Effectiveness of several plant extracts as botanical fungicides to control damping-off disease caused by Sclerotium rolfsii on soybean

Sclerotium rolfsii is the causal organism of the damping-off disease of soybean. Control of this disease is usually carried out by using chemical fungicides that have a negative impact on the environment. One of the efforts to overcome this problem is by using botanical fungicides from plant extracts. This study aims to determine the effect of plant extracts from Alpinia purpurata, Zingiber officinale, Curcuma longa, Curcuma xanthorrhiza, and Kaempferi galanga on the in-vitro growth of Sclerotium rolfsii and on the in-vivo of damping-off disease of soybean. In addition, a phytochemical test was also undertaken to determine the content of secondary compounds found in plant extracts. The experiment was carried out at the Chemistry Laboratory of the Faculty of Mathematics and Natural Sciences, Microbiology Laboratory and a Greenhouse of Faculty of Agriculture at the University of Mataram, from July until October 2020. The experiments used a completely randomized design (CRD) with seven treatments and three replications. The seven treatments were A. purpurata, Z. officinale, C. longa, C. xanthorrhiza, and K. galanga with a concentration of 5% (v/v), control (+), and the alcohol (-). The results showed that the extracts of A. purpurata, Z. officinale, C. longa, C. xanthorrhiza, and K. galanga with a concentration of 5% could suppress the growth of S.rolfsii by in-vitro. However, in the in-vivo trial, no extracts could suppress damping-off disease of soybean.