Fire Blight Warning 4/15/2024: Isolated Severe Thunderstorms Possible with Hail This Afternoon In Virginia, Could Cause Intensive Fire Blight Spreading and Trauma Blight

TO ALL LOCATIONS WITH POME FRUIT IN VIRGINIA: On top of the NEWA EIP model as of this morning reporting fire blight infections for all Virginia 15-18 April we also have a warning for isolated severe thunderstorm weather predicted for all Virginia locations from Bristol, Rustburg, Roseland, Tyro, Timberville, Winchester to Cross Junction that has a chance to bring small to large size hail and wind gusts that can trigger natural fire blight infections as per screenshots below. This can not only trigger flower infections but trauma blight, i.e. infections on green and woody tissues due to injury, plus severe fire blight spreading to other locations due to winds. Please apply streptomycin today, withing 24 h before a wetting event or up to 24h after the storm started, type in the date of streptomycin application into he NEWA EIP model and look how the model re-calibrates the reported infections.

Fire blight EIP values, as of today, are over 100 and Dark Red reporting Infections for all locations for the next 2-4 days in Virginia. This has changed due to the change in the forecast form yesterday. It changed as per my yesterday’s bog post from some locations having reported Infections to all locations in VA having reported infections: Fire Blight Infections Predicted in Several Locations 15 – 18 April: Check Your NEWA EIP Model for Closest Weather Station,

SPRAY OPTION TO USE: preventive streptomycin – cover before the predicted wetting event any apple and pear trees in bloom with streptomycin: Harbor, or Agrimycin 17 WP, or FireWall 17 WP at 1.5 to 3 lb per acre (24 – 48 oz/A) plus LI 700 at a penetrating rate or use Regulaid instead of LI700. Based on the Regulaid label, you could use 2 pints penetrating rate. FireWall changed its formulation to FireWall 50WP and the rate to use this higher concentrated material is 8 – 16 oz/A. If rain does not occur, you can trigger the infection at EIP 100 or above if you provide water with a fungicide spray application, so if you are applying a previously planned fungicide application – add streptomycin to it.

EMERGENCY SPRAY OPTION: Only if you miss somehow to cover certain blocks with streptomycin today due to large acreage, go in tomorrow, 16 April and apply streptomycin withing 24 h from the start of a rain today (the sooner after rain the better). Apply streptomycin in mix with Regulaid or LI700 up to 24 h after the infection rain event started (kick-back mode of application). In case you will use LI700 instead of Regulaid, use a penetrating action rate for LI700.

If you used captan recently, DO NOT add Regulaid or LI700 to streptomycin for this spray. Keep in mind that hail can damage not only fruit but bark on twigs, shoots, branches and trunk, opening wounds that can be infected with fire blight and lead to trauma blight. If you had a recent history of fire blight and storm does occur on your location, this spray is essential. Please examine hail warnings for Winchester, Timberville, Tyro, and Bristol VA (Source:, then please examine the NEWA EIP model outputs – the right colored column in the screenshots below the hail warnings (Source: