Degree Days are 'Actual' - based on individual temperature readings throughout the day. Plant Development Dates: Green Tip 04/15/2005 First Blossom 05/09/2005 University of Maryland Model: Apple threshold (80 DD>40) used for Blossom blight 'Steps' key: G Green Tip; from green tip date until Canker blight symptoms B Blossom; from first blossom date until Blossom blight symptoms (or Last Petal falls) H 198 Degree Hours > 65 requirement met W Wetness (dew or rain) requirement met T Average temperature >= 60 X Trauma; from trauma event date Washington State University (Cougarblight) Model: Pathogen Potential column header key: a No fire blight in area in past two seasons b Fire blight in local area in past two seasons c Fire blight in local area last year d Fire blight in orchard last year e Active cankers present nearby Infection Risk key: 0 Very low 1 Low 2 Low-Moderate 3 Moderate 4 High