Use of pseudostem traps and coefficient of infestation (PCI) for assessing banana infestation and damage by Cosmopolites sordidus germar

Abstract

Infestation and damage by Cosmopolites sordidus are usually assessed by pseudostem trapping of adults and determination of the percent coefficient of infestation (PCI), a measure of external signs of tunnelling in rhizomes. To investigate the deficencies of this method, experiments were carried out in 1991 near Kampala, and sampling of bananas took place the same year in Mpigi and Masaka, in Central Uganda. Variation in trap length, site, duration of trapping and soil moisture conditions significantly influenced catches of C. sordidus in pseudostem traps. The relationship between PCI and internal rhizome damage by C. sordidus varied between banana types and with the parameters used to quantify damage. There was a poor correlation between trap catches and rhizome damage.