Cycloxydim: A Post-Emergence Herbicide for Grass Weed Control

Technical Introduction

Cycloxydim (IUPAC: 2-[1-(ethoxyimino)butyl]-3-hydroxy-5-(tetrahydro-2H-thiopyran-3-yl)cyclohex-2-en-1-one) is a systemic, post-emergence herbicide belonging to the cyclohexanedione (DIM) chemical class.

It acts by inhibiting acetyl-CoA carboxylase (ACCase), a key enzyme in the biosynthesis of fatty acids required for cell membrane formation. This results in the cessation of cell division in meristematic tissues of susceptible weeds, leading to growth inhibition and death.

• Mode of Action: ACCase inhibitor (HRAC Group A).

• Systemicity: Absorbed by leaves, translocated throughout the plant, especially to growing points.

• Selectivity: Effective against grasses in broadleaf crops.

Applications

• Primary Use: Post-emergence control of annual and perennial grasses.

• Crops Protected:

  • Soybean

  • Sugar beet

  • Oilseed rape (canola)

  • Potatoes

  • Sunflower

  • Vegetables (beans, peas, carrots, onions, etc.)

• Weeds Controlled:

  • Echinochloa crus-galli (barnyardgrass)

  • Setaria spp. (foxtail grasses)

  • Avena fatua (wild oats)

  • Digitaria sanguinalis (crabgrass)

  • Sorghum halepense (Johnson grass)

  • Cynodon dactylon (bermudagrass)

  • Lolium spp. (ryegrass)

Advantages

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

• Systemic Action: Moves to weed meristems for complete kill.

• Effective on Perennial Grasses: Suppresses rhizomatous species like Johnson grass.

• Post-Emergence Flexibility: Works well on both annual and perennial grasses after emergence.

• Low Crop Residue: Breaks down relatively quickly in soil, minimizing carryover risks.

Specifications (Typical Parameters)

FAQ

Q1: What is Cycloxydim mainly used for?
A: For post-emergence control of annual and perennial grass weeds in broadleaf crops such as soybeans, sugar beets, and canola.

Q2: Does Cycloxydim control broadleaf weeds?
A: No, it is specific to grasses and does not affect broadleaf weeds.

Q3: Is Cycloxydim systemic?
A: Yes, it is absorbed through leaves and translocated to meristematic tissues, ensuring complete weed kill.

Q4: Can Cycloxydim be tank-mixed with other herbicides?
A: Yes, often mixed with broadleaf herbicides to widen the weed control spectrum, but compatibility checks are necessary.

Q5: Is resistance a concern with Cycloxydim?
A: Yes, like other ACCase inhibitors (DIMs and FOPs), resistance in grasses (e.g., ryegrass, wild oats) is a growing issue. Integrated weed management is recommended.

Q6: What is the recommended application rate?
A: Generally 0.5–1.5 L/ha (depending on formulation and weed species).