Spread of Xanthomonas vasicola pv. musacearum within banana mats: implications for Xanthomonas wilt management
Xanthomonas wilt (XW) of banana caused by Xanthomonas vasicola pv. musacearum (Xvm) does not spread to all plants physically interconnected through the rhizome when one or a few are diseased. However, the factors behind this incomplete systemic spread of Xvm are not fully known yet could inform XW management. This study explored the effect of Xvm inoculum amounts, number and size of suckers, sucker positioning on mother plant corms and other mother plant corm attributes on sucker colonization.
... shorter (p <0.05) incubation period (17.9 vs 21.1 days) and higher (p<.001) cumulative number of symptomatic leaves (5.2 vs 1.6 leaves) was observed when all (high inoculum) compared to two leaves (low inoculum) were inoculated. Xvm was recovered in corms at 29 days post inoculation (dpi) in both treatments with no differences (p >0.05) in proportions of corms with Xvm between the treatments. However, Xvm was recovered earlier and at a higher frequency in suckers when all leaves were inoculated. Lower Xvm recoveries occurred in the lower corm sections to which most suckers were attached relative to the middle and upper corm sections. Xvm incidence in corms increased with the number of attached maiden suckers, and the dpi while it declined with increasing mother plant and corm height. Thus, Xvm spread within mats is influenced by the amount of inoculum and the physiological stage (e.g., height) of the plant and attached suckers. The position of suckers, predominantly at the bottom of corms also protects them from infection. Measures that reduce Xvm inoculum build-up in mats are thus crucial for minimizing within mat XW spread.