CAUTION: The observations, conditions, and recommendations reported for Winchester, VA are provided as a guide to fire blight risk assessment only for the immediate area of the Virginia Tech AREC located six miles southwest of Winchester. Use of the information reported here for making orchard management decisions outside of that area is not our intent. Fruit producers outside of that area are encouraged to consult their state extension specialists for information similar to that provided here.
FIRE BLIGHT: Above is a cropped graphic from the Maryblyt 7 program. With early cultivars showing much bloom, and others expected to come into bloom with warm temperatures today, here is a prediction for trees with first bloom open Monday, April 5, 2010. The temperature and rainfall data are current through Wednesday morning, April 7. Predicted weather conditions are shown for April 7-11. The components of fire blight risk are indicated in the columns labeled B (blossoms open), H (degree hours for epiphytic bacterial populations), W (wetting by rain or dew), and T (average daily temperature 60 F or above). Based on predicted temperatures and wetting, The risk column shows that fire blight infection (I) is possible with predicted thunderstorms tomorrow, April 8 (note red color). For infection to be predicted, wetting has to occur after the EIP (epiphytic infection potential) reaches 100 or higher. Briefly put, any bloom that opens today is at risk for infection if wetting occurs tomorrow. The current longer-range outlook indicates cool temperatures April 9-10, followed by warmer again April 11-12. This graphic will be updated April 8. The BBS and CBS columns are tracking predicted blossom blight symptom and canker blight symptom appearance, respectively. The weather conditions used in the predictive part of this graphic come from the Weather Channel for Winchester, supplemented by site-specific data from Skybit, Inc.
