Tool Sterilization to Prevent Viroid Transmission

A Comprehensive Literature Review

Tool Sterilization Recommendation

To prevent mechanical transmission of viroids in cannabis facilities, a dilute bleach solution should be used to disinfect tools, surfaces and gloved hands between plants.

To create a 10% dilute bleach solution mix:

1 part household bleach (>5% active ingredient -sodium hypochlorite)
9 parts water

To create a 20% dilute bleach solution mix:

1 part household bleach (>5% active ingredient -sodium hypochlorite)
4 parts water

Potentially contaminated tools should remain in the bleach solution for 60 seconds or more to allow complete deactivation. Bleach is corrosive to metal tools so prolonged incubation is not recommended. The bleach solution should be mixed fresh at the start of each day and replaced if the solution becomes saturated with plant material. Dilute bleach in a spray bottle can be used periodically to disinfect gloved hands.

Literature Summary Data

The tables below summarize results from published scientific reports investigating the efficacy of various chemicals and treatments for removal of viroid contamination from tools. Only studies where effectiveness was determined by inoculation of clean plants with sterilized tools are included in this summary. Tables indicate the concentration(s) of each chemical used in the studies, details of the treatment applied and the percent transmissibility that remained after disinfection.

Tool Sterilization Tables

References

Desjardins, P.R., Saski, P.J., Drake, R.J., 1987. Chemical inactivation of avocado sunblotch viroid on pruning and propagation tools. Calif. Avocado Soc. 1987 Yearbook. 71,259 262.
Garnsey, S.M., Whidden, R., 1971. Decontamination treatments to reduce the spread of citrus exocortis virus (CEV) by contaminated tools. Proc. Fla. State Hort. Soc. 84,63 67.
Hollings, M., Stone, O.M., 1973. Some properties of chrysanthemum stunt, a virus with the characterization of an uncoated ribonucleic acid. Ann. Appl. Biol. 74, 333 348.
Li, R., Baysal-Gurel, F., Abdo, Z., Miller, S.A., Ling, K.S., 2015. Evaluation of disinfectants to prevent mechanical transmission of viruses and a viroid in greenhouse tomato production.Virology J. 12, 5.
Mackie, A.E., Coutts, B.A., Barbetti, M.J., Rodoni, B.C., McKirdy, S.J., Jones, R.A.C., 2015. Potato spindle tuber viroid: stability on common surfaces and inactivation with disinfectants. Plant Dis. 99, 770 775.
Matsuura, S., Matsushita, Y., Usugi, T., Tsuda, S., 2010. Disinfection of tomato chlorotic dwarf viroid by chemical and biological agents. Crop Prot. 29, 1157 1161.
Roistacher, C.N., Calavan, E.C., Blue, R.L., 1969. Citrus exocortis virus – chemical inactivation on tools, tolerance to heat and separation of isolates. Plant Dis. Reptr. 53,333 336.
Singh, R.P., Boucher, A., Somerville, T.H., 1989. Evaluation of chemicals for disinfection of laboratory equipment exposed to potato spindle tuber viroid. Am. Potato J. 66,239 245.
Thi Thu, 2018. Studies on transmissibility, cytopathology and control of Tomato chlorotic dwarf viroid and Potato spindle tuber viroid. Doctoral Thesis, Bonn University
Timmermann, C., Mu¨ hlbach, H.P., Bandte, M., Bu¨ ttner, C., 2001. Control of mechanical viroid transmission by the disinfection of tables and tools. Meded Rijksuniv Gent Fak Landbouwkd Toegep Biol. Wet. 66, 151 156.