Enhancement of control by nutrient formulations of selected biocontrol agents against fusarium crown and root rot of tomato

O. Ibrahim and S. Rossall

Abstract

Two bacterial isolates identified as Bacillus megaterium c96 and Pseudomonas cepacia c91 were used in this study to investigate the effect of nutrient amendment in the biocontrol formulation. Both isolates were obtained from screening works conducted in the research programme for the control of Fusarium crown and root disease of tomato. The use of 1% or 10% concentrations of YPG (yeast, peptone, glucose) liquid medium in the biocontrol formulation did not enhance the biocontrol activity of both isolates. However, when these nutrient sources were prepared individually, yeast was found significantly (p = 0.01) enhancing the biocontrol activity of P. cepacia c91 but was less effective with B. megaterium c96. Similar results were obtained when the formulation was tested under long-term experiment. The effects of Fe, Mg and Zn were examined and the results indicated that the bacterial biocontrol agents responded positively to the addition of Mg and Fe with significant reduction in the percentage of disease infection but Zn shows some deleterious effect on both isolates tested.

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