Submitted to: Goodfruit Grower
Publication Type: Popular Publication
Publication Acceptance Date: January 16, 2004
Publication Date: March 1, 2004
Citation: Pusey, P.L. Soil water relates to fire blight risk. 2004. Good Fruit Grower. 55:11-12. Technical Abstract: It is well established that atmospheric water plays an important role in the development of fire blight initiated in blossoms of apple and pear. Prior to a recently published study, however, it was unknown whether water inside blossoms relates to infection. The answer to this question has practical relevance in dry production areas requiring irrigation. A water potential range was established by varying relative humidity around detached flowers, or the concentration of sugar solute in vials supporting cut stems. Water potential was based on analysis of ovary tissue sections using a vapor pressure osmometer. Disease incidence and severity was positively correlated with water potential at a high level of statistical significance. Unless trees desperately need water during the bloom period, which is seldom the case, growers are advised to delay irrigation, particularly at sites with a history of fire blight.