Hot-water treatments of potted palms to control the burrowing nematode, Radopholus similis

Abstract

Hot-water treatments were evaluated to disinfect roots and media of potted bamboo or Reed palm, Chamaedorea seifrizii Burret, and fishtail palm, Caryota mitis Lour. of the burrowing nematode, Radopholus similis (Cobb) Thorne. A continuous hot-water drenching (50°C for 15 min) of roots and media in pots or hot-water dipping (50°C for 15 min) of bare-rooted plants were successful in eliminating all burrowing nematodes in bamboo palms. Fishtail palms were disinfected of burrowing nematodes after hot-water drenching at 50°C for 13 min. Dipping plants intact in pots in a constant temperature water bath was not effective, as the root temperature remained below the thermal death point for nematodes due to slow heat transfer. No evidence of thermal damage was observed in either palm species drenched with hot water at 50°C for up to 20 min followed by hydro-cooling to ambient temperature. Ambient air-cooling after heat-treatment was detrimental as the residual heat caused both vegetative and root damage in the potted palms. These air-cooled palms suffered reduced growth and required a longer recovery period.