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Help Needed — Fire Blight Samples

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Written by Dr. Youfu “Frank” Zhao, Professor & Endowed Chair in Bacterial diseases, WSU-IAREC, July 3, 2022.

The cold spring weather we experienced gave us optimism that fire blight may not be severe for this growing season. For most orchards, this probably is the case, which we all hope for. However, I learned that some have suffered worse fire blight than last season, which was very unfortunate. On the other hand, cold weather may prolong blossom period and also put off planting for late May, even June, which may result in late bloom. Severe weather (large hail and thunderstorm) in early June indeed caused great concerns of severe shoot blight. In addition, a very wet spring may make things worse.

In one of my WTFRC-funded projects, we will screen for and map antibiotic resistance in Washington orchards. My lab is currently coming in shape and ready to accept samples for testing antibiotic resistance in your orchard. If you indeed find fire blight disease in your orchard, please collect and send samples of fire blight-infected apples and pears to me for free screening of resistance to antibiotics. I will share the results with you, probably within a week or two of receiving samples. Or you can contact me and I can arrange to come out to your farm and collect samples.

Instructions for collecting samples:

  • Cut cankers, shoots, and leaves with obvious fire blight symptoms with several inches of healthy tissue and place in plastic zip bag.
  •  Store and ship with ice packs if possible.
  • Record the date, location, variety and history of antibiotic use in the block.
  • Ship to WSU-IAREC, 24106 N. Bunn Road, Prosser, Washington 99350, with attention to Frank Zhao.


Frank Zhao Portrait

Dr. Youfu “Frank” Zhao
Professor & Endowed Chair in Bacterial diseases, WSU-IAREC
Phone: 509-876-9284; 217-722-2197 (cell)

Funding and acknowledgments

We would like to that the WTFRC Apple Crop Protection for the support for this project.

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