Clodinafop-Propargyl: A Selective Post-Emergence Herbicide for Grass Weed Control

Technical Introduction

Clodinafop-propargyl (IUPAC: (R)-2-[4-(5-chloro-3-fluoro-2-pyridyloxy)phenoxy]propionic acid prop-2-ynyl ester) is a post-emergence, selective systemic herbicide belonging to the aryloxyphenoxypropionate (FOP) group.

It is primarily used to control annual grass weeds in wheat and barley fields, without damaging the crops themselves.

• Mode of Action: Inhibits the enzyme acetyl-CoA carboxylase (ACCase), which is essential for fatty acid biosynthesis in grasses. This disrupts cell membrane formation and kills susceptible grass weeds.

• Selectivity: Kills grass weeds but is safe on broadleaf crops like wheat due to crop metabolism.

• Systemicity: Absorbed by leaves, translocated to growing points.

Applications

• Target Crops:

  • Wheat (main use)

  • Barley

• Weeds Controlled:

  • Phalaris minor (littleseed canary grass)

  • Avena fatua (wild oats)

  • Lolium rigidum (ryegrass)

  • Setaria spp.

  • Echinochloa crus-galli (barnyard grass, partial control)

• Usage Timing:

  • Applied post-emergence when weeds are at 2–4 leaf stage and the crop is well established.

Advantages

• Highly Selective: Effective on grass weeds without harming wheat.

• Post-Emergence Application: Controls weeds after they have emerged, giving flexibility in weed management.

• Low Application Rate: Highly active at low dosages.

• Systemic Movement: Moves to the meristematic tissue, ensuring complete weed kill.

• Alternative to Isoproturon: Very effective against isoproturon-resistant Phalaris minor in wheat.

Specifications (Typical Parameters)

FAQ

Q1: Which weeds are best controlled by Clodinafop-propargyl?
A: It is most effective against Phalaris minor, wild oats, and ryegrass in wheat crops.

Q2: Is it safe for broadleaf crops?
A: Yes, wheat and barley are tolerant due to rapid herbicide metabolism. However, it should not be used in oat crops, which are sensitive.

Q3: When should it be applied?
A: Apply post-emergence when weeds are at the 2–4 leaf stage for best results.

Q4: Can Clodinafop control broadleaf weeds?
A: No, it is specific to grass weeds. A tank mix with a broadleaf herbicide is often recommended.

Q5: Is there resistance to Clodinafop?
A: Yes, some grass weeds have developed resistance to ACCase inhibitors. Resistance management strategies (herbicide rotation, integrated weed management) are advised.