Check the listing for details. QuickSilver T&O Herbicide - 8 Ounce. Condition: New. Listed at 199.44 USD. GENERAL INFORMATION QuickSilver T&O Herbicide is a contact herbicide with little or no residual activity that provides selective postemergence control of broadleaf weeds and silvery thread moss (Bryum argenteum) in turfgrass. The active ingredient of QuickSilver T&O Herbicide is carfentrazone-ethyl. It is an aryl triazolinone herbicide, which interrupts chlorophyll synthesis and produces metabolic byproducts that disrupt plant cell membranes. This process only occurs in susceptible green plants in the presence of light. QuickSilver T&O Herbicide rapidly penetrates into the plant cells and symptoms may be apparent on foliage of susceptible weeds in 24 hours or less. Complete desiccation and death occurs within 7 to 14 days of application. QuickSilver T&O Herbicide is rainfast within one hour after application. This product is most effective when applied to actively growing winter and summer annual seedlings. It also increases the speed of kill and expands the spectrum of control of mature and perennial broadleaf weeds (See "Weeds Controlled" section) when applied in a tank mixture with other postemergence herbicides. Extremes in environmental conditions e.g. excessively high or low moisture or temperature may affect the activity of this product. Under warm, moist conditions appearance of herbicide symptoms may be accelerated while under very dry or cool conditions the expression of herbicidal symptoms is delayed. However, this product remains highly effective under both cool and warm environmental conditions. Weeds hardened by drought and/or extremely high temperatures are less susceptible to this product and the higher rates in the range are recommended under those conditions.