Optimum Seasonal Mowing Heights for Smooth Crabgrass Reduction in Tall Fescue Lawns

Cultural control methods for pest management are desirable as they can reduce pesticide use resulting in reduced costs and environmental impact. Previous research has shown increased mowing heights can reduce crabgrass ( Digitaria sp.) populations. However, seasonal mowing height adjustments may further decrease crabgrass populations as lower heights of cut can increase turf density during optimal growing conditions. An experiment was conducted to determine ideal mowing height combinations during summer vs. fall/spring for crabgrass reductions in a tall fescue ( Festuca arundinacea ) sward. A half rate of prodiamine was included as a split-plot treatment to determine if mowing height combinations could reduce the amount of pesticide required to control crabgrass. Four fall/spring mowing heights (1, 2, 3, and 4 inches) were combined with the same summer mowing heights such that all heights were represented in both seasons. Results indicate that seasonal mowing height variations did not provide any better reduction in crabgrass populations over only using higher heights of cut consistently throughout the year. Also, the half rate of prodiamine successfully controlled crabgrass in all mowing heights except the lowest mowing height during summer months.