Duration of susceptibility of apricot pruning wounds to infection by Eutypa armeniacae

The duration of susceptibility to infection by Eutypa armeniacae has been studied in field experiments involving inoculation of pruning wounds on apricot trees within and outside a rainproof shelter, thereby enabling susceptibility to be assessed in the absence of natural infection. The susceptibility of wounds made in early winter on sheltered trees declined from 100% on the day of pruning to c. 30% 4 weeks later. On unsheltered trees exposed to natural infection, inoculation of 2-week-old wounds did not increase the proportion infected above that occurring in non-inoculated wounds. An hypothesis is advanced to explain the decline in susceptibility with age of wound.