Although infected roots and crowns may be extensively discolored, microscopic examination of the tissue is required to detect the presence of Pythium in the root tissue. The mycelium or spores of Pythium spp. The spores can germinate and infect the grass plant within an hour or two. Disease development occurs rapidly from these centers of origin by a cobweb-like, mycelial growth of the fungus from leaf to leaf. Rapid spread occurs when the mycelial strands or spores are moved by water or equipment across the turf.
Cultural practices can go a long way toward preventing pythium blight.
Good water management is very important in reducing disease potential. Increasing the mowing height and other practices that promote root growth may lessen the damage from pythium root rot. During extended periods of warm, humid weather, a preventive fungicide program may be needed to check the development of Pythium . Applications of fungicides recommended for control of Pythium blight should be made to areas with a history of Pythium activity when conditions are favorable for development or when symptoms first appear. Repeat applications as necessary.