Biological control of Pythium damping-off of cucumber by Bacillus stearothermophilus YC4194

Yang, Hyun Sook; Sohn, Hwang Bae; Chung, Young Ryun

Research in Plant Disease 2002;8(4):234-238.
Published online December 30, 2002.

Bacillus stearothermophilus YC4194에 의한 Pythium 모잘록병의 생물학적 방제

양현숙, 손황배, 정영륜

Biological control of Pythium damping-off of cucumber by Bacillus stearothermophilus YC4194

Hyun Sook Yang, Hwang Bae Sohn, Young Ryun Chung

Abstract

In vitro and in vivo activities of a biocontrol agent, Bacillus stearothermophilus strain YC4194 was evaluated for the control of Pythium damping-off of cucumber. B. stearothermophilus YC4194 inhibited germination of cystospores and formation of zoosporangia of Pythium aphanidermatum in vitro. Incorporation of a bentonite and talc based formulation(10(9) cfu/g) of B. stearothermophilus YC4194 to the nursery soils (10 g/l soil) resulted in a significant (p=0.01) reduction in the disease severity of cucumber damping-off after inoculation with P. aphanidermatum. The control efficacy of B. stearothermophilus YC4194 formulation was not different from that of the fungicides, dimethomorph, metalaxyl, ethaboxam. When the cucumber plants were transplanted to the soil inoculated with P. aphanidermatum zoospores, the B. stearothermophilus YC4194 maintained the high population density in rhizosphere soil upto 10(7) cfu/g until 15 days after treatment.

Key Words: Pythium, Biological control, Inhibition of zoosporangia and cystospores germination