Effect of the Microalga Chlorella fusca CHK0059 on Strawberry PGPR and Biological Control of Fusarium Wilt Disease in Non-Pesticide Hydroponic Strawberry Cultivation

The purpose of this study was to identify strawberry wilt pathogen and evaluate the efficacy of CHK0059 for improving plant growth and suppressing Fusarium wilt. We identified 10 isolates of wilt pathogens of non-pesticide Seolhyang strawberry plant, including f. sp. using morphological and molecular analysis. On the 15 day after 0.4% CHK0059 treatment, the plant height of the untreated control strawberry plants was significantly greater than that of the CHK0059 treated strawberry plants. On 85 days after treatment, both treatments showed a similar tendency with regard to the plant height of the strawberry plants. However, the thickness of strawberry leaves treated with the CHK0059 was found to be 1 mm thicker than that of the untreated control. The flowering percentage of the CHK0059 plants was also 40.2% higher on average than that of the untreated control. The chlorophyll content of strawberry leaves treated with the CHK0059 was also, on average 6.63 % higher than that of the untreated control. After 90 days of the CHK0059 treatment, the incidence of Fusarium wilt of the CHK0059 treated plants had reduced by 9.8% on average compared to the untreated control. The population density of f. sp. in the CHK0059 treatment reduced approximately 86.8% more than that of the untreated control at 70 days after treatment. The results indicate that the microalga, , CHK0059 is an efficient biological agent for improving strawberry plant growth and suppressing Fusarium wilt with disease in organic strawberries.