Trauma blight

By Terence Bradshaw

May 19, 2017

An short, extremely intense line of thunderstorms passed through the state last night, accompanied with damaging high winds and, in some cases, hail. I was cutting trees out of our road soon after to make it passable, a neighbor lost 24 around his relatively small yard, many uprooted. That type of weather event can trigger trauma blight, where fire blight bacteria is moved to new abrasions and other wounds resulting from the storm damage.

Although the storm brought cooler temperatures, which will drop the bacterial inoculum levels in most orchards, that high inoculum of E. amylovera was around right before the storm. Many growers applied streptomycin in the past couple of days to protect against the infection that likely occurred to open blossoms as a result of last night’s wetting. Now I’m going to suggest, especially in high-risk blocks that had fire blight last year, getting out there again and putting on a second strep spray ASAP (as in, between now and tomorrow morning) to protect against trauma blight.

If you had hail or other damaging weather, make sure to contact your crop insurance agent within 72 hours.

Where trade names or commercial products are used for identification,

no discrimination is intended and no endorsement is implied.

Always read the label before using any pesticide.

The label is the legal document for the product use.

Disregard any information in this message if it is in conflict with the


The UVM Tree Fruit and Viticulture Program is supported by the

University of Vermont Agriculture Experiment Station, a USDA NIFA E-IPM

Grant, and USDA Risk Management Agency Funds.