Effects of different bio-organic fertilizers on fusarium wilt control and on the rhizosphere microbial community with muskmelon

Pot experiment were conducted to study the effect of different bio-organic fertilizers(BIO)on the control of fusarium wilt of muskmelon and rhizosphere microflora in a continuous cropping muskmelon soil by means of dilution plate counting and DGGE technology.The results showed that application of BIO could significantly increase muskmelon biomass and decrease incidence of the soil born disease.In the fruiting period,the plant fresh weight and dry weight under the mixed application of Bacillus subtilis Y-IV1(BIO1)with Trichoderma harzianum SQR-T37(BIO2)increased by 139% and 287% respectively,and the disease control rate was as high as 90.9%.The number of bacteria and actinomycota in rhizosphere soil siginificantly increased under all treatments of BIO applications compared to the control.In contrast,fungi and pathogen density was dramatically higher than those in the rhizosphere of the control treatment.The changes in microbes in the rhizosphere was the most notable under the mixed application of BIO1 with BIO2.Thus,application of hybrid BIOs significantly increased the disease control efficiency,promoted the growth of muskmelon,improved soil microflora in the rhizoplane and accelerated biological mediation in continuous cropping diseased soil.