Biocontrol of Fusarium wilt disease for Cucumis melo melon using bio-organic fertilizer

Fusarium wilt disease in melon (Cucumis melo L) is widespread, responsible for serious economic losses. Pot and field experiments were performed to investigate the effects of different bio-organic fertilizers (BIOS) made from organic fertilizer and different antagonistic microbes. BIOs decreased the incidence of fusarium wilt disease and increased melon yield. The disease incidence of treatments with double application (BIOS applied both in the nursery and in the pot soil) was 20%, much lower than control (80%). Moreover, double application of a mix termed BIOII resulted in a 17.4-fold increase in plant fresh weight compared to control. Application of BIOs strongly reduced the number of pathogen colony-forming units (cfu) in stems and roots of melon. Pathogen populations were 2.27 x 10(3) and 6.67 x 10(3) cfu g(-1) FW (fresh weight) on BIOII-treated stems and roots, respectively, and 8.17 x 10(4) and 3.67 x 10(4) cfu g(-1) FW on control stems and roots, respectively; i.e., cfus were reduced by 97% and 82%, respectively. Microbial community structure was ameliorated by all BIOs. The number of bacteria and actinomycota in rhizosphere soil increased markedly under all BIO applications compared to control. In contrast, pathogen and fungal density was dramatically higher in the rhizosphere of control plants. The activities of defense enzymes in the leaves of melons receiving double application of BIOII were lower than those of control plants. The highest melon yield was achieved by plants that received a double application of BIOII in field experiments (7225 kg ha(-1) vs. 4447 kg ha(-1) for control plants). In conclusion, the most effective treatment was double application of BIOII, which minimized the incidence of wilt disease, maximized biomass production, and altered microbial community structure. (c) 2010 Elsevier B.V. All rights reserved.