Happy Spring NC Apple Growers! Sorry to hit you with a Blossom Blight Infection Alert in the evening, but the weather forecasts have changed slightly. Higher temperatures and wetting events that were not predicted earlier in the week have reared their ugly head. Please see below for your predicted risk-remember that I cannot report for each individual farm throughout the state so please give me a call, text or email if you have any questions about your specific orchard.

According to the EIP model, a blossom blight infection event is predicted for March 27, 2026. An application of streptomycin (100 ppm) is advised in any blocks that have open flowers. As of this evening (March 26th) there is a high risk for blossom blight infection on March 31st. Be on the lookout-I will send an update on Monday, March 30th to address any updated risks.

Depending on elevation in Alexander and Wilkes Counties, the risk of blossom blight is slightly different for today (March 26) and Thursday (March 27). In the Taylorsville area (second table above) the EIP model on NEWA is calling for a blossom blight infection event on 3/26 and on 3/27. If streptomycin was not applied in blocks with open flowers on 3/26, I would suggest a strep application at the 200 ppm rate on 3/27. This higher rate should provide greater post-infection efficacy. At higher elevations (Lowe Orchards) in Wilkes County, a blossom blight infection event is predicted for March 27th. Consider an application of streptomycin (100 ppm) in blocks in bloom.

According to the EIP model, there is a high risk for blossom blight infection on March 27th. 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 you are making a pesticide application on March 27th, an application of streptomycin (100 ppm) is advised in any blocks that have open flowers. As of this evening (March 26th) there is a predicted blossom blight infection event on March 31st. Be on the lookout-I will send an update on Monday, March 30th to address any updated risks.

The situation in Henderson County gets a bit tricky compared to other counties in the state. The table above shows the risk of blossom blight in Edneyville, NC for blossom that opened on March 22nd or later. In this situation, there is a high risk for blossom blight infection. The only condition not being met is that the EIP value does not exceed 100. Recall, that the EIP value is related to the epiphitic population size of the fire blight pathogen, Erwinia amylovora growing on the stigmatic surface of the flower. Likely, flowers that opened on 3/22 or 3/23 and later did not have enough heating units to drive the bacteria populations beyond the 100 EIP value. While I did not include a second table, running the models on flowers that opened on 3/21 or earlier, suggest a blossom blight infection is predicted on 3/27. To keep things "easy" for you, I'd consider a streptomycin application (100ppm) on highly susceptible cultivars like 'Pink Lady' and 'Gala' and in blocks that had active fire blight infections last season.