Evaluation of Indaziflam and Non-Selective Herbicide Combinations for Native Warm Season Grass Safety and Maintenance on Golf Course Roughs.

Native Warm Season Grasses (NWSG) are a popular choice for low maintenance roughs on golf courses.  They require minimal inputs to maintain and provide wildlife habitat.  NWSG are slow to establish, thus weed competition can impede stand density.  Specticle (active ingredient indaziflam) is a pre-emergent herbicide with known control of many grass and broadleaf weeds, yet minimal research has been conducted on NWSG safety.  In 2015, a multi-site research study was established at The Preserve Golf Club near Vancleave, MS and at the R.R. Foil Plant Science Research Center near Starkville, MS to evaluate the safety of indaziflam and non-selective herbicide combinations on wiregrass (Aristida stricta) and indiangrass (Sorghastrum nutans), respectively.  Study sites were arranged in a randomized complete block design with 4 replicants.  Treatments include Specticle FLO (49 g indaziflam/ha) + Round-up Pro (3.8 kg glyphosate/ha), Specticle G (49 g indaziflam/ha) + Round-up Pro (3.8 kg glyphosate/ha), Specticle FLO (49 g indaziflam/ha), and Specticle Total (109 kg ai/A) and a non-treated.  Treatments were applied to individual plots at dormancy, spring transition, and during summer.  Plots were harvested in August and dry matter yield reductions were calculated relative to the non-treated check. 

A significant timing by herbicide interaction was present in both species.  In general dormant applications of Specticle alone and combinations with glyphosate were safe on wiregrass and indiangrass.  With the exception of dormant applied treatments, Specticle + glyphosate reduced wiregrass and indiangrass dry weight yield ≥ 38% and up to 100%. 

Results indicate Specticle utility in NWSG maintenance as a stand-alone product.  When in combination with glyphosate, Specticle applications should be made during dormancy. 

Future research will evaluate weed control within NWSG swards.