Weather in the Midwest has been hot, humid, and sometimes rainy. These conditions are a perfect breeding ground for strawberry root rots, says Annemiek Schilder, of Michigan State University Extension.
Schilder says leather rot, Phytopthora cactorum, can occur in cool, wet conditions. While anthracnose fruit rot favors the hot, humid conditions. In high heat, Mucor or Rhizopus may also occur.
“Spores are dispersed by rain or irrigation water splash and can land several feet from an infection source. The fungus can reproduce on leaves without symptoms, which may result in apparent rapid spread of the disease,” she writes. “Anthracnose fruit rot is favored by hot, humid weather and frequent rain or overhead irrigation. The optimum temperature for disease development is 80 degrees Fahrenheit and at least six hours of wetting is required for infection. The longer the fruit remains wet, the greater the risk of infection.”
Anthracnose fruit rot can be higher with berries grown in plastic mulch and spread by pickers or field equipment.