Efficacy and Longevity of Merit 75 WSP for Control of Black Turfgrass Ataenius Grubs
Summary: When applied at the recommended rate of 0.15 oz/1000 square feet, Merit 75 WP provided significantly better control of black turfgrass ataenius (BTA) grubs than no treatment for at least 35 days after treatment, and continued to show a non-significant trend towards improved grub control for four months. However, by six months after treatment, there were few differences between plots treated with Merit and those that were not treated. During periods of heavy grub pressure and high turf stress, control with Merit was insufficient to avoid some damage to greens. Merit treatments did not result in reduced damage from bird feeding.
Biological data on the BTA collected during this trial indicated that five or more generations occurred April and December, 1995. The highest density and most damaging grub generations occurred between July and September, 1995. Grub populations were found to be heavily aggregated, or clumped in their distribution. BTA grubs appeared to be more likely to occur on collars, or where soil was wet and water drainage was a problem. When BTA grub population data was compared with BTA adult population data obtained from a black light trap study also conducted at Los Coyotes Country Club, it was determined that grub infestations peaked 11 - 14 days after each adult peak.
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Principal Investigators: Wendy Gelernter and Larry Stowell
Cooperator: William Gallegos, Los Coyotes Country Club
Evaluation of Insecticides for Curative Control of Black Cutworms
Summary: In a replicated field trial on a bentgrass nursery at La Jolla Country Club, La Jolla, CA, a single curative treatment of various insecticides was evaluated for control of black cutworm larvae. Key results include:
- The best performing treatments included pyrethroid insecticides (Tempo, Scimitar, Talstar) and diazinon. A combination of Proclaim (emamectin benzoate) plus Avid (avermectin) also provided very good control.
- The experimental compound thiamethoxam (25 WG formulation) performed better than the non-treated check at the highest rate tested (0.3 oz/1000 sq ft), but not as well as the top performing products described above. At the two lower rates (0.15 oz and 0.20 oz/1000 sq ft), thiamethoxam did not perform as well as at the high rate.
- The addition of Proclaim to thiamethoxam somewhat improved the performance of thiamethoxam. In contrast, addition of Avid to thiamethoxam did not significantly improve the performance of thiamethoxam.
- The granular formulation of thiamethoxam performed significantly worse than a comparable rate of the WG formulation (0.0725 oz ai/1000 square feet), and was statistically indistinguishable from the check. This difference in performance between sprayable and granular formulations is typical for many insecticides, especially when foliar feeding insects such as black cutworms are involved.
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Principal Investigators: Wendy Gelernter, Ph.D. and Larry J. Stowell, Ph.D.
Cooperator: Bruce Duenow, La Jolla Country Club
Sponsors: Bayer, Zeneca, Novartis
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).
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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
