Drought Stress can cause browning of blueberry leaves. Water demand for blueberries is typically highest in the Northeast during the month of July when average precipitation is very low.
When in fruit, the crop may be affected before onset of leaf symptoms. Blueberries do not wilt as readily as many other plants. Berries will shrivel and drop before leaves die.
More information:
- Drought Stress (Michigan State)
- Irrigation Options for Blueberries (Michigan State)
Use these resources if you need additional help with diagnosis and to find solutions to your problem.