ESTABLISHMENT OF A BIOASSAY FOR TESTING CONTROL MEASURES AGAINST CROWN ROT OF BANANA

Two assessment methods for crown rot were compared: the widely used, c ategorical 0-5 scale and depth of rot penetration. Both were very high ly correlated; the latter was more sensitive. The development of a bio assay for testing for crown rot pathogens and control methods is descr ibed. The rotting of green peel disks dipped in spore suspensions was significantly correlated with crown rot progress of whole clusters for both highly pathogenic C. musae and weakly pathogenic F. moniliforme isolates using inoculum concentrations covering a range of five orders of magnitude. The bioassay is specific to crown rot pathogens and det ects efficient control measures. Because it is reliable, simple and ra pid, it is suggested as a routine pre-screen for biocontrol agents aga inst crown rot. The steps required for the establishment of a represen tative bioassay are explained and the final, optimised practical proto col is described. Crown copyright (C) 1996 Published by Elsevier Scien ce Ltd.