Farm management practices and-their effects on yield, disease incidence and pest density of·banana and groundnut in western Kenya: planting density, intercropping and banana weevil Cosmopolites sordidus Germar (Gleoptera: Curculionidae) trapping

Abstract

Studies on the effects of pseudostem trapping, plant density and intercropping on the banana weevil Cosmopolites sordidus Germar. populations and crop yields were conducted in western Kenya from 1994 to 1997. The objective of the investigation was to explore the efficacy of non-pesticidal options for the management of banana weevil. Field experiments were conducted using clean planting material, pseudostem traps for weevil management and intercropping banana with groundnuts, Arachis hypogaea L. in two different banana densities. Results indicate that at low weevil population density, pseudostem traps significantly reduced the number of adult weevils. It suppressed weevil population increase and reduced the level of damage caused to the crop. Though intercropping banana with groundnuts did not prevent weevils from colonizing the banana, it influenced their distribution during the early growth stages of the banana. Banana crops planted at 3x 3 m and 5x 5 m spacing did not affect the growth of groundnuts during the first year. However, beyond this period, the banana canopy significantly reduced the growth oftlle groundnuts, which were intercropped within the 3x5 m banana spacing. \Nevertheless, spacing significantly influenced the banana yield per unit area. Thus under the 3x3 m banana spacing, yields were more comparable with the 5x5 m banana spacing. Competition for growth factors was first experienced in the banana at 3x3 m under the groundnut intercrop after three gr.~ing seasons. The number of flower thrips, aphids, and groundnut rosette virus were relatively reduced in the banana intercrop compared to those in the groundnut monocrop.