Warning 6/16/2023, 9 AM: Possible Hail in Virginia Could Cause Intensive Fire Blight Spreading and Trauma Blight Infections – Prepare to Apply Streptomycin Tomorrow if Hail Damage Occurs
TO ALL LOCATIONS WITH POME FRUIT IN VIRGINIA: Current storm weather affecting locations from Rustburg over Roseland, Timberville to Winchester has a high chance to bring small to large size hail and wind gusts that can contribute to trauma blight and severe fire blight spreading to other locations. If in your or in neighboring orchard you are seeing symptoms of fire blight be ready to apply streptomycin up to 24h after the storm started and if you had hail affect your orchard. Fire blight inoculum is readily available on many locations in Virginia – either as random blight strikes, cankers on wood, rootstock blight, or a more spread out but uniform infections on strikes. Since it is possible hail occurrence will vary highly from location to location wait to see if hail or wind gusts actually affect your location and then decide on applying this spray application. Even if you do not get hail and winds are violent, there is a chance fire blight can reach your orchard from a relatively distant location. If you used captan recently, DO NOT add Regulaid to streptomycin for this emergency 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 history of fire blight and storm does occur on your location, this spray is essential. For other locations that had no fire blight history, bear in mind that strong wind mph gusts can carry fire blight inoculum from relatively distant locations to (your) location that had no fire blight in the past. Shoots are still intensively growing on many apple cultivars and are prone to shoot tip infection. Hence, if strong storm described below happens and catches your orchard, make sure you spray streptomycin as soon as rain stops. This is the only time during summer and after bloom when streptomycin application is warranted. Aside from hail events, use of streptomycin at any time during summer, especially if you see fire blight symptom is strongly discouraged as it will lead to streptomycin resistance in Erwinia amylovora bacterium populations, making it ineffective. The complete hail warning is pasted below and screen shot is inserted. This goes without saying that your cover sprays will need to be re-applied on a tighter schedule than usual 14-21 days if we do reach 2 inches of rain during the storms ahead. You do not want to end up with summer rot issues in your orchard if you have done a good job protecting the crop so far.