It first grows on the root surface but later penetrates the tissue and invades the inner root tissue. Conditions in spring are optimal for turfgrass root growth, and even though fungal colonization is occurring, the turfgrass is able to absorb water and maintain growth. Therefore, foliar symptoms do not develop at this time. However, infected roots either die or become dysfunctional during the hot, dry summer months. Root growth is inhibited by high soil temperatures, and plants cannot rapidly replace diseased roots.
Infected plants are no longer able to supply adequate water to the foliage and the plant dies.
Circular patch symptoms develop because the fungus tends to grow radially out from a central infection point. The fungus can survive many years in the soil, and symptoms often develop yearly in the same location. Summer patch is an extremely difficult disease to control. Several cultural practices will help suppress disease development. Turfgrass should be maintained in a vigorous, but not overstimulated, growing condition.