Effects of the consortium of endophytic bacteria, chitinolytic bacteria, and plant growth-promoting rhizobacteria on the growth of banana and the accumulation of banana bunchy top virus

Banana bunchy top is one of the most important diseases of banana in Indonesia Nurhayati (2003), in West Java (Bogor, Cianjur, Pandiglang,Subang dan Sumedang) the virus has been spread widely with the disease incidence was about 7.2-38.6%. As an alternative control of the disease, each isolate of endophytic bacteria (Pseudomonas PK5), chitinolytic bacteria (Aeromonas caveae), and plant growth-promoting rhizobacteria (Bacillus cereus L32) were investigated individually and/or in combination. The effects of treatments were also investigated to the abundance of fluorescent Pseudomonade and heat tolerance bacteria using plant-count method. Based on the green house experiment data, at 60 days after inoculation of banana bunchy top virus (BBTV) the height of the plant treated with bacteria were significantly higher than control plants. The height of the plants treated with bacteria was at range of 82.7 to 88.2 cm while control was up to 71.6 cm. The accumulation of BBTV on the plants treated with endophytic or chitinolytic bacteria individually were not significantly different compared with control but for the other treatment the accumulation of BBTV was higher than control. In the field, 120 days after transplanting, the diameters of stem of plants treated with Bacillus and/or A. caveae, individually or in combination among them, were relatively lower compared with control. Application of Pseudomonas individually or in combination with Bacillus or A. caveae caused the diameter of stem were relatively higher than control. The highest diameter of stem on 120 days after treatment was up to 17.27 cm on the plants treated with Pseudomonas combined with A. caveae. The highest population of heat tolerant bacteria, i.e. 1.8x10sup4 cfu/g soil, was found in the soil both treated with combination of Bacillus + A. caveae, i.e. 1x10sup3 cfu/g soil. Population of fluorescent Pseudomonas in the soil treated with Bacillus and Bacillus + Pseudomonas was similar with control, while in the other treatments the population of fluorescent Pseudomonas were relatively higher than those in control.