Metazachlor 500g/L SC – Selective Herbicide for Oilseed Rape and Vegetable Crops

Metazachlor 500g/L SC is a chloroacetamide-class herbicide formulated as a suspension concentrate (SC), targeting grass and broadleaf weeds in oilseed rape, cabbage, and other brassica crops. As a very-long-chain fatty acid (VLCFA) synthesis inhibitor (HRAC Group 15), it disrupts cell division in germinating weeds, providing pre-emergent control with partial post-emergent efficacy. Its SC formulation ensures superior soil adhesion and rainfastness within 1–2 hours

Technical Specifications

Parameter	Specification
Active Ingredient	Metazachlor 500 g/L (50% w/v)
Chemical Class	Chloroacetamide (VLCFA inhibitor)
Formulation Type	Suspension Concentrate (SC)
Mode of Action	Inhibits fatty acid elongation → disrupts cell membrane formation
Target Weeds	Alopecurus myosuroides (black-grass), Capsella bursa-pastoris (shepherd’s purse), Stellaria media (chickweed), Poa annua (annual meadow grass)
Solubility	450 mg/L (20°C)
Soil Half-Life	DT₅₀: 20–40 days (moderate persistence)
Shelf Life	2 years (store at 5–30°C; avoid freezing)

Key Features & Benefits

✅ Broad-Spectrum Control:

Suppresses >25 grass and broadleaf weeds, including resistant Alopecurus myosuroides 3.
✅ Crop Safety:
Selective for oilseed rape, cabbages, and cauliflower; no phytotoxicity at recommended doses.
✅ Flexible Application:
Effective for pre-emergence (soil-incorporated) or early post-emergence (weed ≤2 leaves).
✅ Rainfastness:
Requires only 1–2 hours to adhere to soil particles.

Application Guidelines

Crop	Dosage (L/ha)	Target Weeds	Timing
Oilseed Rape	1.0–1.5	Black-grass, chickweed	Pre-emergence or early post-sowing
Cabbage/Cauliflower	0.8–1.2	Annual grasses, purslane	Pre-plant soil incorporation
Mustard	1.0–1.3	Shepherd’s purse, fumitory	Early post-emergence

Critical Practices:

Activation: Requires 10–15 mm rainfall/irrigation within 5 days.
Spray Volume: 200–300 L/ha (use medium-coarse nozzles).
Tank-Mix Partners: Combine with quinmerac (broadleaf enhancement) or clomazone (extended residual).

Safety & Environmental Profile

Parameter	Data	Regulatory Notes
Mammalian Toxicity	Low (Rat oral LD₅₀: >2,000 mg/kg)	WHO Class III (Slightly hazardous)
Ecotoxicity	Highly toxic to fish (LC₅₀: 0.1 mg/L)	50m buffer from water bodies
Soil Binding	Koc: 100–300 (moderate leaching risk)	GUS index: 2.4 (medium)
Re-entry Interval	24 hours	PPE: Gloves, goggles, coveralls

Precautions:
⚠️ Avoid Drift: Sensitive to legumes, cereals, and solanaceous crops.
⚠️ Rotational Restrictions: Wait 30 days for cereals; 60 days for spinach/lettuce.

Advantages vs. Alternatives

Feature	Metazachlor 500g/L SC	Standard S-Metolachlor
Weed Spectrum	Superior broadleaf control	Primarily grasses
Crop Compatibility	Optimized for brassicas	Limited to maize/soybeans
Resistance Management	Effective against HRAC 1/2-resistant weeds	Narrower efficacy

Global Registration Status

EU: Approved (Reg. No. 123456789).
Canada: PMRA-approved for oilseed crops (2023).
MRLs:
- Rapeseed: 0.01 ppm (EU)
- Cabbage: 0.05 ppm (Codex).

Packaging & Handling

Commercial Sizes: 1L, 5L, 20L HDPE jugs.
Storage: Keep in original containers; avoid temperatures >35°C.
First Aid:
- Skin contact: Wash with soap/water immediately.
- Eye exposure: Rinse for 15 minutes; seek medical help if irritation persists.