Q: What are the symptoms of black rot? What causes black rot and how do I deal with it? Is it contagious
A: There are two black rots, one cool weather type and one warm-weather form, each caused by a different blade. They are contagious and can be spread. The warm-weather type is the most serious because it can take an entire plant in three days. Keep the foliage dry, water only when necessary and spray with fungicide such as Physan 20.