Influence of Water Stress on Susceptibility of Nonwounded Peach Bark to Botryosphaeria dothidea

From May to September inoculated trees were irrigated daily or had water withheld for 2,4, or 6 days in each 8-day cycle. At the end of the lest, trees with the 6-day withholding had higher mean values for number of gum exudation sites and number of lesions and a higher percentage of bark necrosis than trees in the other treatment groups (P=0.05). In 1986, the effect of severe water stress at or near the time of inoculation was determined by stopping daily irrigation of trees 2 days before inoculation and starting irrigation again after leaf water potential had dropped to below-3.0 MPa