Assessment of Grapefruit Seed Extract Residues from Plum Tree Canker Surgery for Potential Topical Application

Bacterial canker of Japanese apricot (Prunus mume), caused by Pseudomonas amygdali pv. morsprunorum, leads to severe yield and quality loss. From 2023-2024, symptomatic tissues from Suncheon orchards were examined and the pathogen was confirmed by 16S rRNA sequencing. Surgical removal of diseased tissues using alcohol/flame-sterilized chisels, followed by wound protection with a 1:1 mixture of grapefruit seed extract and non-toxic silicone, effectively prevented decay, gummosis, premature defoliation, and fruit loss. In vitro assays showed strong antibacterial activity of grapefruit seed extract and its silicone mixture. These results demonstrate that a grapefruit seed extract-silicone dressing provides a simple, eco-friendly, and practical strategy for sustainable management of bacterial canker in P. mume.