April 3-7: Blossom Blight Infection Alert!

A photo of blossom blight on an apple flower

Please note that all predicted blossom blight infection events are current as of April 2, 2025 @ 8:45 pm. Environmental conditions may change and may impact fire blight risk.

Henderson County, NC

The EIP model on NEWA is calling for a high risk for blossom blight infection on 4/3, an infection event on 4/4, a high risk for infection on 4/5, an infection event on 4/6, and a high risk for infection on 4/7. On Saturday April 5, the only condition not present according to the model is a wetting event. Dew, a pesticide spray, or even a mist could cause an infection. If strep was sprayed on April 1 or earlier the predicted infection events do not change and I would encourage you to prepare to apply strep. The table below shows the predicted infection events if no streptomycin is sprayed. I've been playing with some strep application timing scenarios in NEWA to best advice you. First, I indicated in NEWA that strep was sprayed on 4/3. If you spray on April 3rd, you could go back in on Saturday (4/5) to cover the infection event predicted on Sunday and the high risk present on Saturday. This is the safest option IMHO and would cover you through at least Monday. If you are going this route, I'd suggest the 8 oz/100 gal Harbour rate (2.67 oz/100 gal FireWall 50) on April 3rd and then double that rate for the Saturday (4/5) spray. If you just can't swing it, a single application (the higher rate) on Saturday may do the trick, but it is risky. Another option would be to spray strep (lower rate) on Friday, which would cover you for the predicted infections on Friday and Saturday and then go in Monday with the higher rate and try to clean up the infection event on Sunday. In general, I don't love promoting "kick-back" applications as these types of sprays are believed to increase the rate of resistance selection.

Blossom Blight Infection EVents Henderson County NC

Polk County, NC

The EIP model on NEWA is calling for a high risk for blossom blight infection on 4/3, and infection events on 4/4, 4/5, 4/6, and 4/7. On Thursday April 3, the only condition not present for an infection event is that the EIP did not reach "100" (note-it's "95" so pretty darn close and I'd still be concerned). If strep was sprayed on April 1 or earlier the predicted infection events do not change and I would encourage you to prepare to apply strep. The table below shows the predicted infection events if no streptomycin is sprayed. I've been playing with some strep application timing scenarios in NEWA to best advice you and frankly this is pretty tricky. Even if apply strep on April 3rd, an infection event is still predicted for the next day! I think you're best bet is to apply streptomycin (8 oz/100 gal Harbour or 2.67 oz/100 gal FireWall 50 on April 3rd which will cover you for the high risk and knock down the bacterial populations some to help with the infection even on Friday. Then go back in Saturday with a high rate of strep to help cover the infection from Friday. Spraying strep on Saturday will drop you to "high risk" for infection on Sunday and Monday. I'd be comfortable with 72 hours of protection if no more flowers are opening so you should be ok through Monday unless conditions change.

Blossom Blight infection risk, Polk County NC

Wilkes County, NC

The EIP model on NEWA is calling for a high risk for blossom blight infection on 4/3, an infection event on 4/4, a high risk for infection on 4/5, an infection event on 4/6, and a high risk for infection on 4/7. On Saturday April 5 and Monday April 7, the only condition not present according to the model is a wetting event. Dew, a pesticide spray, or even a mist could cause an infection. If strep was sprayed on April 1 or earlier the predicted infection events do not change and I would encourage you to prepare to apply strep. The table below shows the predicted infection events if no streptomycin is sprayed. I've been playing with some strep application timing scenarios in NEWA to best advice you. First, I indicated in NEWA that strep was sprayed on 4/3. If you spray on April 3rd, you could go back in on Saturday (4/5) to cover the infection event predicted on Sunday and the high risk present on Saturday. This is the safest option IMHO and would cover you through at least Monday. If you are going this route, I'd suggest the 8 oz/100 gal Harbour rate (2.67 oz/100 gal FireWall 50) on April 3rd and then double that rate for the Saturday (4/5) spray. If you just can't swing it, a single application (the higher rate) on Saturday may do the trick, but it is risky. Another option would be to spray strep (lower rate) on Friday, which would cover you for the predicted infections on Friday and Saturday and then go in Monday with the higher rate and try to clean up the infection event on Sunday. In general, I don't love promoting "kick-back" applications as these types of sprays are believed to increase the rate of resistance selection. Also, this approach gives you no real added benefit compared to the single Saturday spray. Again, I would highly encourage you to do the 4/3 and 4/5 strep applications if possible, especially if fire blight has been a problem for you in the past.

Blossom Blight INfection events WIlkes County