Native Turfgrass Tolerance to Indaziflam Applications.

Native turfgrass systems contain a variety of species vegetation and can reduce fertility, fuel and water inputs. Due to diverse flora, weed control can be problematic. Multiple research trials were conducted in the Manhattan, KS greater area from 2014 to 2016 to determine native and naturalized turfgrass species tolerance to indaziflam applications. Evaluated species included; little bluestem (Schizachyrium scoparium), big bluestem (Andropogon gerardii), indiangrass (Sorghastrum nutans) and tall fescue (Lolium arundinaceum). Evaluated indaziflam (49 g ha^-1) applications included; formulation (Specticle FLO and Specticle G), application method (broadcast, over-the-top and directed spray), application timing (spring, summer, fall, winter) and vegetation management (mown, non-mown, burned and non-burned). Additional treatments Specticle Total (indaziflam + diquat + glyphosate) at 11.9 kg ai ha^-1 and 23.8 kg ai ha^-1, Snapshot 2.5 (4.4 kg trifluralin ha^-1  + 1.1 kg isoxaben ha^-1), Barricade 65WG (0.56 kg prodiamine ha^-1) and a non-treated control was included for comparison. Liquid applications were applied using a CO₂ pressurized backpack sprayer calibrated to deliver 375 L ha^-1 at 221 kPa. Each study site was arranged in a randomized complete block with 4 replications. Plant tolerance was evaluated on a 1-10 scale (1 = significant damage, 6 = minimal acceptable quality and 10 = quality equal or better than the non-treated). Phytotoxicity was evaluated on a 0-100% scale.  Evaluations were conducted bi-weekly for 6 weeks after each application.  Analysis of variance was performed in SAS and means were separated according to Fisher’s Protected LSD at 0.05 significance level.  Results indicated that evaluated species are tolerant to indaziflam applications throughout the year. Specticle Total applications should be avoided on tall fescue throughout the year and during spring, summer and fall to little bluestem, big bluestem and indiangrass.  Future research will evaluate additional native species and weed control.