Quizalofop-p-ethyl: A Selective Post-Emergence Herbicide for Grass Weed Control

Technical Introduction

Quizalofop-p-ethyl (IUPAC: ethyl (R)-2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy]propionate) is a post-emergence, selective herbicide belonging to the aryloxyphenoxypropionate (FOP) chemical group.

It is designed for selective control of annual and perennial grass weeds in broadleaf crops such as soybeans, cotton, peanuts, sugar beet, potatoes, and vegetables.

• Mode of Action: Inhibits acetyl-CoA carboxylase (ACCase), an enzyme required for fatty acid biosynthesis in grasses. This stops lipid production, leading to chlorosis and necrosis in susceptible weeds.

• Selectivity: Broadleaf crops rapidly metabolize the herbicide, ensuring crop safety.

• Systemicity: Rapidly absorbed by leaves and translocated to the growing meristems, ensuring complete kill.

Applications

• Target Crops:

  • Soybeans

  • Cotton

  • Peanuts

  • Sugar beet

  • Potato

  • Vegetables (tomato, onion, cabbage, etc.)

  • Sunflower and other dicot crops

• Weeds Controlled:

  • Annual grasses: Echinochloa crus-galli (barnyard grass), Digitaria sanguinalis (crabgrass), Setaria spp. (foxtails), Lolium spp. (ryegrass)

  • Perennial grasses: Cynodon dactylon (Bermuda grass), Sorghum halepense (Johnson grass), Agropyron repens (quackgrass)

• Timing: Applied post-emergence when weeds are actively growing, at the 2–6 leaf stage for annuals or 10–15 cm height for perennials.

Advantages

• Highly Selective: Controls grass weeds without harming broadleaf crops.

• Systemic Activity: Moves to rhizomes and stolons, effective against perennials.

• Flexible Use: Suitable across many dicotyledonous crops.

• Resistance Management: Alternative to triazine or dinitroaniline herbicides.

• Rapid Uptake: Rainfast within 1–2 hours after spraying.

Specifications (Typical Parameters)

FAQ

Q1: Which weeds are best controlled by Quizalofop-p-ethyl?
A: It is highly effective on annual grasses like barnyard grass and foxtails, and perennial grasses such as Johnson grass and Bermuda grass.

Q2: Is it safe for soybeans and cotton?
A: Yes, soybeans, cotton, peanuts, and other dicots metabolize it quickly, making it highly selective.

Q3: Does it control broadleaf weeds?
A: No, Quizalofop-p-ethyl only targets grasses. For broadleaf weeds, tank mixing with another herbicide is needed.

Q4: How quickly does it act?
A: Symptoms (leaf yellowing, wilting) appear within 5–10 days, with full control in 2–3 weeks.

Q5: Is resistance a concern?
A: Yes, some grass weeds have developed resistance to FOP herbicides. Rotating herbicide modes of action is recommended.