Evaluation of Annual Bluegrass Control Programs for Bermudagrass Turf Overseeded with Perennial Ryegrass

Few herbicides are available that will selectively control annual bluegrass in a polyculture of bermudagrass overseeded with perennial ryegrass. Research was conducted to evaluate multifaceted annual bluegrass control programs in overseeded bermudagrass. Treatments included various combinations of four herbicides: foramsulfuron applied 2 wk prior to overseeding (WPO); ethofumesate and bispyribac-sodium (bispyribac) applied 12 or 12 followed by (fb) 15 wk after overseeding (WAO); and prodiamine applied 15 WAO to provide continued PRE annual bluegrass control. Foramsulfuron at 0.03 kg ha−1 applied 2 WPO controlled annual bluegrass 63% 28 WAO. Foramsulfuron fb ethofumesate or bispyribac applied 12 or 12 fb 15 WAO improved control to 91% or greater. Ethofumesate or bispyribac applied with prodiamine at 1.1 kg ha−1 at 15 WAO did not improve annual bluegrass control compared with ethofumesate or bispyribac treatments alone according to pairwise contrasts. Only bispyribac-containing treatments induced unacceptable perennial ryegrass injury. Bispyribac applied with prodiamine reduced perennial ryegrass cover greater than bispyribac alone according to pairwise contrast. These data indicate that ethofumesate or bispyribac applied sequentially 12 and 15 WPO can effectively control annual bluegrass in bermudagrass turf overseeded with perennial ryegrass. Nomenclature: Bispyribac, ethofumesate, foramsulfuron, prodiamine; annual bluegrass, Poa annua L.; bermudagrass, Cynodon dactylon (L.) Pers., ‘Riviera’; hybrid bermudagrass, Cynodon dacylon (L.) Pers. X C. transvaalensis Burtt-Davy, ‘Tifway’; perennial ryegrass (Lolium perenne L.) LOLPE ‘Palmer IV’