Farmer Friendly Options for Sterilizing Farm Tools for the Control of Xanthomonas Wilt Disease of Banana

Abstract

The adoption of tool sterilization using either 3.5% sodium hypochlorite (household bleach) or fire, a core element of the cultural control packages for Xanthomonas wilt (XW) of banana has been poorly adopted hampering XW control in East and Central Africa. Household bleach is costly and not accessible to the rural poor while repeated heating weakens metal blades of garden tools (machetes, knives, and hoes). Identification of economically viable tool sterilization options is thus crucial for XW management. We explored a range of practices including tool insertion for varying time periods into cold and hot ash, fire and boiling water; tool exposure over varying time periods to the sun while under black or transparent plastic sheets; and washing tools with cold water and laundry soap or detergent. Cleaning with household bleach served as a negative control while uncleaned tools as positive control. Like for household bleach, no Xanthomonas vasicola pv. musacearum (Xvm) the causal agent of XW was recovered from tools washed with cold water and different laundry soaps or detergents. Culturing Xvm in varying detergent and soap concentrations (0.00125–0.035 g/mL), only resulted in growth at lower concentrations of 0.00125 and 0.0025 g/mL. The cleaning effect of soap could thus be due to both an anti-bacterial effect and dislodgment of bacteria from tools. Laundry soaps/detergents are cheaper than household bleach and used for various purposes within and across households, including the resource poor and rural households, hence a cheaper and convenient tool sterilization alternative. Tool insertion into boiling water was effective from the 40th second and thus a viable alternative. Heating tools in fire required up to a minute to clear all bacteria. The currently recommended 20–40 s heating could thus be inadequate. Repeated heating for 1 min may also damage tools. Other practices (washing with cold water only, use of solar radiation, repeatedly and forcefully inserting tools into the soil, tool insertion into hot and cold ash for up to 5 min) only reduced Xvm populations on tools, thus not independently recommended. We recommend expanding the tool sterilization options to include washing with soap/ detergents and tool insertion into boiling water for at least 1 min.

Xanthomonas wilt of enset in Ethiopia: Geographical spread, impact on production systems and the effect of training on disease management practices

“…Firstly, while trained farmers were well aware of the need for hygienic practices, very few provided details on what this entailed, including washing or fire-treating of garden tools. The implementation of tool sterilization as a XW control practice has often been reported as impractical, as repetitive excessive heating of metal tool blades can damage the tools, and household bleach can be too expensive for regular use (Ochola et al, 2014;Blomme et al, 2019;Ocimati et al, 2021). The use of soapy water or boiling water could be more practical and affordable (Ocimati et al, 2021), increasing its adoption for longterm management.…”

“…The implementation of tool sterilization as a XW control practice has often been reported as impractical, as repetitive excessive heating of metal tool blades can damage the tools, and household bleach can be too expensive for regular use (Ochola et al, 2014;Blomme et al, 2019;Ocimati et al, 2021). The use of soapy water or boiling water could be more practical and affordable (Ocimati et al, 2021), increasing its adoption for longterm management. Importantly, the use of clean planting material was not reported by any of the households.…”

Scaling Banana Bacterial Wilt Management Through Single Diseased Stem Removal in the Great Lakes Region

“…Tool sterilization, a core component of SDSR and CMU, was infrequently used due to the expense and low availability of household bleach (3.5% sodium hypochlorite solution) in remote rural areas and because tools were damaged by repeated heating on fire (Blomme et al 2014(Blomme et al , 2019Kikulwe et al 2019). A later study showed that washing tools with cold water and soap or detergent (more readily available and cheaper) and immersing tools in boiling water for a minute are as effective as bleach (Ocimati et al 2021). Using soap or detergent and boiling water will increase the options for tool sterilization and encourage more farmers to sterilize their tools.…”

“…This led to the exploration of cheaper, readily accessible, and easy-to-use alternatives. Washing metals in cold water with laundry soap or detergent or immersing tools in boiling water for a minute were found to be as effective as household bleach (Ocimati et al 2021). Soap and detergents are readily available in shops even in remote communities.…”

“…Washing tools to sterilize them is easy to use even where other techniques are not applicable, e.g., it may be hard to light a fire on rainy days or fire be a hazard, especially where farms are far from the homestead. Washing tools for a minute in soap and water was long enough to sterilize them (Ocimati et al 2021). Repeated heating in fire will certainly weaken steel tools, and farmers are loathe to buying new ones any more frequently than is necessary.…”