Biocontrol of Large Patch Disease in Zoysiagrass (Zoysia japonica) by Bacillus subtilis SA-15: Identification of Active Compounds and Synergism with a Fungicide

Geung-Joo Lee,Hong-Gi Kim,Kyo-Suk Lee,Young-Sun Kim

doi:10.3390/horticulturae8010034

Geung-Joo Lee, Hong-Gi Kim + Show 2 more

Open Access

https://doi.org/10.3390/horticulturae8010034

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Journal: Horticulturae	Publication Date: Dec 29, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: Chungnam National University, Daegu University

Abstract

Bacillus subtilis SA-15 is a plant growth-promoting bacterium isolated from non-farming soil. We aimed to identify lipopeptides produced by B. subtilis SA-15 and evaluate the control efficacy of B. subtilis SA-15 against large patch disease caused by Rhizoctonia solani AG 2-2 (IV) in zoysiagrass (Zoysia japonica). Bacillus subtilis SA-15 inhibited mycelial growth of R. solani AG 2-2 (IV) in vitro and produced fengycin A and dehydroxyfengycin A, which are antifungal compounds. Fengycin A and deghydroxyfengycin A inhibited R. solani mycelial growth by 30.4 and 63.2%, respectively. We formulated B. subtilis SA-15 into a wettable powder and determined its control efficiency against large patch in a field trial. The control efficacy was 51.2–92.0%. Moreover, when B. subtilis SA-15 powder was applied together with half the regular dose of the fungicide pecycuron, the control efficacy was 88.5–100.0%. These results indicate that B. subtilis SA-15 can be used to control soil-borne diseases, including large patch caused by R. solani, because of lipopeptide production. The use of this bacterium can also reduce the amount of fungicide needed, providing an eco-friendly management option for turfgrass.

Highlights

Large patch caused by Rhizoctonia solani AG 2-2 (IV) is a well-known disease of zoysiagrass (Zoysia japonica), which is planted in 70% of golf course fairways in Korea [1,2]
Large patch in zoysiagrass is caused by R. solani AG 2-2 (IV) in theTreatment thatch layer in the fairways of golf courses [4]
We found that the SA-15 strain inhibited R. solani AG 2-2 (IV) in vitro and suppressed large patch disease in vivo

Summary

Introduction

Large patch caused by Rhizoctonia solani AG 2-2 (IV) is a well-known disease of zoysiagrass (Zoysia japonica), which is planted in 70% of golf course fairways in Korea [1,2]. Large patch on zoysiagrass is controlled by applying fungicides, such as pencycuron, or by decreasing organic matter in the root zone via soil renovations in golf courses. Various management practices can be used to reduce the amount of organic matter in the thatch layer, including topdressing, aeration, and vertical mowing [3]. These management practices help to increase microbial activity

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