Postemergent Annual Bluegrass Control in Dormant Nonoverseeded Bermudagrass Turf

Abstract

<jats:p>Annual bluegrass (<jats:italic>Poa annua</jats:italic> L.) can be a troublesome weed to control in established turfgrass stands; it has developed herbicide resistance after repeated use of products with similar modes of action, and several new herbicides have been registered for use on turfgrasses. Four field studies were conducted near Clemson, S.C., from 2003 through 2005 to evaluate postemergence annual bluegrass control in dormant, nonoverseeded bermudagrass [<jats:italic>Cynodon dactylon</jats:italic> (L.) Pers.] turf using various herbicides applied in either December or February of each year and rated in the spring. Annual bluegrass control can be accomplished in dormant, nonoverseeded bermudagrass turf using a wide range of products applied in either December or February. Flazasulfuron, foramsulfuron, glufosinate, glufosinate + clethodim, glufosinate + glyphosate, glyphosate + clethodim, glyphosate + diquat, pronamide, rimsulfuron, and trifloxysulfuron provided 87% or greater annual bluegrass control regardless of application timing. Imazaquin and simazine controlled annual bluegrass greater than 85% when applied in December but less than 80% when applied in February. Glyphosate provided 93% annual bluegrass control when applied in February but only 72% control with December applications. No detrimental effects on bermudagrass spring greenup were observed for any herbicide treatment or application time. The availability of several effective herbicide options with differing modes of action provides turfgrass managers with the opportunity to use herbicide rotations that may prevent, or at least delay, the development of resistant annual bluegrass populations to these chemical products.</jats:p>

Flazasulfuron Tank Mixtures with Amicarbazone for Annual Bluegrass Control in Seashore Paspalum

“…Single applications at the early timing in 2012 were probably less effective than other years due to warmer temperatures and increased annual bluegrass growth in March. Similar annual bluegrass control has been reported from sequential flazasulfuron treatments at 53 g ha −1 in December and February on dormant bermudagrass (22).…”

“…Similar control has been noted with pronamide at 50% greenup in ‘Sea Isle 1’ seashore paspalum (18). Researchers have also noted good (87%) to excellent (99%) control of annual bluegrass from pronamide applied at bermudagrass dormancy (22).…”

“…For example, foramsulfuron, rimsulfuron, and trifloxysulfuron are effective POST herbicides for annual bluegrass control in bermudagrass ( Cynodon dactylon L.) and zoysiagrass ( Zoysia spp. ), but may cause excessive injury (>20%) to seashore paspalum (12, 21, 22, 25). Ethofumesate has potential for use in seashore paspalum, but applications are often injurious and are limited to early POST timings for annual bluegrass control (4, 11, 12, 25).…”

“…Flazasulfuron has potential for use in seashore paspalum during active growth for weed control and growth regulation, but safety of applications during spring greenup for annual bluegrass control has received limited investigation (18). Flazasulfuron often requires sequential applications to maximize efficacy for annual bluegrass control, especially in late winter, and could increase potential for injury to seashore paspalum (22).…”

Tolerance of Three Clovers (Trifoliumspp.) to Common Herbicides

“…Pronamide reduced the flower density of small hop clover by 42%, suggesting a possible selective option for suppressing small hop clover present as a weed within clover seed production. Pronamide can be applied to nonresidential turf for PRE and POST control of common grass and broadleaf weeds, including annual bluegrass (Poa annua L.) (Anonymous 2009b; Toler et al 2007). Pronamide is also intended for fall or winter applications to clover and several other leguminous crops (Anonymous, 2009a).…”