Keywords: 
• biocontrol bacteria /
• fusarium wilt /
• organic substrate /
• biological fertilizer

Abstract: To develop biological organic fertilizer for preventing and controling Fusarium wilt of banana, a bio-control bacterial strain LCQ1801 was isolated from the soil of rubber plantation in Chengmai, Hainan and its inhibition activity against Fusarium oxysporum f. sp. cubense race 4（Foc4）, the causal agent of banana Fusarium wilt was determined by using plate dual culture. The results indicated that LCQ1801 had obviously antagonistic effect on Foc4,and the inhibition rate was 65.9%. The LCQ1801 was identified as Bacillus velezensis by morphological observation,physiological and biochemical tests, combined with 16S rDNA sequencing analysis. Foc4 was cocultured with LCQ1801 bacterial liquid and filtrate, respectively. The result found that LCQ1801 bacterial fluid and filtrate caused abnormal growth or rupture of Foc4 hyphae and affected spore germination. At the same time, LCQ1801 was cultured on different substrates by using plate assay and culture flask culture. The plate assay indicated that the growth of LCQ1801 in the animal substrates of sheep dung, pig dung and cow dung was better than that in chicken dung. The growth of LCQ1801 in the plant substrates of wheat bran, corn flour, soybean meal and rice straw was better than that in the plant substrates of bagasse and coconut coir. Culture flask culture test showed that the number of viable bacteria of LCQ1801 in cow dung and sheep dung reached 16.8 billions·g^-1 and 24.0 billions·g^-1, respectively. The number of viable bacteria of LCQ1801 in rice straw, soybean meal and corn flour reached 32.2 billions·g^-1, 24.9 billions·g^-1 and 21.7 billions·g^-1, respectively. LCQ1801 hardly grew in the substrate of coconut coir in both culture styles. This study provides strain materials and technical support for biological control of Fusarium wilt of banana.