OBJECTIVE: To compare the efficacy of Primo using several adjuvants on tall fescue
and Kentucky bluegrass.
PERSONNEL: Ward Upham and Jack Fry
SPONSOR: Ciba
MATERIALS AND METHODS:
The KSU Rocky Ford Turfgrass Research Center near Manhattan, KS, was used for this study. The same protocol was used for two species of turfgrass: 'Amigo' tall fescue and 'Glade' Kentucky bluegrass. Turf was well watered and maintained at a height of 3 inches, and no fertilizer was applied during the course of the study.
Plot size was 6 x 6 feet, and the experimental design was a randomized complete block with three replications. All treatments were applied on August 17, 1995. Conditions at the time of application were 83°F, wind at 4 mph, and a relative humidity of 25%.
Treatments 2 through 7 were applied with a backpack CO2 sprayer equipped with 8004VS flat-fan nozzles and calibrated to deliver 60 GPA (1.4 gal/1000 sq ft) at 35 psi. Treatments 8 and 9 involved the use of Thinvert and a low volume nozzle calibrated to deliver 2.8 gal/a. The low volume nozzle was used much like a 'Chemlawn' gun with the nozzle being about 3 ft above ground level during application.
Treatments calling for a 1X rate received Primo at 0.75 oz of product per 1000 sq ft. The 0.5 rate was half of that amount. Adjuvants were mixed at the rate of 0.5% v/v.
Density was rated visually on a 0 to 9 scale, with 9 being the most dense. Quality was also rated on the same scale, with 9 being the best and 0 equaling totally brown turfgrass. Clipping weight was determined by cutting one swath across each plot with a Toro 21 in. walk- behind mower and collecting the clippings. The clippings were weighed after being dried thoroughly.
Density was rated at the time of application and at 5 WAT (weeks after treatment). Quality ratings and clipping yields were taken weekly for 5 weeks. Quality ratings were taken immediately after mowing.
RESULTS:
Tall Fescue
Density: No differences occurred among treatments for either of the rating periods (initial and 5 WAT).
Quality: No significant differences occured among treatments for either the first or fifth WAT rating periods. The Primo treatments without adjuvants (Treatments 6 and 7) were consistently rated lower than all other treatments for the remaining weeks (Table 1). Thinvert by
itself (Treatment 8) showed no significant differences when compared to the Check plots. Thinvert + Primo (Treatment 9) was significantly lower in quality than the Check at weeks 2 and 3 but not at weeks 1, 4, and 5. All treatments provided acceptable quality (rating „ 6.0) except for Treatment 6 at week 4.
Clipping Yield: No significant differences occurred among treatments for every week except week 5. Though Treatment 7 (Primo @ 1X) was consistently at the lower end of clipping yields, no significant differences occurred among treatments 2 through 7 on any rating date. However, Treatment 9 (Primo + Thinvert) consistently produced more clippings than treatments 2 through 7 but less than treatments 1 and 8 (Check and Thinvert plots, respectively). Treatments 1 and 8 consistently produced more clippings than treatments 2 through 7 for every week except week 5.
Kentucky Bluegrass
Density: No differences occurred among treatments for either of the rating periods (initial and 5 WAT).
Quality: No significant differences occurred among treatments for either the first, fourth, or fifth WAT rating periods (Table 2). Treatment 9 (Thinvert + Primo) showed the lowest quality ratings for weeks 2 through 4, with weeks 3 and 4 being of less than acceptable quality ( a rating of <6 was deemed unacceptable). The only other treatment to be rated less than acceptable was Treatment 7 (Primo @ 1X) at week 3. On weeks 2 and 3, all treatments were of significantly lower qualtiy than treatments 1 and 8 (Check and Thinvert, respectively) except Treatment 3 (Adjuvant 2 + Primo) at week 3.
Clipping Yield: No significant differences occurred among treatments for every week except week 5. Treatments 7 and 9 (Primo @ 1X and Thinvert + Primo, respectively) tended to produce the least clippings with significantly less than the Check for weeks 1 through 4. Treatments 2 through 7 and treatment 9 produced significantly fewer clippings than the Check at weeks 2 and 3. Results from weeks 1 and 4 were more mixed.
| Table 1: Quality and clipping yields of 'Amigo' tall fescue under various treatments containing Primo at Manhattan, KS, 1995. | |||||||||||||||
| Treatment | Adjuvant | Rate of Primo | Quality* | Clippings Yields ** | |||||||||||
| Weeks after Treatment | Weeks After Treatment | ||||||||||||||
| 1 | 2 | 3 | 4 | 5 | 1 | 2 | 3 | 4 | 5 | ||||||
| 1(Check) | ---- | ---- | 7.7 | 8.7 | 7.7 | 8.0 | 8.0 | 17.2 | 13.6 | 19.3 | 19.1 | 14.1 | |||
| 2 | 1 | 0.5X | 8.0 | 7.3 | 7.0 | 7.3 | 7.3 | 7.9 | 7.0 | 4.5 | 10.6 | 12.1 | |||
| 3 | 2 | 0.5X | 7.3 | 7.7 | 6.7 | 7.7 | 7.7 | 10.7 | 7.2 | 6.6 | 12.1 | 11.5 | |||
| 4 | 3 | 0.5X | 7.7 | 8.0 | 6.3 | 7.3 | 7.3 | 10.8 | 5.6 | 5.5 | 11.7 | 11.2 | |||
| 5 | 4 | 0.5X | 7.7 | 8.0 | 7.0 | 8.0 | 8.0 | 9.9 | 5.7 | 6.2 | 12.5 | 10.4 | |||
| 6 | ---- | 0.5X | 7.7 | 7.0 | 6.0 | 5.3 | 7.0 | 10.0 | 5.7 | 4.8 | 8.1 | 10.7 | |||
| 7 | ---- | 1X | 7.0 | 7.0 | 6.0 | 6.7 | 7.7 | 6.9 | 5.5 | 3.9 | 8.5 | 10.2 | |||
| 8 | Thinvert | ---- | 8.0 | 9.0 | 8.0 | 8.0 | 8.0 | 16.0 | 14.8 | 20.8 | 19.5 | 11.9 | |||
| 9 | Thinvert | 1X | 7.7 | 8.0 | 7.0 | 7.3 | 7.3 | 12.1 | 10.6 | 12.3 | 15.0 | 12.1 | |||
| MSD | ---- | ---- | NS*** | 0.7 | 0.7 | 1.0 | NS | 4.0 | 4.1 | 7.5 | 6.5 | NS | |||
| Table 2: Quality and clipping yields of 'Glade' Kentucky bluegrass under various treatments containing Primo at Manhattan, KS, 1995. | |||||||||||||
| Treatment | Adjuvant | Rate of Primo | Quality* | Clippings Yields ** | |||||||||
| Weeks after Treatment | Weeks after Treatment | ||||||||||||
| 1 | 2 | 3 | 4 | 5 | 1 | 2 | 3 | 4 | 5 | ||||
| 1(Check) | ---- | ---- | 8.0 | 9.0 | 8.0 | 6.7 | 8.0 | 10. 7 | 17.2 | 13.5 | 16.4 | 16.2 | |
| 2 | 1 | 0.5X | 7.3 | 7.3 | 6.7 | 7.0 | 7.3 | 7.2 | 7.9 | 2.9 | 11.5 | 12.3 | |
| 3 | 2 | 0.5X | 7.7 | 7.7 | 7.3 | 7.3 | 8.0 | 9.3 | 10.7 | 4.3 | 13.9 | 17.6 | |
| 4 | 3 | 0.5X | 7.3 | 7.3 | 7.0 | 6.3 | 7.7 | 9.8 | 10.8 | 3.9 | 11.5 | 16.9 | |
| 5 | 4 | 0.5X | 7.7 | 7.3 | 6.7 | 7.3 | 7.7 | 8.6 | 9.9 | 3.6 | 11.3 | 14.8 | |
| 6 | ---- | 0.5X | 7.7 | 7.3 | 6.3 | 7.3 | 7.3 | 9.4 | 10.0 | 3.8 | 7.2 | 11.8 | |
| 7 | ---- | 1X | 7.0 | 7.3 | 5.7 | 7.0 | 7.3 | 7.0 | 6.9 | 2.2 | 6.3 | 11.9 | |
| 8 | Thinvert | ---- | 8.0 | 8.7 | 8.0 | 6.7 | 8.0 | 13. 8 | 16.0 | 15.3 | 17.5 | 17.2 | |
| 9 | Thinvert | 1X | 7.0 | 6.7 | 5.3 | 5.7 | 7.3 | 5.7 | 12.1 | 2.9 | 7.0 | 9.7 | |
| MSD | ---- | ---- | NS*** | 1.3 | 0.7 | 1.8 | NS | 2.9 | 4.2 | 4.7 | 7.8 | NS | |