Post Emergence Control of Smooth Crabgrass with Acclaim Extra and MACRO-SORB^® foliar

Study conducted by Dr. P. H. Dernoeden at University of Maryland, 1998

Procedure

Treatments consisted of Acclaim Extra 0.57EW applied at rates of 0.06 and 0.09 lb ai/A alone and each rate tank-mixed with MACRO-SORB^® foliar at 2 oz. per 1000 ft².  All treatments were applied July 2, 1998 when crabgrass was in the 3-leaves to 4-tiller (mostly 4-leaves – 2-tiller) stage.  Plots were 25 ft² and the percent of plot area covered with crabgrass was assessed on a 0 to 100% scale where 0 = no crabgrass and 100 = entire plot area covered with crabgrass.  Smooth crabgrass pressure was severe.  Treatments with crabgrass cover ratings exceeding 5.0% were considered commercially unacceptable.

Results

Percent of plot area covered with crabgrass on untreated plots on July 16, July 28, and August 12 was 34, 63, and 81%, respectively (data not shown on graph).  Data collected July 16 and July 28 indicated that Acclaim Extra alone or in combination with MACRO-SORB^® foliar provided good crabgrass knockdown.  By August 12, although no significant differences were observed among treatments, only Acclaim Extra + MACRO-SORB^® foliar (0.09 lb ai/A + 2.0 fl. oz./1000 ft²) maintained a commercially acceptable control (≤5% area of plot covered with crabgrass).

MACRO-SORB foliar enhances effectiveness of Acclaim Extra to control crabgrass

MACRO-SORB foliar has also enhanced effectiveness of commercially available broadleaf herbicides in studies conducted by Dr. T. Watschke at Penn State.