Persistence of Rimsulfuron on Perennial Ryegrass (Lolium perenne) and Annual Bluegrass (Poa annua) Foliage

Abstract

Field studies have shown that rimsulfuron can move laterally with mower tires and injure neighboring cool-season grasses, indicating that persistent chemical can dislodge from turfgrass foliage. Laboratory studies were conducted to evaluate persistence and stability of14C rimsulfuron on perennial ryegrass and annual bluegrass foliage. Rimsulfuron was absorbed by annual bluegrass and perennial ryegrass equivalently, and persisted equally on foliage of each species. When extracted with a water rinse, 57% of applied rimsulfuron was recovered after 10 min, and 42% of applied rimsulfuron was recovered after 96 h. Rimsulfuron was stable 4 d after application based on comparison of rinse water chromatograms to stock solution chromatograms. These data indicate that appreciable rimsulfuron persists on turf foliage for 4 d. Thus, limiting traffic on treated areas for several hours to allow drying is not a viable method to prevent lateral relocation of rimsulfuron, and subsequent injury to cool-season turfgrasses.

Distance and Severity of Creeping Bentgrass Injury from Mower-Dislodged Sulfonylurea Herbicides

“…), and prostrate knotweed (Polygonum aviculare L.) (Askew et al 2006a) the higher rates may not be necessary to control important weeds. Barker et al (2006) found that 51 and 43% of applied rimsulfuron was water extractable from annual bluegrass and perennial ryegrass leaf surfaces 20 and 68 HAT, respectively. This decrease in available product may partially account for reduced injury from flazasulfuron and foramsulfuron tracked 20 HAT and 68 HAT.…”

“…Many golf superintendents have noted herbicide injury from sulfonylurea herbicides dislodged by equipment or foot traffic and deposited on adjacent creeping bentgrass (W. B. Gallager and M. Vaughn, personal communication). Turfgrass injury in these cases was caused by herbicides that were resuspended in dew on the leaf surface and contaminated tires or shoes that traversed the treated area and then an untreated bentgrass area (Barker et al 2006). Turfgrass injury by dislodging and depositing herbicide feet or equipment tires is known as ''tracking'' by researchers and golf course superintendents.…”

“…For instance, 20 h after rimsulfuron application Solanum sp. had absorbed 56 to 73% of applied product (Ackley et al 1999), and perennial ryegrass and annual bluegrass (Poa annua L.) had absorbed 48% of applied product (Barker et al 2006). Likewise, different corn (Zea mays L.) hybrids had absorbed between 60 and 80% of applied foramsulfuron 1 d after treatment (Bunting et al 2004).…”

“…Limited research has been conducted to assess parent herbicide persistence on leaf surfaces after spray applications to turfgrass. Of rimsulfuron applied to annual bluegrass and perennial ryegrass foliage, 52% was extracted with water after 24 h and 5% less was extracted after each 24 h thereafter (Barker et al 2006).…”

Effects of Rimsulfuron Lateral Relocation on Creeping Bentgrass (Agrostis stolonifera)

“…Thus, bentgrass plants likely absorbed enough rimsulfuron in that short time period to cause injury. Rapid absorption has been measured in studies on nightshade in which approximately 50% of applied rimsulfuron absorbed into plant foliage within 6 h (Ackley et al 1999), and Barker et al (2004) indicated 40% of applied 14 C-rimsulfuron was absorbed by perennial ryegrass and annual bluegrass in 10 min, a Rimsulfuron was applied at 17.5 and 35 g/ha with 0.25% nonionic surfactant to adjacent perennial ryegrass. For remedial treatments, only the high rate of rimsulfuron was evaluated.…”