Excess watering, particularly in the early evening, may extend the duration of leaf wetness long enough for significant pathogen activity. Pythium blight severity increases sharply as day and night temperatures rise above the minimum for disease development. Several successive warm nights greatly increase the chances of a disease outbreak. Cool-season Pythium blight, which occurs at temperatures of 55 to 65 degrees F, has been seen in late fall and early winter on the bentgrass greens and tees of several Alabama golf courses. Pythium seed rot and seedling disease often occur during weather conditions that do not favor rapid seed germination and seedling growth.
Moisture is among the most critical factors influencing disease development.
Greens, tees, and other disease-prone turf should have good surface and subsurface drainage. Water early in the day, because watering in the early evening may increase the risk of disease by greatly lengthening the time the foliage remains wet. Increasing air circulation by selective placement or pruning of trees and shrubs will speed evaporation of water from the turf canopy, thereby reducing the risk of disease. Avoid overusing nitrogen fertilizers. Maintain balanced soil fertility by following soil test recommendations.