The RLH was significantly reduced by the antagonists as compared with the control. Among the isolates, T. harzianum AS12-2 resulted in the lowest RLH and disease severity, and was therefore the most effective, as effective as propiconazole. Nine other T. harzianum and three T. virens isolates also restricted disease lesions to less than 30% of plant height (scale 3). The single T. atroviride isolate was ineffective in this assay. Twenty other Trichoderma isolates formed part of the same group as the control inoculated with the pathogen, and were therefore also completely ineffective.