INTEGRATED WEED MANAGEMENT SYSTEMS FOR ORGANIC AND CONVENTIONAL CROPS OF THE SOUTHEASTERN COASTAL PLAIN
Location: Crop Protection and Management Research
Title: Preemergence herbicides influence sprig establishment of 'TifEagle' bermudagrass
Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 11, 2012
Publication Date: July 2, 2012
Citation: McCullough, P.E., Schwartz, B.M., Grey, T.L., Webster, T.M. 2012. Preemergence herbicides influence sprig establishment of 'TifEagle' bermudagrass. Weed Technology. 26(2):300-303.
Interpretive Summary: Hybrid bermudagrass is widely used in the warm-humid climatic regions for golf course putting greens. Traditional bermudagrass putting green cultivars such as ‘Tifdwarf’ and ‘Tifgreen’ only tolerate long-term mowing heights of 4.8 mm or higher; producing inferior playing surfaces compared to creeping bentgrass (Agrostis stolonifera L.) greens. Ultradwarf bermudagrass cultivars are improved selections that tolerate long-term mowing heights of 3.2 mm or lower, creating fine textured golf greens comparable to bentgrass. Sprigging bermudagrass putting greens is generally more economical than establishing from sod, but sprigs require high fertilization, regular irrigation to promote growth, and effective weed control. Most preemergence (PRE) herbicides used in mature bermudagrass are not applicable during sprig establishment due to excessive injury and potential to inhibit root growth. Overall, dimethenamid, S-metolachlor, and oxadiazon have potential for use during bermudagrass putting green establishment, but the safety to sprigs is highly rate dependent. These herbicides may temporarily inhibit bermudagrass sprig growth, especially at high rates, but weed control from treatments could improve bermudagrass establishment relative to the untreated as reported in higher mowed bermudagrass. Further research is needed to evaluate application rates, timings, and regimens with POST herbicides to improved weed control and enhance putting green establishment.
The presence of weeds during bermudagrass (Cynodon dactylon x C. transvaalensis Burtt-Davy) putting green establishment can reduce growth and turf quality. Three field experiments were conducted in Georgia to investigate efficacy of dimethenamid, S-metolachlor, and oxadiazon on the establishment of ‘TifEagle’ bermudagrass from sprigs. From visual and digital analyses, dimethenamid at 0.85 and 1.7 kg a.i. ha-1, S-metolachlor at 1.1 and 2.2 kg a.i. ha-1, and oxadiazon at 1.1, 2.2, and 4.4 kg a.i. ha-1 did not reduce bermudagrass cover from the untreated after 12 wks. Dimethenamid at 3.4 kg ha-1 and S-metolachlor at 4.4 kg ha-1 reduced sprig cover ranging 16 to 49% from the untreated after 12 wks. All S-metolachlor and oxadiazon treatments provided excellent (=90%) green kyllinga control by 8 WAT while dimethenamid at 0.85, 1.7, and 3.4 kg ha-1 provided 78, 85, and 92% control, respectively. Dimethenamid treatments provided poor control (<70%) of spotted spurge but fair control (70 to 79%) was achieved from S-metolachlor at 4.4 kg ha-1 and oxadiazon at 2.2 and 4.4 kg ha-1 by 8 WAT. Overall, low to moderate rates of these herbicides appear to temporarily inhibit ‘TifEagle’ bermudagrass sprig establishment but high rate dimethenamid and S-metolachlor may reduce cover from the untreated.