carfentrazone-ethyl (QuickSilver T&O Herbicide EPA#279-3265)
Rate When used as a stand-alone product for silvery thread moss control use 6.7 fl oz/A or 0.154 fl oz/1,000 sq ft, with a second application after 2 weeks, at the same rate. The addition of a nonionic surfactant at a rate of 0.25% v/v can increase control of silvery thread moss.
Time During daylight, apply to moss in turfgrasses listed on label. Apply when moss is actively growing for best results.
Remarks QuickSilver T&O Herbicide is a contact herbicide with little or no residual activity. It provides selective postemergence control of broadleaf weeds and silvery thread moss (Bryum argenteum) in turfgrass. It is an aryl triazolinone herbicide that interrupts chlorophyll synthesis and produces metabolic byproducts that disrupt plant cell membranes. This process occurs only in susceptible green plants in the presence of light. Symptoms may appear on foliage in 24 hr or less in susceptible plants. Complete desiccation and death occur 7 to 14 days after application. QuickSilver is rainfast within 1 hr after application. Established cool-season grasses generally tolerate applications at labeled rates. Tall fescue may yellow slightly within 3 to 5 days after application under some conditions. Recovery typically is within 4 to 7 days. If such injury cannot be tolerated, apply to a small test area before treating a large area. QuickSilver produces herbicidal symptoms only in the weed parts it contacts directly. For best results, select a spray volume and nozzle system that ensure thorough, uniform coverage, and minimize fine spray droplets. Spray droplets larger than 400 microns may reduce coverage and reduce weed control. Apply in spray volumes of 20 to 175 gal/A (0.5 to 4 gal/1,000 sq ft). Use higher spray volumes on dense weed populations, turfgrass canopies, or where uniform coverage is difficult to obtain. QuickSilver can be applied at 7 days or more after emergence to creeping bentgrass, tall fescue, perennial ryegrass, and Kentucky bluegrass.
Caution Do not apply to carpetgrass or dichondra or to lawns or turf with desirable clovers. Avoid spray drift to nontarget, desirable, susceptible plants such as vegetables, flowers, ornamentals, trees, and shrubs. Do not apply when conditions favor spray drift or poor spray coverage. Do not exceed 6.7 fl oz/A (0.1 lb ai/A) per application or 0.4 lb ai/A per season. Allow at least 2 weeks between sequential broadcast applications. Do not apply by air or through any type of irrigation system. Quicksilver can be tank-mixed with other products, but observe all label restrictions on turf tolerance of companion products. Maintain spray solution between pH 5 and pH 8.
Site of action Group 14: protoporphyrinogen oxidase inhibitor
Chemical family Triazinone