Water quality effects on trinexapac‐ethyl performance in hybrid bermudagrass

Plain Language Summary Golf course superintendents use plant growth regulators (PGRs) to suppress growth, enhance turfgrass quality, save water, and maintain healthier, more resilient putting greens. Applicators often tank‐mix PGRs with micronutrients (Fe, Mn, Zn), macronutrients (Ca, Mg), or use spray water high in Ca and Mg (e.g., well water). These elements are divalent cations that can potentially interact with spray solutions. Although the effects of tank‐mixing divalent cations with herbicides are well‐documented, their effects on PGR performance are not. The objective of this study was to determine the effects of Ca, Fe, Mg, Mn, and Zn in spray solutions on the efficacy of trinexapac‐ethyl (Primo Maxx; Syngenta) when applied to hybrid bermudagrass. The results demonstrate that Primo Maxx effectively suppresses growth when tank‐mixed with divalent cations, allowing golf course managers to safely combine the PGR with micronutrients or apply it in hard water without compromising performance.