Abstract

Trichoderma harzianum and Bacillus brevis were tested separately and in combination against infection of Tuberose bulbs by F. oxysporum f. sp. tuberose in soilless culture using Perlite as the substrate. The efficiency of both of antagonists against bulb rot was evaluated based on vegetative and root growth parameters and on flowering parameters. T. harzianum effectively suppressed disease and also enhanced plant growth, leading to increased flower production and quality. Bacillus brevis enhanced plant growth when tested alone. The mixture of antagonists reduced the effectiveness of T. harzianum in disease control. Numbers of T. harzianum colony-forming units (CFU) in the substrate and on bulbs were higher when applied alone compared with treating with both antagonists. No T. harzianum was detected in the substrate by 120 day after planting. Bacillus brevis CFU recovered from bulbs were lower when inoculated in combination with T. harzianum and F. oxysporum f. sp. tuberosi. However, Bacillus brevis CFU were not detected in the substrate of bulbs treated with both T. harzianum and Bacillus brevis and inoculated with F. oxysporum f. sp. tuberosi. It was concluded that T. harzianum provided an efficient and effective control of F. oxysporum f. sp. tuberosi bulb rot of Tuberose plants.

Keywords: Tuberose; Trichoderma harzianum; Aneurinibacillus migulanus; F. oxysporum; f. sp. tuberosi; Soilless culture; CFU