Botrytiscinerea is a severe threat in agriculture, as it can infect over 200 different crop species with gray mold affecting food yields and quality. The conventional treatment using fungicides lead to emerging resistance over the past decades. Here, we introduce Photodynamic Inactivation (PDI) as a strategy to combat B.cinerea infections, independent of fungicide resistance. PDI uses photoactive compounds, which upon illumination create reactive oxygen species toxic forkilling target organisms. This study focuses on different formulations of sodium-magnesium-chlorophyllin (Chl, food additive E140) as photoactive compound in combination with EDTA disodium salt dihydrate (Na2EDTA) as cell-wall permeabilizer and a surfactant. In an in vitro experiment, three different photosensitizers (PS)with varying Chl and Na2EDTA concentrations were tested against five B.cinerea strains with different resistance mechanisms. We showed that all B.cinerea mycelial spheres of all tested strains were eradicated with concentrations as low as 224µM Chl and 3.076mM Na2EDTA (LED illumination with main wavelength of 395nm, radiant exposure 106Jcm-2). To further test PDI as a Botrytis treatment strategy in agriculture a greenhouse trial was performed on B.cinerea infected bell pepper plants (CapsicumannumL). Two different rates (560 or 1120gHa-1) of PS formulation (0.204M Chl and 1.279M Na2EDTA) and a combination of PS formulation with 0.05% of the surfactant BRIJL4 (560gHa-1) were applied weekly for 4 weeks by spray application. Foliar lesions, percentage of leaves affected, percentage of leaf area diseased and AUDPC were significantly reduced, while percentage of marketable plants were increased by all treatments compared to a watertreated control, however, did not statistically differ from each other. No phytotoxicity was observed in any treatment. These results add to the proposition of employing PDI with the naturally sourced PS Chl in agricultural settings aimed at controlling B.cinerea disease. This approach seems to be effective regardless of the evolving resistance mechanisms observed in response to conventional antifungal treatments.