Limited Effectiveness of Conventional Sanitisers and Hot Water as an Alternative for Preventing the Spread of <i>Ceratocystis fimbriata</i> via Tools

ABSTRACT Wounds are crucial entry points for infection by Ceratocystis spp. Consequently, tool disinfestation is a crucial practice in disease management, especially for host crops such as kiwifruit, teak, mango and cacao, which require cultural practices that cause wounds, such as pruning and thinning. Although conventional sanitisers, such as sodium hypochlorite, are recommended for controlling Ceratocystis wilt, their effectiveness on tools lacks scientific validation. Additionally, there is no consensus on the optimal exposure time and active ingredient concentration for effective disinfestation. Our study confirmed that C. fimbriata can be mechanically spread from diseased to healthy plants via pruning shears. We then evaluated the effectiveness of conventional sanitisers and hot water (80°C) for the disinfestation of pruning shears and scalpels on kiwifruit plants. Firstly, in vitro comparisons revealed that ammonium chloride solution and hot water effectively inhibited the mycelial growth of the fungus. Furthermore, immersing tools in hot water (80°C for 15 s) was the only effective disinfestation method, while sodium hypochlorite and other conventional sanitisers failed to eliminate the pathogen at the dosages and exposure times tested. Based on these findings, a revision of disinfestation protocols for Ceratocystis wilt is recommended, with further studies needed to evaluate different concentrations and exposure times. In conclusion, hot water is an effective alternative to conventional sanitisers in preventing the mechanical spread of the pathogen.