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Application of Certainty*, Manor*, Monument*, Revolver*, TranXit, Kerb*, and flazasulfuron in early June eliminated most ryegrass in one month with the onset of high summer temperatures. Certainty at 0.06 lb a.i./A, Manor at 0.012 lb a.i./A, Monument at 0.0047 lb a.i./A, Revolver at 0.008 lb a.i./A, TranXit at 0.0078 lb a.i./A, and flazasulfuron at 0.0039 lb a.i./A performed equivalent to higher rates to effectively remove ryegrass when applied in June. The herbicides at the lower rate range were not as effective in early May when ryegrass tended to regrow in cooler temperatures. Spring transition was achieved by applying higher rates of TranXit* at 0.031 lb a.i./A and flazasulfuron at 0.0156 lb a.i./A in early May to completely remove perennial ryegrass. Kerb at 1.0 lb a.i./A was effective in removing 80% of the ryegrass with a May application and 90% in June.

Thirteen herbicide treatments were applied on May 8, 2006, on a golf course fairway to assess transition and turf quality effects. Initial injury to perennial ryegrass was most extreme for Tranxit GTA when applied at 1.0 oz/prod/acre and Katana applied at 2.0 oz/prod/acre. Katana resulted in the total elimination of ryegrass and resulted in a fully necrotic canopy (straw cover) within two weeks after application to July 19, 2006 (72 Days after treatment). The development and persistence of necrotic leaf tissue of perennial ryegrass (straw) had the greatest impact on decreasing overall turfgrass quality ratings. No treatment went through the summer without some loss of quality at some point, including the untreated control. Certainty had little or no effect on transition when applied once at the rate of 1.25 oz/prod/acre. Surflan was not effective in ryegrass transition. The tank mix of Transit and nicosulfuron applied at the rate of 0.25 oz/prod./A each, produced an enhanced transition with nominal quality. In similar fashion, Monument applied at 0.35 oz./A produced an enhanced transition with nominal quality. A rates used in this test, other treatments had either too slow of a transition or had poor and extended low quality turf scores from rapid development of dead ryegrass (straw) and subsequent slow bermudagrass re-establishment. The UTC turf maintained a high percentage of living green ryegrass into the summer and 20% live ryegrass on August 8, 2006 which is roughly six weeks before the next overseeding.

Ethofumesate as an emulsifiable concentrate (EC) formulation (Prograss*) demonstrated slightly more activity against Poa annua, though not statistically significant, than the suspension concentrate (SC) herbicide (PoaConstrictor*). Following two applications, P. annua control was equivalent for Prograss at 0.75 lb a.i./A and PoaConstrictor at 1.0 lb a.i./A at approximately one month later. Late season evaluations showed that Prograss at one-half the rate of PoaConstrictor gave acceptable P. annua control. Both products needed to be applied two times at 2.0 lb a.i./A to achieve better than acceptable P. annua control as spring transition occurred.

Velocity* at 20 g a.i./A provided P. annua control better than at 10 g a.i./A. Velocity at 20 or 30 g a.i./A offered similar P. annua control with a single application. Velocity at 20 g a.i./A with the addition of non-ionic surfactant Latron CS-7* or Primo*, P. annua control was almost similar to that of Prograss* at 80%. Velocity at 10 g a.i./A combinations or at 20 g a.i./A without additives gave less than 75% control.

Tenacity herbicide (mesotrione) was evaluated for use as both a pre-emergent and post- emergent herbicide in conjunction with fall overseeding of bermudagrass with perennial ryegrass. Tenacity herbicide, when applied @7 DBOS, 1 DBOS, at first mowing (2 WAOS) or 3 weeks after the first mowing (5 WAOS) did not cause a reduction in stand of perennial ryegrass compared to non-treated controls. There was essentially no difference in ryegrass emergence and cover for Tenacity when applied at the 2.0 oz. versus the 3.0 oz AI/A rate. When applied at these rates at both 7 DBOS and at the first mowing, treatments 1, 3, and 6 produced similar results. Overseeding occurred on October 16, 2007. Intense Poa annua pressure dominated the overseed ryegrass by late December, causing a decline in existing ryegrass cover. Only the latter applied treatments (of Prograss, or tank mixes which contained Prograss with Tenacity) regained sizable amounts of ryegrass by the end of February and early March. Percent weed control was ineffective for treatments which did not include Prograss herbicide. The split application of Prograss of 0.75 lbs AI/a applied @ 8 WAOS and again @ 12 WAOS resulted in the greatest amount of Poa annua control, and the greatest amount of ryegrass. Tenacity (mesotrione), when applied at rates and timings observed here, was safe for perennial ryegrass emergence, but ineffective on Poa annua pre-emergence and as a post emergent agent based on the subsequent growth of Poa annua.

Velocity herbicide was applied alone, or with mixtures of Tourney fungicide and/or Primo PGR for the post emergence control/suppression of Poa annua (var. annua) in bermudagrass overseeded with perennial ryegrass. When applied alone as a repeat applications, Velocity herbicide applied at 15 and 30 gm ai/a was safe on perennial ryegrass overseed (based on color response). Velocity was safe for the overseed ryegrass when tank mixed with Tourney fungicide, both with and without the addition of Primo PGR. Tourney fungicide when applied alone at either 8 or 16 oz./product/acre produced no negative affects. As expected, Primo alone produced a dark color turf (7.8, 7.5, 7.0, and 7.0) on all four dates, respectively. Several treatments caused moderate injury to the (AB) across the entire test period. These included Velocity alone at the 15 gm/ai/a rate, and Velocity @ 30 gm ai/a plus Tourney @ 8 oz.prod/acre. The greatest amount of injury to (AB) occurred on 3/11/2008 for Velocity at 30 gm ai/a, either with or without Tourney fungicide. Although visible injury to Poa annua resulted after treatments were applied, seed head suppression was the most consistent treatment response. While injury to the Poa was severe for some treatments (Velocity plus Tourney fungicide), the Poa annua did return, ranging from re-growth as "weak plants" to an actively growing turfs (as is sometimes typical after a surviving injury response). Based on results, perhaps a tank mix application of Velocity at 30 gm ai/a along with 8 oz. product/acre of Tourney and 6 oz./acre of Primo, followed by a repeat application 35 days later may provide the ultimate seed head suppression.

For pre-emergence control of Poa annua (PA), Dimension as the EC and 270 G (granular) formulations were applied either as single applications at 6 and 8 weeks before fall overseeding, followed by sequential applications of Barricade. Barricade was also applied 6 and 8 weeks before overseeding. The plots were overseeded on October 2, 2006 with a Citation III perennial ryegrass blend at the rate of 625 lbs PLS/A. When overseeded with perennial ryegrass: Both pre-emerge treatments of the 270G formulation, and Barricade applied at 0.77 lbs AI/A six weeks before overseed (6WB0S) had moderate to severe stunting. Both Dimension treatments (6 and 8 weeks BOS) had no apparent loss of vigor, and were equal in vigor with that of the non-treated turf. By mid December , the 270G treatments produced the least amount of ryegrass cover. Also on October 18, there was a slight reduction in ryegrass cover for Dimension and Barricade treated turfs. The single application treatments of Dimension produced slight/moderate percent weed control in February and March, which declined rapidly by the end of March. On March 15, Dimension applied at 32 ounces/product/acre at 6 and 8WBOS had a season maximum of 43%, and 20% weed control, respectively. Barricade applied at 0.77 lbs. product/A had the highest amounts of PA control realized in this test. The pre/post application of Barricade (alone) produced percent weed control values statistically similar to that of the single pre-emergence application of Barricade alone at either 6 or 8WBOS. The 270G treatments produced much higher levels of percent (PA) control than the liquid formulation on all three dates. In non-overseeded turf: Liquid Dimension treatments showed NO control whatsoever at 8WBOS. At 6WBOS, 24% PA weed control was the highest control achieved early on at the November 2 evaluation. Barricade, when applied once as a pre-emergence, had good to moderate percent PA weed control, which declined after December (45% in January) at the 6WBOS timing. The 270G treatments had very good initial weed control (as it did on the overseeded plots) with 93–97% weed control on November 2, 89% - 91% on November 17, and 71-80% weed control on December 7. The affect of overseed alone on suppression of PA was 72%, 60%, and 52% (16 Feb, 15 Mar, and 26 Mar).

TGR (paclobutrazole) was applied to both overseeded and non-overseeded turfs in repeat monthly applications at either 8.0 oz or 12.0 oz product/1000 ft² rates. Applications were made in repeat monthly intervals to apply either three, four or five repeat applications beginning in December 2007, and ending in April 2008. When applied as a post emergent PGR material, TGR caused only a slight decrease in turfgrass color and quality of overseeded turfs in March at the high (and repeated) rate of 12.0 oz/product/acre. This effect was short lived, as overseeded turfs for the remainder of the season maintained fully acceptable color and quality through the spring transition period. Tenacity turfs always had quality scores of 6.0 or higher throughout the test. Seed head suppression was realized from TGR, with greater head suppression at the 12.0 oz rate than that of the 8.0 oz rate. Bermudagrass transition among TGR treated turfs was not different from that of the untreated controls, whether the turfs were overseeded or not. On 20 June 2008, percent bermudagrass plot cover ranged from 29-58% for TGR treated turfs, 40% for Tenacity, while the overseeded UTC had 35%, on average. The percent bermudagrass increased quickly after a 2.0 lb. /N /M application on June 20, to 68% to 90% bermudagrass cover for TGR treated turfs (UTC = 83%). After a scalping event (from 1.25 inches to 0.50 inches) performed on July 1, percent bermudagrass decreased temporarily (from bermudagrass removal), but rebounded within 15 days to yield 96% to 99% bermudagrass cover by the close of the test on 31 July, 2008. Like wise, Tenacity alone did not inhibit transition, as Tenacity treated turfs had bermudagrass cover slightly greater than that of the overseeded controls.

Overseeding bermudagrass turf with perennial ryegrass is essentially a standard practice in south western turfgrass maintenance. This practice complicates (and often negates) the pre-emergence control of Poa annua (PA) which germinates within the overseeding window. Outplay (mesotrione) was applies as pre , post and pre+post applications to control PA in golf turf (overseed on October 2, 2006). Outplay was applied with Trimmit as a post emergence treatment. Barricade and Barricade + Monument were applied post emergence. On non overseeded turf: The greatest amount of (PA) weed control was achieved by the treatment of Barricade 16 ounce/product/acre (8WBOS) and Monument 16 gm (2WBOS) (Table 3). This treatment had no PA initially (2 November) 93% control on 17 November, and 7 December, 90% control on 4 January, dropping to 77% control by 16 February. Outplay applied pre-emergence as a sole treatment had little or no affect on PA, providing essentially no control. This was even true for the high rate of 16 ounces of product, applied 1 week before overseeding. Outplay applied both pre/post at eight ounces also had little effect on PA. The same was true for Outplay applied as two post emergence treatments [( 8 + 8 ) or (16 + 16) ounce rates] (Table 3). Prograss had a maximum weed control of 50% on January 4, sixteen days after its repeat application of 64 ounce. The post emergence tank mix of Outplay and Trimmit, followed by Trimmit alone had a maximum of 50% (PA) weed control on January 4, which declined afterwards. Overseeded Turf: Barricade and Barricade plus Monument had good control initially (94% 16 February), noting that the addition of Monument increased percent weed control by 10% in March (Table 8). Outplay applied alone as a pre-emergence product, had minimal control, with the high rate of 16 ounces applied 1 week before overseeding providing nominal weed control (65%, 41%, 58%) on 16 February, 15 March, 26 March, respectively. Outplay applied as a post emergence treatment only, exhibited good to moderate weed control, with the 16 and 16 ounce repeat treatments having better weed control than the 8 ounce plus 8 ounce treatments (applied 8 weeks and 12 weeks after overseeding, respectively). The 16 and 16 ounce treatment had 100%, 82% and 78% weed control on 16 February, 15 March, and 26 March, respectively (Table 8). Prograss applied twice as a post emergence provided similar levels of PA control (100%, 85%, 89%) on those same dates, respectively. Finally, when Outplay was applied as a post emergence treatment with Trimmit, weed control was good to moderate, providing 88%, 67%, and 78% weed control on overseeded turfs on 16 February, 15 March, and 26 March, respectively (Table 8). The affect of overseeding itself based on NTC means of overseeding and nonoverseed turfs (no herbicides) showed that overseeding alone suppressed PA by 93% on 16 February, 91% on 15 March and 59% on 26 March.