2021 Volume 20 Issue 2 Pages 225-231
The disease-controlling effect of Farm-A, a special liquid fertilizer composed of fermented hot water extract of sweetleaf (Stevia rebaudiana), was investigated. At 0.1 to 1% concentration, its effect against strawberry gray mold (Botrytis cinerea) and anthracnose (Colletotrichum gloeosporioides) was similar to that of dodecylbenzenesulphonic acid bisethylenediamine copper [II] salt (DBEDC) and propineb. The residual effect was prolonged compared with that of DBEDC. However, although DBEDC showed antibacterial activity against gray mold in culture medium, this activity was not observed with the fermented hot water extract of sweetleaf. As a result of treating whole cucumber seedlings in the two-leaf stage with the fermented hot water extract of sweetleaf, gray mold was controlled. Furthermore, even when the treatment was applied only to the first leaf, gray mold was controlled in the latter leaves that were not treated, and the expression level of the peroxidase gene increased in the first leaf. As a control effect was observed for multiple diseases, the residual effect was prolonged, a disease-controlling effect was observed even with local treatment, and it led to increased expression of related genes, it was considered that this effect of fermented hot water extract of sweetleaf on diseases is likely due to systemic acquired resistance.