Creeping bentgrass is seasonally stressed from high summer temperatures and high humidity conditions in the desert southwest from June to mid-September. Golf greens typically show decreased stand density and poor performance by the end of this time. A preventative fungicide application program was evaluated for the prevention of summer stress typical under summer conditions. Four tank mixes composed of Alliete Signature mixed with either Chipco 26019, EXP10790A, EXP10702B, or Daconil Ultrex fungicides were applied every fourteen days from June 10 to September 17, 1997, on a 'Penncross' creeping bentgrass green maintained at 5/32". The Daconil Ultrex tank mix caused some initial injury and in general, the lightest turfgrass color and the lowest turfgrass quality. EXP10702B treated turf produced, on average, the darkest turf with the leading rank score for quality. The Chipco 26019 tank mix produced the largest seasonal clipping totals, which was greater than the check. No diseases occurred on treated or untreated turf. Root dry weights in mid-October varied as much as 40% among treatments, but was not statistically significant.

EXP31130A and EXP31598A were applied as repeat applications on June 5 and July 23, 1997 to perennial ryegrass maintained at 3.0 inches. Application rates were 0.18 and 0.36 lbs. AI/A (31130A) and 7.0 and 14.0 fl. oz/prod/A (31598A). Each treatment was applied with and without Sequestrene 338 iron chelate, at the rate of 0.1 oz/m². Untreated and iron-only controls were included in the test. Ryegrass was generally unaffected by either compound, under the conditions of this test. Inclusion of iron (in the tank mix) was more beneficial for EXP31598A, than for EXP31130A. Untreated controls generally had lower performance scores, than did turf which received either herbicide compound. Treatment effects for overall turfgrass quality were significant only on three of ten evaluation dates, and on one of ten evaluation dates for turfgrass color. In general both compounds appear safe to use on high cut perennial ryegrass turf under summer conditions in a desert environment.

Ronstar and Barricade herbicides were applied to bermudagrass prior to overseeding with perennial ryegrass. For the initial establishment of fall overseeded bermudagrass with perennial ryegrass, Barricade and Ronstar both showed decrease in establishment at thirty days after overseeding (October 26) when compared to the controls. Reductions in turfgrass density after overseeding were realized by all pre-emergence treatments in the mid to late fall, depending on the specific treatment. Ronstar applied in one application at 2.0 lbs AI/A noticeably reduced visual density at 30 and 65 days after overseeding, regardless of the application timing ( 6 vs. 8 weeks) before overseeding. Reductions in turfgrass quality paralleled the reduction in density. Barricade applied at 0.75 lbs AI/A at 6 WBOS showed decreased quality at 30 and 65 days after overseeding. This same treatment caused a noticeable decrease in overall plot density at thirty days after overseeding. At 65 days after overseeding (November 30), quality was not quite fully acceptable (quality mean = 5.8), but acceptable density was achieved (mean density = 6.3). Poa annua (PA) established itself quickly. By November 30 (65 days after overseeding) overseeded- untreated control plots had between 67%-77% Poa annua present. The maximum rate of PA control for Ronstar in March was 74% (showing 15% Poa plot cover) and 61% in April (34% Poa plot cover). This occurred for the 2.0 lb AI/A at 8 WBOS treatment, which was similar to the same rate applied 6 WBOS. Split sequence applications (pre and post) of Ronstar produced low PA control (28%-50%) over the season as measured, when compared to single applications which achieved the same 2 lbs AI/A rate. The greatest amount of PA control was achieved by Barricade applied at 0.75 lb AI/A at 6 WAOS (86%-94% control). No treatment achieved 95% control of PA on a season long basis. Poa pressure at the test site was uniform and heavy.

Sulfentrazone herbicide was applied to bermudagrass turf, prior to overseeding at 0.125, 0.250 and 0.375 lbs. AI/A. Sulfentrazone did not inhibit emergence of perennial ryegrass when applied two days before overseeding. Plots ranged from 92-100% cover (of perennial ryegrass) from December to the end of March (last evaluation). Turfgrass color was noticeably less at the 0.375 lb. AI/A rate, but not significantly different from that of the lower rate application treatments. Pre-emergence weed control based on non-overseeded controls ranged from 51-100% across Sulfentrazone treated turfs, from December 1996 to late March, 1997. The percent reduction in Poa annua due to overseeding (comparison of non-overseed vs. overseed controls) was 90%, 61% 67% and 65% in December, January, February and March, respectively. Initial screening shows favorable activity for Poa annua control, especially at the 0.375 lb. AI/A rate. Further evaluation is needed to assess Poa annua suppression from Sulfentrazone and its potential interaction with overseeding, before cultural management programs can be devised for Poa annua control in an overseed program.

Ronstar was applied at three rates (1.0, 2.0 and 4.0 lbs. AI/A) at 12, 10, 8, 6 and 4 weeks before overseeding bermudagrass turf with perennial ryegrass on October 20, 1997. On November 7, 1997 (18 DAS) Ronstar treated plots ranged from 20% to 81% for percent plot ryegrass coverage. The greatest mean ryegrass coverage occurred for the 2.0 lbs. rate/@ 12 WBOS. Among the 4 lbs. treatments, there was more or less a linear decrease for ryegrass establishment on a visual plot basis as the application time came closer to the overseeding date. On December 1, Ronstar treated field plots ranged from a low of 29% ryegrass cover (4 lbs./@ 4 WBOS) to 91% (2 lbs./@ 12 WBOS). Among the 4 lbs. treated plots, the 10 and 12 WBOS timing allowed for 82% and 75% mean plot cover respectively, by December 1 (42 DAS). Of the remaining treatments, the 2 lbs./@ 4 WBOS had 61% plot cover (ryegrass) while all other 1 lbs. and 2 lbs. plots had 80% or greater cover at this time. On December 15, 1997 (56 DAS), mean percent plot scores for percentage ryegrass cover ranged from 53% to 100%. The only plot which had significantly less plot cover was 4 lbs./@ 4 WBOS (53%). All other plots had 88% or greater ryegrass cover. Turfgrass color scores showed a significant Atreatment@ effect on December 15, but not on December 29, January 29, March 11 or on April 11. On December 29 (70 DAS), overall turfgrass quality scores ranged from 4.0 (unacceptable) to 7.8. Two treatments which were sub-par included 4 lbs./@ 6 WBOS (5.7 = marginal) and 4 lbs./@ 4 WBOS (4.0 = unacceptable). Treatments which had mean quality values of 7.0 or higher included; 1 lbs./@ 10 WBOS (7.8), 1 lbs./@ 6 WBOS (7.8), 2 lbs./@ 10 WBOS (7.5), 1 lbs./@ 8 WBOS (7.3), 2 lbs./@ 6 WBOS (7.3), 4 lbs./@ 12 WBOS (7.3) and 2 lbs./@ 12 WBOS (7.3). Weed pressure was inadequate to fully assess pre-emergence control of Poa annua. At the close of the test on April 11, 1998, weed control ranged from 8% to 100%. Plots with 90% or greater weed control included 2 lbs./@ 10 WBOS, 1 lbs./@ 4 WBOS, and 4 lbs./@ 12, 8, 6, and 4 WBOS. The 1.0 lbs. AI/A treatment was safe for perennial ryegrass at 12, 10, 8, 6, and 4 WBOS. The 2.0 lbs. AI/A treatment was safe for perennial ryegrass at 12, 10, and 8 weeks. The 4.0 lbs. AI/A treatment was safe at 12 and 10 WBOS.

Six treatments of pre-emergence herbicides were evaluated for their effects on the spring green-up of dormant non-overseeded bermudagrass turf. Plot composition (percent yellow, percent green, percent straw or dormant turf) components were affected by herbicides to various extents on March 27, April 20, and April 27. Percent plot yellow turf was least in occurrence for BARRICADE, PENDULUM, and SURFLAN at 25 days after the first treatment. At 25 days after the first application (March 27) PENDULUM produced the lowest amount of green turf (13%) among treated turfs. At 50 days after the first application (April 20) PENDULUM treated turf had the greatest amount of yellow turf (63%), and the least amount of green turf present (18%). Turfgrass color was affected by herbicide treatments (on June 2, 30 days after the second treatment). The TEAM-PRO product had the darkest noticeable turf at this time. Herbicides had no affect on: A) visual estimates of turfgrass density B) number of lateral (horizontal) green stolons in the turf mat C) number of subterranean rhizomes D) root pegging of surface stolons. Green-up responses were short-lived from the herbicides evaluated at product rates tested.

Tifgreen bermudagrass (328) has been used for greens in the Southwest for 40 years. Decreased mowing heights desired for tournament events can result in loss of turf quality and performance. A series of mowing and rolling events were devised and executed on a Tifgreen turf mowed at 5/32", in order to minimize the potential negative affects of a reduced mowing height of 1/8". All treatments were executed prior to mowing the turf at the new reduced height of 1/8". Significant treatment effects resulted from combinations of mowing and rolling for ball speed distance, when averaged over three evaluation dates. When averaged over all three evaluation dates, the single mow/no roll treatment [1x mow/0 roll] had the least ball roll distance (BRD) values. Mowing/rolling combinations which resulted in either three or four operations on Day 1 (1x mow/2x roll, 2x mow/2x roll and 2x mow/1x roll) had slightly greater BRD values than the operations which included two operations (2x mow/0x roll and 1x mow/1x roll). BRD values decreased from Day 1, Day 2 and Day 4 from 81.2", 80.3" to 73.4", respectively when average over all treatments. Single mowing at 5/32", followed by either a double or single rolling event prior to mowing to the new height of 1/8" on Day 1, resulted in the longest BRD values for Days 1 and 2. The effect of all cultural management treatments was diminished by Day 4.

PROXY (ethephon) and PRIMO (trinexepac-ethyl) were applied to ryegrass (as overseeded turf) in winter and early spring of 1999. PGR effect was assessed as reduction in clipping weight between mowings on eleven harvest dates. From March to April, the greatest percentage reductions were realized from all PGR treatments. Over the entire test period (March 5 to May 15), clipping reduction was rate dependent for PROXY with the 10.0 ounce rate producing a greater PGR effect (less clippings than that of PROXY at the 5.0 ounce rate). PRIMO treated turf (at the highest label rate of 1.0 ounce/product/1000 ft) generally produced the greatest clipping reductions, but lost affect in the middle of May when suppression (broke) was released. PROXY at the 10.0 ounce rate was closer to that of PRIMO for PGR effect than was PROXY at the 5.0 rate. All treatments produced less clippings than that of the control on nine of the eleven harvest events. PRIMO produced on average a noticeably darker color turf than PROXY treated turfs and that of the control plots as well. PROXY treated turf at the 10.0 ounce rate generally had similar overall quality turf when compared to PRIMO treated turf throughout the test. This was due to a high degree of plant uniformity among PROXY treated turf, versus the darker color enhancement realized from PRIMO. No PGR affected the initial stages of spring transition from ryegrass to bermuda by late May 1999.

Spring transition of ryegrass back to the underlying bermudagrass has become problematic for turfgrass managers in the Southwest. This is in part do to increased heat tolerance and shoot densities of newer ryegrass cultivars which predominate the market place. The chemical ethephon (Proxy for turf) was evaluated for use as a plant growth regulator (PGR) to enhance transition from perennial ryegrass to bermudagrass. Proxy was applied at either 5 or 10 ounce rates/1000 square ft, either before, during or after soil moisture stress was imposed on the overseeded turf. On the dates of July 6, 21, 19 and August 9 the greatest visible difference occurred among treatments for percent bermudagrass. These responses were not not statistically significant, however. The greatest transition response was achieved (in general) from Proxy applied at 10 the ounce rate, when applied "pre-stress". This treatment combination generally ranked highest for percent bermudagrass throughout the test. The second most beneficial treatment (in general) was that of Proxy at the 10 ounce rate when applied under "medium stress". From July 21 to August 9 this treatment essentially ranked second for the ryegrass to bermudagrass transition. The third most beneficial treatment (in general) was Proxy applied at the 10 ounce rate , applied "post stress". This treatment was applied the latest in the season ( June 16), which was 22 days after the entire test was fully irrigated (at the start of the test on May 23). Proxy applied "post stress" at the 10 ounce rate excelled in enhancing the ryegrass to bermudagrass transition from July 21 to July 29. When applied at either the 5 or 10 ounce product rates, the "low stress" application treatments had minimal affect for transition. These treatments ranked similar in response to that of the untreated - well watered controls. The "medium" stress plots receiving Proxy exhibited a greater affect on the ryegrass to bermuda transition, depending on the date of bermudagrass evaluation. Further testing should be conducted on lower mowed perennial ryegrass with a more aggressive underlying bermudagrass base, such as the popular Tifway 419.

The transition from perennial ryegrass back to bermudagrass is often problematic. Prolonged periods of ryegrass persistence and/or loss of complete turf is troublesome and not favorable to the reestablishment of the bermudagrass base. A group of select herbicides were applied in May 2000, to assess their response to enhance the removal of perennial ryegrass, and to enhance recovery of the bermudagrass. CORSAIR (Chlorosufuron) applied at 1.0 ounce/product/acre resulted in reduced turfgrass quality from three to six weeks after treatment, with a decrease in color at three weeks. This treatment caused moderate suppression of the turf and an enhanced transition from perennial ryegrass to Tifway (419). MANOR (Metsulfuron) applied at 0.4 ounce/product/acre caused a slight growth suppression, acceptable turfgrass color, but a noticeable decrease in turfgrass quality up to six weeks after application. MANOR increased turf density and minimized scalping by seven weeks after treatment (July 24, 2000). SURFLAN when applied at 1.5 lb AI/A, produced acceptable quality turf, no visible growth suppression, acceptable overseed turf quality and color. SURFLAN did not provide any affect as a transition agent in this test. KERB did not greatly enhance transition, and was slightly more effective at 0.5 lb AI/A, than at the 1.0 lb AI/A rate. Both rates of KERB produced acceptable turfgrass color throughout the test. Turfgrass quality diminished to low levels from July 18 to July 24, ranking lowest in quality. KERB treated turf tended to "scalp" more than other treated turfs and thinned the grass at the high rate of 0.50 lb AI/A. FIRST RATE applied at 75 grams AI/hectare caused slight visible suppression for two weeks after treatment, an acceptable quality turf (on six of seven evaluation dates), acceptable turfgrass color and turf density. FIRST RATE did enhance transition, but less so than CORSAIR, possibly less than MANOR, and certainly less than AEF 130630. PROXY was applied on four dates (four, three, two, and zero weeks prior to June 3), selected as a "calendar target" dates observe transition. PROXY when applied on May 13, provided a short transition effect, for a period of about two weeks. Applications made later had little effect whatsoever, on Spring transition back to bermudagrass. From May 19 to June 5, the two "early" applications of PROXY, generally increased turfgrass color and quality scores, most likely by having a PGR response on perennial ryegrass. AEF 130630 readily enhanced Spring transition from perennial ryegrass to Tifway (419) bermudagrass, especially in May and June. All three application rates caused visual suppression of the turf from May 19 until June 5. Turfgrass color and quality were affected by AEF 130630. The maximum expression occurred for the 0.42 ounce/product/M rate by May 25 (which remained until at least June 5). Mean color scores here were 5.3, on both dates. The high rate 0.64 ounce/product/M actually caused less color reductions in the turf (perhaps as a function of the quicker removal of ryegrass). Reduced turf quality resulted three weeks after treatment for both the low and high rates (means = 5.0). The turf was similar to that of the control plots, afterwards, and superior by both middle and late July time periods.