Fire blight update

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. Most apple cultivars at our AREC have bloom open, some like Idared, are approaching full bloom and many flowers are expected to open over the next several days. This prediction is for trees with first bloom open Monday, April 20, 2014. The temperature and rainfall data are current through this morning,  April 23. Predicted weather conditions are shown for April 24-May 2. 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 will be high for Apr 25, but the temperatures would need to be warmer over the next two days for infection to be predicted for Apr 25. For infection to be predicted, wetting must occur after the EIP (epiphytic infection potential) reaches 100 or higher. Following the higher risk on Apr 25, the current forecast with cooler predicted temperatures holds the risk at a low to moderate rating through May 2. 

This graphic will be updated April 25. 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.