III. Lipid synthesis inhibitors (SOA 1)
The lipid inhibitors include these herbicide families:
- Cyclohexanedione
- Aryloxyphenoxypropionate
- Phenylpyrazolin
These herbicides prevent the formation of fatty acids, components essential to produce plant lipids.
Lipids are vital to the integrity of cell membranes and new plant growth. The lipid inhibitor herbicides inhibit a single key enzyme, acetyl-CoA carboxylase, involved in fatty acid biosynthesis.
Broadleaf plants are tolerant to these herbicide families, but almost all perennial and annual grasses are susceptible.
These herbicides are foliar-applied and move in the phloem to areas of new growth. Injury symptoms are slow to develop (seven to 10 days) and appear first on new leaves emerging from the whorl of the grass plant. Plants gradually will turn purple and brown, and die, but older leaves may stay green for a long time.
These herbicides are short-lived in the soil, have a low water solubility and are used at relatively low rates. They have a low leaching potential.
Application of the postemergence grass herbicides tank-mixed with a broadleaf herbicide often results in reduced grass control, a response called antagonism. The antagonism can be overcome by applying the separate herbicides several days apart or by increasing the rate of the grass-control herbicide in the tank mix.
Herbicide use
- Clethodim (Select, Select Max) for alfalfa, canola, chickpea, dry bean, field pea, flax, lentil, tame mustard, potato, soybean, sugar beet and sunflower.
- Sethoxydim (Poast) for alfalfa, canola, chickpea, dry bean, field pea, flax, lentil, tame mustard, potato, soybean, sugarbeet and sunflower.
Injury symptoms
Sugarbeet is not injured by cyclohexanediones, even at high rates.
Site of action
Acetyl-CoA carboxylase enzyme.
Herbicide use
- Clodinafop-P (Discover NG) for wheat.
- Fenoxaprop-P (Puma) for barley and wheat.
- Fluazifop-P (Fusilade DX) for soybean and sugarbeet.
- Quizalofop (Assure II) for canola, chickpea, dry bean, field pea, flax, lentil, soybean, sugarbeet and sunflower.
Injury symptoms
Sugarbeet is not injured by aryloxyphenoxypropionates used alone but would be injured by mixtures with other herbicides such as in Wolverine Advanced.
Site of action
Acetyl-CoA carboxylase enzyme.
Herbicide use
Pinoxaden (Axial XL) for barley and wheat.
Injury symptoms
Sugarbeet is not injured by phenylpyrazolin used alone but would be injured by mixture with other herbicides such as Axial Star.
Site of action
Acetyl-CoA carboxylase enzyme.
CAUTION: Mention of a pesticide or use of a pesticide label is for educational purposes only. Always follow the pesticide label directions attached to the pesticide container you are using. Be sure that the area you wish to treat is listed on the label of the pesticide you intend to use. Remember, the label is the law.
Reviewed in 2018