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WJ Janisiewicz, F Takeda – US Patent 20,170,274,106, 2017

Abstract

Strawberries are available year-around from production in the field or from controlled environments (e.g. high and low tunnel culture and greenhouse). Diversity of production conditions results in challenges in controlling diseases before, during, and after harvest. Fungicides, traditionally used to control diseases, have limitations. UV-C irradiation followed by a dark period was used to kill two major pathogens of strawberry, Botrytis cinerea and Colletotrichum acutatum. The UV-C irradiation and dark period was followed by repopulation with beneficial biocontrol microorganisms. The 4 hr dark period prevented activation of a light-dependent UV-C damage repair mechanism in the pathogens. This combination protocol makes it possible to use a lower dose of UV-C for reduction and/or elimination of pathogens. A mobile treatment apparatus was designed to provide the appropriately timed UV-C doses, dark period, and sprayable doses of biocontrol microorganisms. The UV-C dose and repeated exposure did not affect pollen germination or cause chlorophyll degradation in strawberry leaves.

  The irradiation intensity at the distance of 30 cm was 0.206 W/m 2 (20.6 μW/cm 2 ). Thus, the 60 sec illumination corresponded to 12.36 J/m 2 (0.001236 J/cm 2 ). Irradiance was measure with a calibrated spectrometer (StellarNet, Inc. EPP2000, Tampa, Fla.).