Reducing Reliance on Pesticides in Turfgrass
Lowering the seeding rates can reduce the amount of pesticides and fertilizers needed for new turfgrass stands
Turfgrass is a highly managed commodity, especially in high income-generating settings like golf courses. Turfgrass managers may be reluctant to use IPM recommendations during the establishment of new golf greens, when pesticide and nutrient inputs are often substantial. Cornell turf specialist Frank Rossi explains that "They fear that IPM will compromise the aesthetics or functionality of the turf."
In the face of tremendous economic pressure to produce new grass quickly, turfgrass managers often increase grass seed rates above normal levels. Reducing seed rates sounds intuitively wrong in such circumstances, but the preliminary work of Rossi and of Eric Nelson, also of Cornell, indicates that it's the best move. Their data show that moderate seed rates actually lead to healthier stands than those achieved by excessive seeding. Crowding the seedlings apparently makes them more susceptible to diseases. This, in turn, means that supplemental fertilizer and fungicides will be required in high-seed areas to maintain the grass.
Visual cover ratings by Rossi and Nelson showed that the higher seed rate plots exhibited more rapid growth initially. But by six weeks after planting--about 40 percent of the way through the establishment phase for turfgrass--visual cover ratings were equalized among the plots. There was no benefit from the increased seed rates.
Absent any aesthetic arguments for or against various seed rates, the decision on how much seed to use should take into account the following advantages of low seed rates: 1) disease incidence tends to be less; 2) maintenance costs are lower due to lessened reliance on pesticides and fertilizers; and 3) ability to produce tillers (daughter plants that grow from the base of grass plants) is enhanced, leading to better traffic tolerance. More research is needed to verify these results, but these first-year results should alert turfgrass managers to some new ways to handle the pressures of the turf establishment phase.