The development of an early evaluation method for host response of different Musa clones to black sigatoka was investigated under natural inoculation conditions in southeastern Nigeria. Two months old tissue-culture-derived plants of three plantain hybrids and parents of the hybrids were exposed to the natural inoculum of Mycosphaerella fijiensis in a field planted with a susceptible plantain cultivar. The response to M. fijiensis was evaluated on these young plants and on the same clones of mature, ...

Banana-weevil populations and associated damage were studied in adjacent plantations of highland cooking-bananas (cultivar Kibuzi) and introduced beer-bananas (cv. Kisubi) on a farm in central Uganda. Weevil density and mobility were assessed using mark and rerapture techniques. Residual banana corms and pseudostems were evaluated for weevil damage at various intervals following harvest. Newly harvested cooking-bananas revealed moderate weevil damage that reached the corm centre, whereas damage ...

Four research programmes are investigating the entomopathogenic fungal genera Metarhizium and Beauveria for locust and grasshopper control in Africa. In the LUBILOSA programme, surveys for pathogen isolates revealed a morphologically distinctive Metarhizium flavoviride Gams and Rozsypal attacking acridoids in West Africa, Madagascar, and elsewhere. Metarhizium anisopliae (Metschnikoff) Sorokin isolates with virulence to acridoids were also obtained, including several from non-orthopteran hosts. ...

Intensification of agriculture in the tropics has resulted from a shortage of farmland and insufficient food production to satisfy the needs of an expanding population. Many tropical farmers are challenged by the prospect of intensifying their production while sustaining or improving the fertility and productivity of soils with only locally available natural resources. The waste products of plant and animal production represent some of the most abundant natural resources available for use by ...

Seed treatments with two acetolactate synthase (ALS)-inhibiting herbicides, the sulfony- lurea herbicide nicosulfuron and the imidazolinone herbicide imazaquin, controlled the parasitic weed Striga hermonthica in corn. The XA-17 gene in ALS-modified P3180IR corn strongly reduced corn injury from herbicide seed treatments while another ALS modification was not effective. Combining seed treatment of ALS-inhibiting herbicides and ALS-modified corn with the XA-17 gene may offer a practical means for ...

The restorative ability of herbaceous (Psophocarpus palustris, Pueraria phaseoloides) and woody (Leucaena leucocephala, Senna siamea, Acacia leptocarpa, Acacia auriculiformis) legume species and of natural regrowth was studied on an eroded and compacted Oxic Paleustalf in southwestern Nigeria. Compared to the control treatment that was continuously cropped for 15 years, four years of fallowing significantly improved test crop yields. However, fallowing with the above species did not substantially ...

Research institutes in Africa have had limited success in producing new technologies appropriate to the needs of small farmers because of an inadequate understanding of small farmers' goals and resource limitations and over-reliance on the transfer of technologies from other regions. Farming systems research (FSR) is an effective way of improving the focus of scientists on the problems farmers face. Vertically segmented thematic research programmes make institutionalization of FSR difficult within ...

Trees can influence both the supply and availability of nutrients in the soil. Trees increase the supply of nutrients within the rooting zone of crops through (1) input of N by biological N2 fixation, (2) retrieval of nutrients from below the rooting zone of crops and (3) reduction in nutrient losses from processes such as leaching and erosion. Trees can increase the availability of nutrients through increased release of nutrients from soil organic matter (SOM) and recycled organic residues. Roots ...

Budgets for palm-oil and palm-alcohol production were constructed to show the economic benefit of each activity to smallholder farmers in southern Benin. The selling prices of oil palms to alcohol distillers, who cut the trees, were approximately equal to the annual fruit revenue for that tree. Since trees produce fruit for several decades, this price seems very low. A life-table analysis of the trees was conducted after converting tree height to tree age and substituting revenue for offspring. ...