Chemical and cultural control of bacterial blossom blight of kiwifruit caused by Pseudomonas syringae in Korea

Abstract

Disease incidence of bacterial blossom blight (Pseudomonas syringae van Hall) ranged from 13.0 to 36.2% in naturally infected kiwifruit (Actinidia deliciosa (A. Chev) C. F. Liang et A. R. Ferguson) orchards of the major kiwi fruit‐growing areas in Korea from 1997 to 1999. A significant correlation occurred between disease incidence and rainfall at flowering. Several control practices were compared with conventional chemical control to prevent bacterial blossom blight of kiwifruit. Streptomycin sulfate + oxytetracycline WP applied 3 times at 10‐day intervals resulted in control efficiencies from 75.6 to 79.8% in 1997 and 1998, respectively. Trunk injection of various concentrations of acetic acid also displayed variable control efficiencies. Injection with 7% (v/v) acetic acid was the best injection treatment with control efficiencies from 70.9 to 77.0%. Use of a transparent polyvinyl film to protect kiwifruit trees from rain or girdling of trunks of kiwifruit trees alleviated the diseases at rates of 61.0–84.7 or 65.7–76.8%, respectively. The results suggest that trunk injection of acetic acids, girdling on trunks, and rainproof installation over kiwifruit trees can be applied as reasonable control practices to manage bacterial blossom blight in kiwifruit orchards in Korea.