ABSTRACT
A 3-year study was conducted on a ‘Penncross’ creeping bentgrass (Agrostis stolonifera L.) golf course putting green in North Carolina, USA, to evaluate: 1) the effects of GA-inhibiting PGRs on the reduction of annual biotypes of Poa annua, and 2) the effects of the same PGRs on bentgrass quality. Two or three fall + two or three spring applications of paclobutrazol, flurprimidol, and trinexapac-ethyl were evaluated on a golf course with a high population of Poa annua. Paclobutrazol treatments consistently reduced the Poa annua population more than flurprimidol or trinexapac-ethyl. Paclobutrazol treatments also reduced bentgrass quality but reductions were in the acceptable range for turfgrass quality. Flurprimidol treatments provided only small reductions in the Poa annua population, and trinexapac-ethyl treatments consistently provided no population reductions. Trinexapac-ethyl had the least effect on bentgrass quality of the 3 PGRs utilized in this study. These results offer golf course superintendents a management tool to reduce this troublesome weed in bentgrass putting greens.
