotic stress in modern varieties developed from repeated recycling of few superior breeding lines. The objective of this study was to identify extra-early maize landraces that express tolerance to drought and/or heat stress and maintain high grain yield (GY) with other desirable ...
    • Application of predictive breeding in yam improvement for west Africa 

      Asfaw, A.; Aderonmu, S.D.; Norman, P.; Darkwa, K.; De Koeyer, D.; Agre, P.; Kouaku, A.; Chamba, E.; Otoo, E.; Obidiegwu, J.; Nwachukwu, E.; Dossou-Aminou, I.N.; Dansi, A.; Oselebe, H.; Adebola, P.; Asiedu, R. (2019)
    • A review of inclusive business models and their application in aquaculture development 

      Kaminski, A.M.; Kruijssen, F.; Cole, S.M.; Beveridge, M.C.; Dawson, C.; Mohan, C.V.; Suri, S.; Karim, M.; Chen, O.L.; Phillips, M.J.; Downing, W.; Weirowski, F.; Genschick, S.; Tran, N.; Rogers, W.; Little, D.C. (2020)
      For aquaculture to continue along its current growth trajectory and contribute towards achieving the Sustainable Development Goals, value chains must become more inclusive. Smallholders and other local value chain actors are often constrained by circumstances and market failures in the global aquaculture industry. Integrating these actors into aquaculture value chains through inclusive business models (IBMs) is often touted as a solution to sustainable and ethical trade and business that can ...
    • Genetic variability, stability and heritability for quality and yield characteristics in provitamin A cassava varieties 

      Peprah, B.B.; Parkes, E.; Manu-Aduening, J.; Kulakow, P.; van Biljon, A.; Labuschagne, M. (2020)
      Cassava is widely consumed in many areas of Africa, including Ghana, and is a major part of most household diets. These areas are characterized by rampant malnutrition, because the tuberous roots are low in nutritional value. Provitamin A biofortified cassava varieties have been developed by the International Institute for Tropical Agriculture, but adoption of these varieties in Ghana will largely depend on their agronomic performance, including fresh root yield, dry matter content, resistance to ...
    • Influence of larval density, substrate moisture content and feedstock ratio on life history traits of black soldier fly larvae 

      Dzepe, D.; Nana, P.; Fotso Kuate, A.; Tchuinkam, T.; Djouaka, R. (2019-12-13)
      Performance and body composition of insect larvae depend on quality and quantity of their diet, and on biotic factors such as larval density. Experiments were undertaken to assess the effects of larval density, substrate moisture content and feedstock ratio on larval life history parameters of black soldier fly (BSF) in the laboratory. Four-day-old larvae were separately reared under six different densities (1, 2, 4, 6, 8 and 10 larvae/cm2) and at five substrate moisture content levels (40, 50, ...
    • Land use decisions: by whom and to whose benefit? A serious game to uncover dynamics in farm land allocation at household level in northern Ghana 

      Michalscheck, M.; Groot, J.C.J.; Fischer, G.; Tittonell, P. (2019-12-17)
      Globally, 38% of the land area is agricultural land, of which 45% are located on drylands, mainly in Africa and Asia, constituting the basis for about 60% of the world’s food production. Of all farms worldwide, 83% are smallholder farm systems, whose livelihoods depend on effective land management and allocation. While land is often cultivated by the various members of a farm household, land allocation decisions depend on the approval, the ambition and the abilities of influential household members, ...
    • Classical biological control for the protection of natural ecosystems 

      Van Driesche, R.G.; Carruthers, R I.; Center, T.; Hoddle, M.S.; Hough-Goldstein, J.; Morin, L.; Smith, L.; Wagner, D.L.; Blossey, B.; Brancatini, V.; Casagrande, R.; Causton, C.E.; Coetzee, J.A.; Cuda, J.; Ding, J.; Fowler, S.V.; Frank, J.H.; Fuester, R.; Goolsby, J.; Grodowitz, M.; Heard, T.A.; Hill, M.P.; Hoffmann, J.H.; Huber, J.; Julien, M.; Kairo, M.T.K.; Kenis, M.; Mason, P.; Medal, J.; Messing, R.; Miller, R.; Moore, A.; Neuenschwander, P.; Newman, R.; Norambuena, H.; Palmer, W.A.; Pemberton, R.; Perez-Panduro, A.; Pratt, P.D.; Rayamajhi, M.; Salom, S.; Sands, D.; Schooler, S.; Schwarzländer, M.; Sheppard, A.; Shaw, R.; Tipping, P.W.; van Klinken, R.D. (2010-03-12)
      Of the 70 cases of classical biological control for the protection of nature found in our review, there were fewer projects against insect targets (21) than against invasive plants (49), in part, because many insect biological control projects were carried out against agricultural pests, while nearly all projects against plants targeted invasive plants in natural ecosystems. Of 21 insect projects, 81% (17) provided benefits to protection of biodiversity, while 48% (10) protected products harvested ...
    • Importance of biological control for tropical Africa 

      Neuenschwander, P. (2010)
      Though studies in biological control belong to the best documented research in ecology the actual decision to release a beneficial organism is often influenced by diffuse fears of anything foreign. Yet, agriculture is largely based on exotics; others remain inconspicuous and integrate themselves without problems into the existing ecosystems; and only few actually cause damage. It is against this latter group that the introduction of adapted predators from the region of origin, so-called classical ...
    • Cassava mealybug has reached Asia 

      Winotai, W.; Goergen, G.; Tamò, M.; Neuenschwander, P. (2010)
    • The functional responses of two Hyperaspis notata strains to their prey, the cassava mealybug Phenacoccus manihoti 

      Staubli Dreyer, B.; Baumgaertner, J.U.; Neuenschwander, P.; Dorn, S. (1997)
    • Insect invasions: the case of the cassava mealybug and its natural enemies evaluated 

      van Alphen, J.J.M.; Neuenschwander, P.; van Dijken, M.J.; Hammond, W.N.O.; Herren, H.R. (1989)
    • Biological control of the cassava mealybug Phenacoccus manihoti (Hom., Pseudococcidae) by Epidinocarsis lopezi (De Santis) (Hym., Encyrtidae) in West Africa, as influenced by climate and soil 

      Neuenschwander, P.; Hammond, W.; Ajuonu, O.; Gado, A.; Echendu, N.; Bokonon-Ganta, A.; Allomasso, R.; Okon, I. (1990)
      Population data concerning the cassava mealybug (CM) Phenacoccus manihoti Matile-Ferrero, the introduced parasitoid Epidinocarsis lopezi (De Santis), and indigenous antagonists were collected, together with ecological and plant growth variables, during a survey of 414 fields covering all ecological zones of Nigeria and Benin, for evaluation in multiple regression analyses. The choice of fields was unbiased, and insect populations were estimated from large random samples. Seven years after the first ...