A few of my blueberries have, under unknown circumstances, started reddening as you can see in the pictures. It is all in one row. However, the plants that are in the surrounding area are perfect (big dark green leaves). I have 8,000 blueberry plants, but I have never seen this symptoms before. Literally out of the blue.
I have to say that the water pH is 6, the plants are in the low pH peet, I am using acidic fertilization by Yara (24-8-16 and 10-5-26), and we have done five protection preventive treatments against any diseases.
So I really take care of them. Is it possible that they just decide to give up on their life, or could you suggest what this might be?
Outside United States
I'd like to get a little more information about your situation:
-Where are these plants located?
-What varieties are showing these symptoms?
-What varieties are NOT showing symptoms?
-How old are these plants?
-Has the weather in your location been abnormally cool or warm?
-Do you have a soil test results that show soil pH and phosphorus and potassium levels, etc.?