Efficacy of Rhizobacteria and Humic Acid for Controlling Fusarium Wilt Disease and Improvement of Plant Growth, Quantitative and Qualitative Parameters in Tomato

Abstract

The effect of tomato seedling treated with plant growth promoting rhizobacteria (PGPR) strains viz. Azotobacter sp. (AZM1),Bacillus cereus (BCM8), B. megaterium (BMM5) individually or combined with humic acid were evaluated for controlling wilt disease caused by Fusarium oxysporum f. sp. lycopersici, plant growth, fruit quantitative and qualitative (cv. Super Strain-B) during 2010-2011 and 2011-2012 growing seasons. Under greenhouse conditions, all treatments significantly reduced area under disease progress curve (AUDPC) and increased plant height, fresh and dry weights of survival plants growing in pots infested with the causal pathogen compared with control. Combination treatments of humic acid with PGPR reduced significantly wilt incidence and increased plant height, fresh and dry weights of tomato plants comparing with the application of each of them alone. Under laboratory conditions, all PGPR strains and humic acid able to inhibited leaner growth of the causal pathogen with different degrees and PGPR strains were more active than humic acid in this respect.  Under field conditions, all PGPR stains individually or combined with humic acid significantly reduced AUDPC and improved plant growth (plant height, number of branches plant -1) quantitative (number of fruits plant  -1, fruit weight plant -1, fruit weight, fruit yield fed.  -1, Number of fruit Kg  -1) and qualitative (degree of   fruit’s color, fruit diameters, firmness, fruit height, total soluble solids) parameters of tomato fruits compared with untreated plants (control) in both growing seasons. Combination treatments of humic acid with PGPR strains increase the effectiveness of them in this respect  more than   used alone.