# Essential Oil of Xylopia frutescens Controls Rice Sheath Blight Without Harming the Beneficial Biocontrol Agent Trichoderma asperellum

## TL;DR

Xylopia frutescens essential oil effectively controls rice sheath blight without harming the beneficial fungus Trichoderma asperellum.

## Contribution

The study identifies Xylopia frutescens essential oil as a selective, sustainable fungicide for rice sheath blight.

## Key findings

- Trans-pinocarveol and myrtenal in Xylopia frutescens essential oil interact with R. solani lectin, showing antifungal activity.
- The essential oil inhibited R. solani growth in vitro and reduced disease severity in rice with low phytotoxicity.
- Trichoderma asperellum remained unaffected by the essential oil, indicating its selectivity and safety.

## Abstract

Rice production experiences significant losses due to fungal diseases, particularly rice sheath blight caused by Rhizoctonia solani. Despite the intensive and continuous use of synthetic fungicides, diseases severity has not reduced and control has become increasingly challenging; therefore, the search for environmentally friendly and sustainable products has intensified. Here, we conducted a chemical characterization of Xylopia frutescens and using in silico analysis evaluated the interaction of their two major compounds with lectin protein site of R. solani. In vitro tests using increasing concentrations of essential oil against R. solani were performed. Subsequently, in four varieties of rice, five concentrations of X. frutescens essential oils were applied and evaluated the phytotoxicity effect as well the potential of Xylopia frutescens essential oil for controlling, both preventively and curatively, rice sheath blight. We further investigate the selectivity of this essential oil towards the non-target organism, Trichoderma asperellum. Our analysis revealed that trans-pinocarveol and myrtenal are the main compounds of X. frutescens essential oil and interact with the lectin of R. solani, supporting the antifungal properties of X. frutescens essential oil. In in vitro conditions, the highest tested concentrations of X. frutescens essential oil inhibited the pathogen’s sclerotia and mycelial growth. Under greenhouse conditions, the treatments caused low phytotoxicity and effectively reduced disease severity when applied, both preventively and curatively. Furthermore, the biocontrol agent T. asperellum exhibited tolerance to X. frutescens essential oil. Collectively, our findings demonstrate the potential of X. frutescens essential oil for the development of botanical fungicides capable of controlling R. solani without harming beneficial non-target organisms such as T. asperellum.