Effect of ultraviolet B radiation on pathogenic molds of grapes
The fungicidal effect of UV-C radiation (100-280 nm wavelength) is well known, but its applicability for the control of pathogenic molds of grapes is conditioned by its effect on the host and by the risks inherent in its handling
As an alternative, the effect in vitro of UV-B radiation (280-315 nm) on the main pathogenic molds of grapes has been studied: Botrytis cinerea, Aspergillus niger, Penicillium expansum and Rhizopus stolonifer.
The molds studied were seeded on Czapek agar plates (in triplicate) that were irradiated with UV-B radiation lamps located at a height of 25 cm, obtaining an irradiance of 16 Wm-2. Different exposure times (0, 1, 3, 6, 12 and 24 hours) were applied on two series of plates. One of the series was protected from radiation by UV radiation filters and acted as a control. After exposure, the plates were incubated at 20ºC in the darkness, assessing the degree of mold development over two weeks.
UV-B radiation caused a clear inhibitory effect on the development of the molds studied that was proportional to the irradiation dose received. The observed effect was different for each mold, being Rhizopus stolonipher and Botrytis cinerea the most sensitive to UV-B radiation. The resistance of molds to UV-B radiation has been related by different authors with mold pigmentation.
These results allow us to contemplate the use of UV-B radiation in the control of pathogenic molds of grapes.
1) Usall J. et al. (2016) Physical treatments to control postharvest diseases of fresh fruits and vegetables. Post. Biol. Tech., 122: 30-40, DOI 10.1016/j.postharvbio.2016.05.002
2) García-Cela, M.E. et al. (2016) Conidia survival of Aspergillus section Nigri, Flavi and Circumdati under UV-A and UV-B radiation with cycling temperature/light regime. J. Sci. Food Agric., 96:2249-2256, DOI 10.1002/jsfa.734
Issue: ICGWS 2023
Faculty of Science and Technology, University of La Rioja. 26006 Logroño (La Rioja), Spain
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UVR-B, pathogens molds, grapes