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Landscape and Turf Maintenance By J.T. Brosnan and G.K. Breeden New Herbicides for 2011 A s the calendar turns each year, new herbicides are introduced into the marketplace. Many of these herbicides may benefit individuals managing cool- and warm- season turfgrass. Some of the new herbi- cides that will be available in 2011 are as follows: Specticle (active ingredient: indazi- flam) is a new preemergence herbicide from Bayer Environmental Science labeled for use on warm-season turf at rates of 2.5 to 5 oz/A. Research at the University of Tennessee has found that Specticle pro- vides effective preemergence control of crabgrass (Digitaria spp.) and annual blue- grass (Poa annua) at lower use rates than other preemergence herbicides. This herbi- cide is also labeled preemergence control of goosegrass (Eleusine indica). Individuals should use caution when ap- plying Specticle. This herbicide has a longer residual than other preemergence herbi- cides; thus, there are label restrictions per- taining to not only overseeding but establishing new warm-season turfgrass from stolons/sprigs or sod. Depending on application rate, turfgrass managers cannot overseed for 8 to 12 months after treatment with Specticle. Furthermore, the product label currently states that turfgrass managers must delay sprigging or sodding for 2 and 4 months after application, respectively. Imprelis (active ingredient: aminocy- clopyrachlor) is a new postemergence her- bicide from DuPont labeled for broadleaf weed control in cool-season turfgrasses, as well as zoysiagrass (Zoysia japonica) and cen- tipedegrass (Eremochloaophiuroides). Applica- tion rates for cool-season turfgrass range from 3 to 4.5 floz/A. On warm-season turf- grass, application rates cannot exceed 3 floz/A, mowing heights must be greater than 1/2 inch, and some temporary turf- grass injury must be tolerated. Similar to Specticle, this herbicide will provide effec- tive weed control at a lower application rate than has been used with similar chemistries 18 Landscape and Irrigation April 2011 (i.e., mixtures of 2,4-D + MCPP + dicamba). Imprelis is labeled for use on golf courses, athletic fields, sod farms, as well as residential and commercial turf. In research trials conducted at the Uni- versity of Tennessee, seedling tall fescue and perennial ryegrass have shown toler- ance to Imprelis applications for weed control. Applications of Imprelis at labeled rates have not affected perennial ryegrass or tall fescue establishment. Similarly, ap- plication of Imprelis at labeled rates 1 to 2 weeks after seeding have not been injuri- ous either. Other commonly used broadleaf weed control herbicides (e.g., mixtures of 2,4-D + MCPP + dicamba) require individuals to delay seeding for 3 to 4 weeks after application and restrict applications to newly seeded stands until the second or third mowing. Additionally, research conducted at the University of Tennessee has demonstrated that Imprelis can be tank-mixed with Ac- claim Extra (from Bayer — active ingredi- ent is fenoxaprop) to provide cool-season turfgrass managers with an option for postemergence broadleaf weed and smooth crabgrass control. SquareOne (active ingredients: carfen- trazone + quinclorac) is a new postemer- gence herbicide mixture from FMC labeled for control of certain grassy and broadleaf weeds in warm- and cool-season turfgrass as soon as 7 to 14 days after seed- ing. SquareOne is labeled for use on golf courses, athletic fields, sod farms, as well as residential and commercial turf. Applica- tion rates of SquareOne range from 8 to 18 oz/A. Celsius (active ingredients: thiencar- bazone + iodosulfuron + dicamba) is a new postemergence herbicide mixture from Bayer labeled for use on select warm-season turfgrasses at rates of 2.5 to 4.9 oz/A; however, turfgrass managers can- not exceed 7.4 oz/A in a single year. Cel- sius is not labeled for use on seashore paspalum (Paspalum vaginatum). Celsius is labeled for the control of a wide range of broadleaf and grassy weeds. Preliminary research at the University of Tennessee and the University of Georgia has also observed postemergence activity on dallisgrass (Paspalum dilatatum) follow- ing applications of Celsius in mixtures with Revolver (active ingredient foramsul- furon); however, it is not clear at this time whether these treatments will provide ef- fective, long-term control. Blindside (active ingredients: sulfentra- zone + metsulfuron) is a postemergence herbicide mixture FMC labeled for broadleaf weed control on certain cool- and warm-season turfgrasses at rates of 3.25 to 10 oz/A. Avoid applying Blindside to any cool-season turfgrasses under stress, as temporary injury can occur after appli- cation. Blindside is labeled for use on golf courses, athletic fields, sod farms, as well as residential and commercial turf. Research at the University of Tennessee has reported that applications of Blindside can increase the speed of ground ivy (Glechoma heder- acea) and Virginia buttonweed (Diodia vir- giniana) control compared to Manor (active ingredient metsulfuron) alone. Many of these herbicides will provide turfgrass managers with new options for broadleaf and grassy weed control in 2011. Always refer to the product label for specific information on proper use, tank- mixing compatibility and turfgrass tolerance. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific informa- tion and does not imply recommendation or endorsement by the University of Ten- nessee Institute of Agriculture or this pub- lication. For more information on turfgrass weed control, visit the University of Ten- nessee’s turfgrass weed science website at www.tennesseeturfgrassweeds.org. LI Dr. Jim Brosnan is assistant professor — turfgrass weed science at the University of Ten- nessee. Greg Breeden is weed science extension as- sistant at the University of Tennessee. www.landscapeirrigation.com