Design, Construction, and Evaluation of Equipment for Nighttime Applications of UV-C for Management of Strawberry Powdery Mildew in Florida and California
Paulo P. Mello, Rodrigo Onofre, Mark S. Rea, Andrew Bierman, David M. Gadoury, Kelly Ivors, Miranda Ganci, Jenny C. Broome, Natália A. Peres
Abstract
We designed and constructed two tractor-drawn ultraviolet-C (UV-C) lamp arrays housed in hemicylindrical hulls adapted to two widths of raised bed planting systems for strawberry. Onboard UV dosimeters were fitted to the arrays to monitor UV-C output in field studies to suppress strawberry powdery mildew. Nighttime applications of UV-C were evaluated in replicated-plot field plantings in Florida and in California. Suppression of powdery mildew by nighttime applications of UV-C at 200 J m −2 was equivalent to that provided by weekly fungicide applications in California and superior to that provided by fungicide treatments in Florida. Costs of construction and operation of the UV-C apparatus were estimated to allow comparisons to conventional fungicide-based suppression of disease. UV-C applications had no negative effects on yield nor any visual phytotoxic effect on plants or fruit throughout the season. The results confirm and expand upon previously published studies involving UV-C applications in different environments.