By Pam Charbonneau
OMAFRA Turf Specialist

An evaluation took place on the efficacy of Juicy Lawn, Nature’s Weed and Feed, Par III and a turf fertilizer (25-3-20) to control broadleaf weeds in turf. Plots were located in a turf research area at the Guelph Turfgrass Institute. The site is an area of established turf (predominantly turf-type perennial ryegrass infested with dandelions, clover and other lawn weeds). It is maintained as a low maintenance turf with weekly mowing at 6 cm and no supplemental irrigation.

The treatments were two different formulations of sugar beet extract products that were applied at one rate, a complete turf fertilizer applied at one rate, Par III (a commercially available three-way broadleaf herbicide consisting of 2,4 D, mecoprop and dicamba) applied at one rate and an untreated control for a total of five treatments (see Table 1).  Each treatment was replicated four times in 5 x 5 m plots in a randomized complete block design. The percentage of weed cover was measured in each plot three times per season and all measurements were analysed by the appropriate statistical method.
 

Treatment	Application rate (mL 100 m-2)
Untreated control Par III (2,4 D, mecoprop and dicamba)	55 mL
Juicy Lawn (15-2-3)	1100 mL
Fertilizer (25-3-20)	800 g
Nature’s Weed and Feed	2000 mL

 

Application of the treatments

Juicy Lawn, Nature’s Weed and Feed and Par III treatments were applied with a Chapman RB2000 4 L hand held pump garden sprayer. Nature’s Weed and Feed was diluted 1:1 with water for a total volume of 4,000 mL/100m2. Juicy Lawn was applied at a ratio of 1:3 Juicy Lawn to water for a total volume of 4,400 mL/100m2 and the fertilizer was applied with a Scotts drop spreader set at #16 fertilizer setting. Par III was applied at label rate with 3,000 mL/100m2 of water. Juicy Lawn and Nature’s Weed and Feed were applied one to two weeks apart during spring (May) and fall (mid-Aug. to mid-Sept.). During the 2008 season, we were unable to obtain Nature’s Weed and Feed and Juicy Lawn was substituted for the Nature’s Weed and Feed treatment. Juicy Lawn and Nature’s Weed and Feed were applied on Aug. 15 and Sept. 7, 2005, May 29, June 12, Aug. 8, and Sept. 14, 2006, June 6, June  11, Oct. 11, and Oct.  24, 2007, May 23, June 2, Sept. 8, 2008 and Sept. 17, 2008.  Par III was applied on Aug. 15, 2005, June 7 and Sept. 28, 2006, June 28, 2007 and Oct. 12. 2007, July 8, 2008 and Sept. 18, 2008.  Fertilizer was applied on Aug. 15, 2005, June 12, and Sept. 14, 2006, June 10, 2007 and Aug. 13, 2007, June 9, 2008 and Sept. 18, 2008.  
 

Efficacy assessments

Efficacy assessments were made once in 2005, because the project began in the fall of that year and three times each year from 2006 to 2008.  Four randomized point quadrats, measuring 60 cm x 60 cm, with 25 points in each quadrat (points 10 cm apart), for a total of 100 points in each plot, were used to record estimated percent of broadleaf weed cover per plot at each assessment date. Efficacy assessments were made prior to the start of the experiment on Aug. 5, 2005. Efficacy assessment dates were Sept. 9, 2005, Nov. 14, 2005, May 23, 2006, July 5, 2006, Oct. 18, 2006, June 1, 2007, July 5, 2007, Nov. 7, 2007. The only data presented below are the dates where there were significant differences among the two beet juice products and fertilizer treatment (Table 1).
 

Conclusions

Par III was significantly different from all the other treatments at all rating dates and gave superior post-emergence broad-leaf weed control. When comparing the two beet juice extract products, Nature’s Weed and Feed performed significantly better than the fertilizer at one rating date (20-11-07) and Juicy Lawn performed significantly better than the nitrogen only plots on the final rating date (8-11-08). The post-emergence broad weed suppression from the two beet juice was not consistently better than fertilizer alone and was far inferior to Par III.

Acknowledgements: H. Carey, C. VanDamme, N. Dunn and A. Cummings.
 

Results

Per cent broadleaf weed cover
    (1) Mean percent broadleaf weed cover by point quadrat estimation. Means of 4 replicates; means within columns followed by the same letter are not significantly different (Fisher’s protected LSD, p=.05).

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Pam Charbonneau can be reached at 519-824-4120, ext. 52597, or by e-mail at pamela.charbonneau@on.ca.