Fungal Disease in Bluegrass Lawns

Twenty years ago, it was a rarity to see fungal disease widespread across home lawns. These problems were usually found on high-stress sports fields, greens, and heavily watered fairways when climate conditions moved the needle into dangerous territory. With housing developments quickly emerging and with modern home construction typically having a negative effect on the soil quality, low fertility of exposed subsoil and severe soil compaction set up a perfect storm for fungal disease.

The most popular turfgrass for use in the home lawn is typically a cultivar of Kentucky Bluegrass, a cool-season grass that does not do well in light soil or heat. Unable to tolerate drought well, bluegrass sod suffers an injury and in its weakened state is susceptible, in fact, prone to disease. As another important variable, Iowa’s climate and ever-changing weather conditions are problematic. Kentucky Bluegrass prefers stability and by late spring, turfgrass is usually already under stress, well before drought conditions may cause concern. At this very pivotal time, even walking across the lawn in the afternoon heat can be the tipping point. Our summer season greets us with heat and humidity, both further stressing the turfgrass and creating the perfect environment for the pathogen to grow, all this compounding at the same time.