PACE Turf - Turfgrass Information Center

Evaluation of Primo Rates and Application Timing Strategies for Improved Transition and Turf Quality

Summary: A study was conducted on overseeded common bermudagrass fairways to determine the optimal rate, application timing and frequency of application of Primo to achieve improved Fall transition from common bermudagrass to ryegrass. A similar trial conducted in 1996/97 by the PACE Turfgrass Research Institute indicated that the highest quality overseeded turfgrass resulted when Primo applications (0.5 oz/1000 sq ft) were made at the time of the first ryegrass mowing. To confirm these results, a streamlined version of the study was repeated in 1997/98. Key results include:

  • Overall, a single application of the 0.5 oz or 0.75 oz/1000 sq ft rate of Primo L provided the most consistent positive results when the product was applied to ryegrass, 1 - 9 days after the 1st mow. In contrast, applications made according to Primo L label instructions (1-5 days before overseeding) had no positive effects on turfgrass quality. Based on two years of data supporting this conclusion, a change in label application timing recommendations should be considered for the Low Desert, where the unique renovation and overseeding strategies that are practiced may dictate modifications in product use patterns.
  • The turf quality improvements were observed 7-8 weeks after Primo applications were made, suggesting that the growth regulator effect of Primo on ryegrass, which typically lasts 4 weeks, only partly contributed to the results. Based on the data, it is likely that Primo applications made at the time of the first mowing caused significant and selective reductions in bermudagrass growth without a similar impact on ryegrass, allowing denser and more vigorous establishment of overseeded ryegrass in the treated plots.
  • Primo L treatments (0.5 - 2.0 oz/1000 sq ft) made to bermudagrass, 1 - 14 days before overseeding, had no positive effects on turfgrass quality. Again this was similar to results observed in 1996/97. However, applications made to bermudagrass may be advisable as a green waste management tool.
  • Double applications of Primo (an initial treatment of Primo prior to overseeding, followed by a second application after overseeding) did not appear to enhance the chances of improved ryegrass quality under the weather and overseeding conditions experienced in the Low Desert.
  • None of the treatments tested caused any negative effect on the Spring transition from ryegrass to bermudagrass.  This is in contrast to results seen in the previous year’s study.

Printable version of full report

Principal Investigators:  Wendy Gelernter, Ph.D. and Larry J. Stowell, Ph.D., CPAg

Cooperator:  Mike Kocour, The Springs Club

Sponsors: Hi-Lo Desert Golf Course Superintendents Association and Novartis

Kikuyugrass quality improvement using Primo growth regulator

Summary: Primo, at all rates tested, reduced clipping yields and improved turfgrass quality 28 days after treatment. The amount of clipping reduction increased with increasing rates of Primo. The 0.50 and 0.75 oz Primo/1000 sq ft rates provided 50% reduction in clippings 28 days after treatment (DAT). There was no significant difference between the 0.50 and 0.75 oz/1000 sq ft treatments at the 21 and 28 DAT ratings when clipping yields demonstrated the greatest reductions. Visual turfgrass quality was reduced in all treatments at the 7 and 14 DAT ratings compared to the non-treated check, but, visual quality of the treated plots surpassed the non-treated check at 28 DAT. Based upon these results, the 0.5 oz/1000 sq ft treatment provides the best performance at the lowest rate.

Printable version of full report

Principal Investigators:  Larry Stowell, Ph.D. and Wendy Gelernter, Ph.D.

Cooperator: Reed Yenny, CGCS Mesa Verde Country Club

Sponsor: Ciba

Soil Compaction: A Case Study at Candlewood Country Club

Summary: One method of measuring soil compaction, or strength, entails recording the pressure needed to force a rod (cone tip penetrometer) into a soil.  If the soil provides resistance of more than 300-400 psi, plant roots have difficulty or are unable to penetrate the soil. For this reason, plant roots are frequently found only in the top 2 3” of soil, where compaction is usually less than 300 psi. In this study, readings taken inside the sand-filled vertidrain holes, one day after vertidrain treatment showed that the vertidrain reduced compaction at depths of 3 - 5” from about 500 psi to less than 400 psi (Figure 1).  Five weeks later, we went back to evaluate compaction again, but it was difficult to identify vertidrain holes.  For this reason, the readings we obtained (Figure 2) were probably taken from areas between holes. As expected, readings remained unchanged at 500 psi at depths of 3 - 5”.  It is likely, however, that the compaction level in the vertidrain holes remained below 400 psi.  The common observation of deep roots in vertidrain holes supports this hypothesis. An additional advantage of vertidraining may be improved water infiltration. Even though compaction was not relieved in general throughout the green, the greens take water well in the summer indicating that water infiltration is one of the greatest benefits of this method.

Printable version of full report

Principal Investigator:  Larry Stowell, Ph.D., CPAg

Cooperator:  Mike Caranci, Candlewood Country Club

Sponsor:  PACE Turfgrass Research Institute

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