Modification of Fungicide Treatment Needs and Antioxidant Content as a Result of Real-Time Ozonation of Raspberry Plants

Raspberry plants need intensive anti-fungal protection. A solution to this problem could be the application of an ozonation process. For this purpose, a technical solution was proposed and implemented in raspberry plant production. The proposal suggests replacing 25% of standard fungicide treatments with ozonation. It was demonstrated that the use of ozone under the proposed conditions made it possible to maintain stable parameters of chlorophyll content and fluorescence (no significant differences), but the intensity of gas exchange was increased. The greatest differences were observed in the second measurement period (T2), when the plants were in the stage of most active development. Additionally, the content and profile of low-molecular-weight antioxidants and the microbial load were determined in the collected fruits. In periods T2 and T3, the proposed method caused a reduction reaching ~2 log cfu g^-1 in the microbial content of raspberry fruits. It was shown that ozone treatment intensified the biosynthesis of low-molecular-weight antioxidants in fruit (increasing the total polyphenol content by more than 20%). The proposed scheme allows a 25% reduction in standard fungicide treatments while maintaining the health of cultivated raspberry plants. The reduction in fungicide use aligns with the EU regulations and produces fruit with better quality.