Symptoms

• If blueberry plants stand in water for several days in a row, they may develop root rot, a disease also known as phytophthora. The disease attacks the roots of the plant, turning them brown or black. The plant shows signs of the disease with leaves that turn red. The plant may also experience defoliation, branch dieback and stunted growth.
  
  

Cycle

• Phytophthora comes from a water mold. The fungus remains active in soil that does not drain well. The disease also occurs in heavy clay soils. The fungus stays in the soil for long periods.
  
  

Prevention/Solution

• Gardeners should avoid planting blueberries in soil that does not drain well. One option includes growing your bushes on raised mounds to help the water drain away from the plants. Fungicide applications used twice per year may help eliminate the problem.