Abstract
SUMMARY: Evidence from field observations and orchard plans indicates that the fireblight epidemic among apples in 1969 followed a critical combination of weather conditions. There is little doubt that diseased hawthorns, situated entirely or mainly to the north‐west of the main lanes of infection, were the source of inoculum. Initial infection was confined to shoots. No blossom infection was seen at any time. Weather data from a nearby meteorological station point to distribution of inoculum having taken place on one of the days 6–10 July when strong winds, rainfall and hailstorms occurred. These days were followed immediately by temperatures above 18d̀C which are considered suitable for infection and for progress of the bacterium within the shoot tissues. The control measures advised were the removal and destruction of diseased parts, the disinfection of pruning implements, the protection of wounded surfaces against infection and the destruction of nearby diseased hawthorns.

This publication has 1 reference indexed in Scilit: