PACE Turf - Turfgrass Information Center

Effect of Primer Applications on Nutrient Leaching in Turfgrass Greens

Summary: A replicated experiment was designed to evaluate the effect of Primer on the leaching of nutrients on a Poa annua golf course green. Following six monthly applications of Primer at 6 oz/1000 square feet, analyses conducted on soil samples from 1, 2 and 4 inches depths revealed no significant differences between treated and untreated plots in levels of over 20 nutrients including, sodium, magnesium, calcium, total salts, and even the highly leachable potassium. In addition, no phytotoxicity and no effects on turf quality were observed in areas treated with Primer. On the basis of these results, multiple applications of Primer to turfgrass do not increase leaching of nutrients in the soil.

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

Cooperator: Mark Schaer, San Luis Rey Downs

Sponsor: Stan Kostka, Aquatrols

Pre-emergent Herbicides for Control of Smooth Crabgrass

Summary: In a replicated field trial conducted on a hybrid Bermudagrass tee at La Jolla County Club, La Jolla, CA, residual activity, various formulations, rates and application timings for the herbicides Dimension, Barricade, Ronstar and Pendulum were evaluated for pre-emergent control of smooth crabgrass, Digitaria ischaemum. Key results included:

  • In warm winter climates such as California, it is possible that applications of pre-emerge herbicides for control of crabgrass can be made later than the manufacturers currently recommend (current recommendations are to treat when soil temperatures reach 50 - 55° F), thus extending the activity of these products into the summer months. This is based on our observation that soil temperatures at La Jolla CC reached 50 - 55° F on 3/3/97, but crabgrass seedlings didn't emerge until 5/5/97--a full two months later.
  • The best performance (100% control for 4 1/2 months) came from Dimension 1EC at either 1.5 oz/1000 (applied once on 3/3/97) or 0.75 oz/1000 (applied twice on 3/3/97 and 5/5/97), Pendulum 60 DG, at 1.8 oz/1000 (applied once on 3/3/97), a single application of Barricade 65 WG, applied at 0.55 oz/1000, and split applications of Barricade 65 WG (applied 3/3/97 and 5/5/97) at either 0.28 oz/1000 followed by 0.28 oz/1000, or 0.37 oz, followed by 0.18 oz/1000.
  • Lower rates of Barricade did not perform as well as either the high rate of Barricade or the split applications of Barricade, and the granular formulation of Dimension did not perform as well as the Dimension 1EC formulation.
  • For reasons that are not clear, the performance of Ronstar 2G was equivalent to that of the non-treated control throughout the trial.
  • The most effective products had a residual activity of 140 days (4 1/2 months).

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

Cooperator: Bruce Duenow, La Jolla Country Club

Sponsors: Dennis Shepard, Novartis; Randy Smith, Rohm and Haas

Evaluation of Insecticides for Control of Black Turfgrass Ataenius Grubs

Summary: In a replicated field trial at Los Coyotes Country Club, Buena Park, CA, the insecticides halofenozide, imidacloprid and acephate were tested for control of black turfgrass ataenius grubs. Treatments performing better than the non-treated control included the high rate of Mach 2 G (69.6 oz/1000 square feet), the mid-rate of Mach 2 SC (2.2 oz/1000 square feet) and Merit 75 WSP (0.15 oz/1000 square feet). The highly clumped nature of ataenius infestations, and the relatively low population levels made separation of other treatment effects impossible. However, trends (non-significant) indicate that Pinpoint 15 G (acephate) and the 3.0 oz rate of Mach 2 SC also performed quite well.

A strong rate response for Mach 2 G was observed. Surprisingly, there was only a weak rate response for Mach 2 SC. All products showed some level of curative activity on grub populations that were present at the time of application. In addition, residual activity of up to two months was observed for Mach 2 SC (2.2 oz rate) and Mach 2 G (69.6 oz rate).

Full print version of report (124Kb)

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

Cooperators:Bill Gallegos, CGCS; Los Coyotes Country Club, Buena Park, CA

Sponsors:Darrin Allred, American Cyanamid; Bernard Olsen, Plant Sciences, Inc

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