Spreading Dynamics of Mycoherbicide Sclerotium rolfsii in Controlling Herbicide‐Resistant Monocho

ABSTRACT

Sclerotium rolfsii is a soil‐borne fungal pathogen with potential as a mycoherbicide. Considering its spreading capability through mycelium, this study aimed to investigate the spatiotemporal spread of S. rolfsii on herbicide‐resistant (HR) Monochoria vaginalis , a problematic weed in paddy fields. In a controlled environment, S. rolfsii exhibited a circular spreading pattern, which was well described by the Gompertz model. At 1 day after treatment (DAT), germination initiated, followed by mycelium formation at 3 DAT. The infection expanded in a circular pattern at a rate of 118.72 cm ² /day, with the infection radius increasing by 1.59 cm/day. It was estimated that 10.9 days were required to control a 200 cm ² area and 13.3 days for a 600 cm ² area. Additionally, the complete infection of HR M. vaginalis occurred at approximately 2.2 days after mycelial contact, indicating the time for herbicidal action after mycelium expansion. Sclerotium rolfsii demonstrated a high mycelial spreading capacity and a prolonged persistence, highlighting its potential as an effective mycoherbicide. These findings also offer valuable insights for determining optimal application methods of S. rolfsii to control HR M. vaginalis . Further research will focus on how its spread and herbicidal efficacy vary under paddy field conditions.