Potential use of ash and lye to sterilize farm tools contaminated with Xanthomonas vasicola pv. musacearum

Tool sterilization is a critical component of managing Xanthomonas wilt of banana, because it disrupts a key transmission pathway of the causal agent Xanthomonas vasicola pv. musacearum ( Xvm ). Despite the availability of several sterilization options, uptake by smallholder farmers remains limited due to high costs, low accessibility, and practical constraints under field conditions. To broaden feasible and low-cost options, we evaluated locally sourced wood ash and homemade lye solutions (ash mixed with water) as alternative decontaminants for farm tools. Methods In the laboratory, iron or steel made knife blades coated with Xvm from freshly cut banana stems were inserted into i) dry ash, ii) un-boiled lye and iii) boiled lye for 2, 8, 16, 24, 48 and 72 h. In addition, blades were scrubbed with iv) un-boiled or v) boiled lye that had been allowed to settle for the same time durations. Tools scrubbed with household bleach and Xvm -coated tools left in shade served as controls. Each treatment was replicated nine times across three independent experiments. Results No Xvm colonies were recovered from blades scrubbed with household bleach whereas high colony counts were consistently recovered from untreated controls. Complete elimination of Xvm was achieved after immersion in boiled or un-boiled lye for at least 24 h, compared with 48 h when using dry ash. Scrubbing contaminated blades with lye that had settled for ≥24 h resulted in total removal of Xvm and was comparable in efficacy to household bleach. Boiling the lye did not enhance its disinfectant activity. Discussion These findings demonstrate that wood ash and lye provide practical, inexpensive alternatives for tool decontamination and can complement existing disease-management strategies, improving the feasibility of Xanthomonas wilt control for smallholder banana farmers.