Pesticides: Specialty - "Over the Top" Grass Killers

Introduction: There are a number of post-emergent grassy weed killers on the market that are labeled as “over the top” grass killers. These products can be sprayed directly “over the top” of a great number of ornamentals and will kill crabgrass, Bermuda grass and other annual and perennial grasses without damaging the ornamentals. Precautions must be taken to only use these products on and around the ornamentals listed and according to the directions on the label of each specific product. Listed below are two groups of products, both doing essentially the same thing, each group using a different chemical to obtain the same results.

Common Brand Names: (See individual products below.)

Chemical Action and Usages: (See individual products below.)

Product 1 (Fluazifop)

Common Brand Names:

Chemical Action and Usages: The above products containing the active ingredient Fluazifop-P-butyl Butyl (R)-2-4-[5-(trifluoromethyl)-2-pyridinyl]oxyphenoxypropanoate are for the control of selective annual and perennial  grassy weeds in and around ornamentals as explained in the introduction above.  The systemic chemical is translocated from the leaf blades of the grass to the roots, shoots and/or rhizomes of the plant. Initial symptoms may include cessation of growth within several days after application and yellowing or reddening of the targeted grassy weed. Complete kill may take 2-3 weeks. These products do not control broadleaf weeds or sedges. There is an extensive list of ornamental plants that these products may be sprayed “over the top.” Be sure to check the label to see if your desirable plant(s) are listed.

Cautions/Instructions Read the label carefully and apply the product according to the directions on the label. Do not mix any stronger than listed on the label. Unless already included, these products require the addition of a spray adjuvant/surfactant to achieve the desired results. Follow the strict guidelines of each product when applying to ornamentals that may be used for food after application. Do not apply where runoff may take chemical into bodies of water.    

Toxicity: In humans and domestic animals, harmful if absorbed through skin, ingested, or inhaled. May cause eye irritation.  These products are toxic to aquatic invertebrates. Slightly toxic to fish and birds. Low toxicity to bees.

Product 2 (Sethoxydim)

Common Brand Names:

Chemical Action and Usages: These products containing the active ingredient Sethoxydim: 2-[1(ethoxyimino)butyl]- 5-[2-(ethylthio)propyl]-3-hydroxy-2- cyclohexen-1-one are for control of selective annual and perennial  grassy weeds in and around ornamentals as explained in the introduction above.  The systemic chemical is translocated from the leaf blades of the grass to the roots, shoots and/or rhizomes of the plant. Growth of treated grasses stops soon after application and leaf blades may turn yellow in color. Complete kill may take 2-3 weeks. These products do not control broadleaf weeds or sedges. There is an extensive list of ornamental plants that these products may be sprayed “over the top.” Be sure to check the label to see if your desirable plant(s) are listed.

Cautions/Instructions Read the label carefully and apply the product according to the directions on the label. Do not mix any stronger than listed on the label. These products require the addition of a spray adjuvant/surfactant to achieve the desired results. Follow the strict guidelines of each product when applying to ornamentals that may be used for food after application. Do not apply directly to water or where runoff may take the chemical into bodies of water.

Toxicity: In humans and domestic animals, harmful if absorbed through skin, ingested, or inhaled. May cause substantial eye irritation.  These products are toxic to aquatic organisms. Slightly toxic to fish.  Low toxicity to birds and bees.