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Pretilachlor (Dhanuka Craze)

Dhanuka Craze is a chloroacetamide pre-emergent herbicide for transplanted rice, containing pretilachlor 50% EC. It is the most widely used pre-emergent in Indian transplanted paddy, controlling a broad spectrum of grasses and broadleaf weeds before they emerge through the soil surface.

Composition / Active ingredient

  • Active ingredient: Pretilachlor
  • Formulation: 50% EC (emulsifiable concentrate)
  • Chemical class: Chloroacetamide
  • Common brands: Craze (Dhanuka), Rifit (Syngenta), Eraze

Mode of action

Pretilachlor inhibits very-long-chain fatty acid (VLCFA) elongase, blocking the synthesis of membrane lipids in dividing weed seedlings. Without functional cell membranes, the seedlings cannot develop and die during germination. HRAC Group 15 (VLCFA inhibitor). The molecule is absorbed mainly through the emerging shoot and coleoptile rather than the root.

The CIBRC label for Indian transplanted rice generally specifies pretilachlor formulations with the safener fenclorim to protect the rice seedling — fenclorim is a competitive substrate that enhances pretilachlor detoxification in rice while leaving the herbicide active against weeds.

Target use and dose

Standard dose is 500 ml/acre mixed in 50-60 kg sand and broadcast in 2-3 cm of standing water within 4 days of transplanting. Target weeds:

  • Grasses: Echinochloa crus-galli, E. colona, Cynodon dactylon seedlings
  • Broadleaves: Monochoria, Ammania, Ludwigia
  • Sedges: partial control of Cyperus spp.

Standing water must be maintained for 5-7 days after application to keep the herbicide active layer at the soil surface.

Safety and regulatory status

Pretilachlor binds tightly to soil colloids; leaching and groundwater risk are low. The safened formulation is selective only on rice; spray drift to broadleaf crops will cause injury. For full-season weed cover, pretilachlor at transplanting is typically followed by post-emergent ALS inhibitors such as Bispyribac Sodium Nominee Gold, Pyrazosulfuron Chempa or Novixid Penoxsulam Florpyrauxifen when escaped weeds reach 2-4 leaf stage.

See also: Bispyribac Sodium Nominee Gold, Pyrazosulfuron Chempa, Novixid Penoxsulam Florpyrauxifen, Post Emergent Paddy Herbicide Mix, Ipfencarbazone Dinkar.

References

  1. Craze — Pretilachlor 50% EC. Dhanuka Agritech.
  2. Craze Herbicide. BigHaat.