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Journal and Journal Articles: Recent submissions
Now showing items 2121-2140 of 5273
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Spatial dynamics of lepidopterous pests on Zea mays (Linnaeus) and Pennisetum purpureum (Moench) in the forest zone of Cameroon and their implications for sampling schemes
(2001)common lepidopterous borers attacking maize and/or the wild host Penni.l'etum purpureum in the forest zonc of Camcroon arc the noctuids Buss('ola.li/sca (Fuller), Sesamia calamistis (Hampson) and Poeol1oma serrata (Hampson), the pyralids Eldani! s{{cc/wrin{{ (Walker) and Mus.l'idia nigrivel1ella (Ragonot), and Cryptophlehia leucotreta (Tortricidae). The within-plant distribution on maize and elephant grass was studied for the predominant species B . .Iil.\·('(l, and on maize only for E. s{{ccharilla ... -
Distribution, relative importance and effect of lepidopterous borers on maize yields in the forest zone and midaltitude of Cameroon
(2001-12-01)Geographic distribution, relative importance, and effect of lepidopterous stem and ear borers on maize, Zea mays L., were studied in the humid forest and the mid-altitude zones of Cameroon from 1994 to 1997. Six villages were chosen in the forest zone and grouped into three blocks representing gradients in human population density. A single block with three villages was chosen in the mid-altitude. Farmers’ maize fields were surveyed during the vegetative growth phase for Busseola fusca (Fuller) ... -
The effects of an entomopathogenic fungus, Beauveria bassiana (Balsamo) Vuillemin (Hyphomycetes), on Prostephanus truncatus (Horn) (Col: Bostrichdae), Sitophilus zeamais (Col: Curculionidae) and grain losses in stored maize in the Benin Republic
(2001-04)A fungal entomopathogen, Beauveria bassiana, was used to treat maize ears placed in traditional grain stores against Prostephanus truncatus in a field experiment conducted from September 1997 to March 1998 in the Benin Republic, West Africa. Treatments included oil-based spray with and without conidia, maize stored with and without the husk, and stores with and without artificial infestation. Additional treated ears kept in insect-proof cages under field conditions were sampled weekly and exposed ... -
Successional sequence of forest types in a disturbed dry forest reserve in southern Benin, West Africa
(2001-07-01)Human pressure on forest resources in southern Benin has led to a dramatic reduction and disturbance of natural forest patches. The largest remaining forest reserve in southern Benin is the Lama forest, which is known to be a reserve for many endangered species and situated in the boundary between dry forest and savanna. From cluster analysis and hierarchical classification of tree species composition, five forest types were identified in the Lama forest, and ordination techniques were used to ... -
Natural enemies of lepidopterous borers on maize and elephant grass in the forest zone of Cameroon
(2001-06)The importance, geographical and temporal distributions of parasitoids of lepidopterous borers on maize and elephant grass, Pennisetum purpureum, were assessed during surveys in farmers’ fields in six villages and two on-station trials in the forest zone of Cameroon between 1995 and 1996. The borer species encountered were Busseola fusca (Fuller), Sesamia calamistis Hampson, Eldana saccharina Walker on both host plants, and Mussidia nigrivenella Ragonot on maize only. Busseola fusca was the ... -
Biological control of the cassava mealybug in Africa: a review
(2001-07)Among several natural enemies introduced to combat the cassava mealybug, Phenacoccus manihoti (Homoptera: Pseudococcidae), the neotropical parasitoid Apoanagyrus (Epidinocarsis) lopezi (Hymenoptera: Encyrtidae) was the most successful. It established in 26 African countries, causing a satisfactory reduction in the population density of P. manihoti in most farmers' fields. Four conclusions concerning the possible application of the research results to other biological control projects are discussed. ... -
Allozyme polymorphism in tetraploid potato gene pools and the effect of human selection
(2001-10)The need for broadening a crop’s genetic base may be determined by comparing allele frequencies within the gene pools of farmer selections in their centers of diversity with that of modern breeding populations. The genetic structure of Andean and Chilean potato farmer selections was investigated with the aid of nine isozymes, which have been studied in detail and used to characterize North American cultivars and advanced breeding lines. These isozymes are associated with the most-important agronomic ... -
Fungal infection and mycotoxin contamination of maize in the humid forest and the western highlands of Cameroon
(2001-08)Fungal incidence and mycotoxin contamination of farm-stored maize were assessed and compared in grain samples from three villages each in two agroecological zones over time. Maize samples were collected at 2 and 4 months after stocking from 72 farmers’ stores in 1996 and 1997 in the Humid Forest (HF) and Western Highlands (WHL) of Cameroon. Mycological assays of these samples revealed several fungal species.Nigrospora spp. were the most prevalent fungi in HF (32%) and WHL (30%) in 1996,Fusarium ... -
Seasonal fluctuations of noctuid stemborer egg parasitism in southern Benin with special reference to Sesamia calamistis Hampson (Lepidoptera:Noctuidae) and Telenomus spp (Hymenoptera:Scelionidae) on maize
(2001)Parasitism of noctuid stemborer eggs was assessed in monthly surveys in maize fields in southern Benin, from May 1995 to October 1996, and on alternative hosts, i.e. wild grasses, during the dry season from November 1995 to February 1996. Sesamia calamistis was the most prevalent stemborer species, accounting for 98% of the larvae identified from subsamples reared on ear pieces. Egg batch densities ranged between 0.02-0.15 per plant, with lowest densities found during high rainfall periods. 77% ... -
Multiple purpose tree use by farmers using indigenous knowledge in subhumid and semiarid northern Nigeria
(2001)The northern Guinea savanna is generally known to be suitable for the production of annual crops of short-to-medium duration but is threatened with soil degradation because of inadequate organic inputs. Trees can be one important source of organic supplement to crop fields. Farmers' preferences for trees are related to a myriad of needs which vary in different environments. A survey was undertaken in Bauchi and Kaduna States of northern Nigeria to determine the extent of farmer knowledge in ... -
Litter and biomass production from planted and natural fallows on a degraded soil in southwestern Nigeria
(2001-03)To rehabilitate a degraded Alfisol at Ibadan, southwestern Nigeria, Senna siamea (non-N-fixing legume tree), Leucaena leucocephala, and Acacia leptocarpa (N-fixing legume trees) were planted in 1989, and Acacia auriculiformis (N-fixing legume tree) in 1990. Pueraria phaseoloides (a cover crop) and natural fallow were included as treatments. Litterfall and climatic variables were measured in 1992/1993 and 1996/1997 while biomass production and nutrient concentrations were measured in 1993 and 1995. ... -
Silver staining of Musa chromosomes
(2001)Cytological studies in Musa spp. L. are hampered by the small size and poor staining ability of the chromosomes. The aim of this experiment was to use silver nitrate as a staining agent for Musa chromosomes. The results of this study showed that silver nitrate is a useful alternative stain for cytological studies in Musa. The silver staining procedure was very effective for demonstrating the structure of prophase stages of meiosis. -
Resistance to aflatoxin accumulation in kernels of maize inbreds selected for ear rot resistance in West and Central Africa
(2001-03)Thirty-six inbred lines selected in West and Central Africa for moderate to high resistance to maize ear rot under conditions of severe natural infection were screened for resistance to aflatoxin contamination using the previously established kernel screening assay. Results showed that more than half the inbreds accumulated aflatoxins at levels as low as or lower than the resistant U.S. lines GT-MAS:gk or MI82. In 10 selected aflatoxin-resistant or aflatoxin-susceptible inbreds, Aspergillus flavus ... -
Maternal inheritance of chloroplast DNA in interspecific crosses of Bromus
(2001-03)Inheritance of chloroplast DNA (cpDNA) was examined in 41 F1 progeny obtained from the following interspecific Bromus crosses: Bromus arvensis (2n = 14) × B. inermis (2n = 4x = 28); B. arvensis × B. inermis (2n = 8x = 56); B. arvensis × B. erectus (2n = 6x = 42); B. arvensis × B. erectus (2n = 8x = 56); B. arvensis × B. erectus (2n = 10x = 70). Chloroplast DNA of the parental species was digested with BamHI, EcoRI and HindIII and species-specific restriction fragment length polymorphisms were ... -
Influence of different fallow management systems on stability of soil aggregates in southern Nigeria
(2001)The effects of different fallow management systems on aggregate stability were studied on an Ultisol and an Alfisol in southern Nigeria. Aggregate stability was measured in natural regrowth, and planted fallows of Pueraria phaseoloides Benth. and Leucaena leucocephala Lam de Wit in a trial established in 1989 on an Alfisol at Ibadan (7°30′N, 3°54′E), southwestern Nigeria. Soil samples (0–30 cm depth at this instance) were wetted by immersion for 2 and 10 minutes before wet-sieving at 30 rpm for 5 ... -
Nematodes associated with East African Highland cooking bananas and cv. Pisang Awak (Musa spp.) in Central Uganda
(2001)A survey was conducted at 17 sites in Central Uganda. Suckers were detached from East African Highland cooking bananas (Musa spp., AAA-group) and the cultivar Pisang Awak (Musa spp., ABB-group), and assessed for nematode population densities and root damage. The frequency of occurrence on both Musa groups was Helicotylenchus multicinctus 88%, Radopholus similis 74% and Pratylenchus goodeyi 50%. Helicotylenchus multicinctus and R. similis densities were higher (P ≤ 0.05) on Highland cooking bananas ... -
Need for consistency in Nigerias agricultural development policy and programmes
(1985)Consistency in agricultural development policy and programs is tantamount to adherence to guiding principles (policy), strategies or tactics and programs that are compatible with the nature of agriculture, problems to be solved and objectives desired. Based on the location specificity of agricultural production as bio-economic activity, defined as the science, business and art of growing crops and rearing animals to satisfy man's need for food, miscellaneous products and objectives, consistency ... -
Sustainable resource management coupled to resilient germplasm to provide new intensive cerealgrainlegumelivestock systems in the dry savanna
(2003-12)Sustainable resource management is the critical agricultural research and development challenge in sub-Saharan Africa. The accumulated knowledge on soil management gathered over the last 10 years, combined with solid crop improvement and plant health research at farmers’ level, has brought us to a stage where we can now address with confidence the intensification of cereal–grain–legume-based cropping systems in the dry savanna of West Africa in a sustainable and environmentally positive manner. ... -
An automated enzymatic assay for determining the cyanide content of cassava (Manihot esculenta) and cassava products
(1984)An automated enzymic method for the analysis of cyanide in cassava and cassava products is described. A total of 300 analyses a day can be handled easily. A wide range of free (nonglycosidic) or bound (cyano‐substituted glycosides) cyanides (0.4–40 μg HCN ml−1) can be assayed in the extracted solutions. The upper limit of detection for the bound cyanide can easily be increased by another three‐fold by assaying it under partial hydrolysis conditions. The two enzymic methods, manual and automated ... -
Rhizobium host specificities in phaseolus coccineus L. and phaseolus vulgaris L.
(1982)The introduction of desirable agronomic characteristics into Phaseolus vulgaris L. is being attempted by interspecific hybridization with P. coccineus, but the effects on root nodulation are unknown. Accordingly, cross-inoculation relationships between P. vulgaris ‘Red Kidney’ and P. coccineus ‘Scarlet Runner’ were tested in the greenhouse with a group of 16 Rhizobium strains effective on Red Kidney and a group of 12 strains effective on Scarlet Runner. Both groups had diverse origins, including ...
