Spring Establishment of Four Warm-Season Turfgrasses After Fall Indaziflam Applications

Indaziflam is an effective PRE herbicide for annual bluegrass control, but soil residual effects could inhibit spring turf establishment in treated areas. To test this hypothesis, field experiments were conducted to evaluate establishment of bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass after fall indaziflam applications. Lateral spread of turfgrasses from plugs in summer generally had no meaningful differences from treatments. However, high indaziflam rates (70 and 140 g ai ha(-1)) had approximately two-fold more nonrooted stolons than the nontreated control while low rates (17.5 and 35 g ha(-1)), oxadiazon at 3360 g ai ha(-1), and prodiamine at 840 g ai ha(-1) were similar to the nontreated. Indaziflam at 70 g ha(-1) and prodiamine applications in fall reduced sprig establishment of the four turf species from the nontreated control, but oxadiazon and low rates of indaziflam were similar. Bermudagrass establishment from seed was significantly reduced (20 to 50%) by indaziflam at 35 to 140 g ha(-1), prodiamine, and oxadiazon, on several dates, but the low rate of indaziflam was similar to the nontreated at 10 wk after seeding. Overall, fall indaziflam applications at 17.5 to 35 g ha(-1) appear safe on vegetative establishment of four warm-season turfgrasses in spring but reseeding bermudagrass in areas treated with rates > 17.5 g ha(-1) may cause unacceptable delays in growth.