Suppression of Fusarium Wilt of Banana with Application of Bio-Organic Fertilizers

Fusarium wilt is one of the most serious diseases of banana plants caused by soil-borne pathogen Fusarium oxysporum f.sp. cubense (FOC). In this study a pot experiment was conducted to evaluate the effects of different bio-organic fertilizers (BIOs) on Fusarium wilt of banana, including the investigations of disease incidence, chitinase and β-1,3-glucanase activities of banana plants, and FOC populations as well as soil rhizosphere microbial community. Five fertilization treatments were considered, including chemical fertilizer containing the same N, P and K concentrations as the BIO (control), and matured compost mixed with antagonists Paenibacillus polymyxa SQR-21 and Trichoderma harzianum T37 (BIO1), Bacillus amyloliquefaciens N6 (BIO2), Bacillus subtilis N11 (BIO3), and the combination of N6 and N11 (BIO4). The results indicated that the application of BIOs significantly decreased the incidence rate of Fusarium wilt by up to 80% compared with the control. BIOs also significantly promoted plant growth, and increased chitinase and β-1,3-glucanase activities by 55%–65% and 17.3%–120.1%, respectively, in the banana roots. The population of FOC in the rhizosphere soil was decreased significantly to about 104 colony forming units g−1 with treatment of BIOs. Serial dilution plating and denaturing gradient gel electrophoresis analysis revealed that the application of BIOs increased the densities of bacteria and actinomycetes but decreased the number of fungi in the rhizosphere soil. In general, the application of BIOs revealed a great potential for the control of Fusarium wilt disease of banana plants.