Evaluating UV-C Sensitivity of Calonectria pseudonaviculata in Model Buffer Solution Using a UV-C...

Area of Science:

• Plant Pathology
• Microbial Disinfection
• Horticultural Science

Background:

• Boxwood blight, caused by *Calonectria pseudonaviculata*, is a major threat to boxwood production.
• The pathogen produces sticky conidia that contaminate tools and equipment, facilitating disease spread.

Purpose of the Study:

• To evaluate UV-C light-emitting-diode (LED) irradiation as a disinfection method for *Calonectria pseudonaviculata* conidia.
• To determine the UV-C sensitivity and inactivation kinetics of the pathogen's conidia.

Main Methods:

• Conidial suspensions were exposed to quantifiable UV-C doses (263 to 287 nm) under dynamic stirring.
• UV dose was calculated using average fluence rate and exposure time, accounting for UV gradients.
• Inactivation followed log-linear + shoulder kinetics, with model fit assessed by R² and RMSE.

Main Results:

• UV-C irradiation effectively inactivated *C. pseudonaviculata* conidia.
• The predicted UV sensitivity was 46.6 mJ·cm⁻² per log reduction.
• A UV-C dose of 60 mJ·cm⁻² achieved a 2.04 log reduction.
• The decimal reduction dose (D₁₀) was 13.53 ± 0.98 mJ·cm⁻².

Conclusions:

• UV-C irradiation is a viable method for disinfecting tools, equipment, and potentially propagation cuttings in nurseries.
• This technology can help manage boxwood blight by reducing pathogen contamination.
• Further application in nursery sanitation protocols is recommended.