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Halosulfuron-methyl (Dhanuka Sempra)

Dhanuka Sempra (Halosulfuron-methyl 75% WG) is the first sulfonylurea herbicide in India specifically targeting Cyperus rotundus (purple nutsedge) in sugarcane and maize. The technical was developed by Nissan Chemical Industry, Japan, and is marketed under licence in India by Dhanuka Agritech.

Composition / Active ingredient

  • Active ingredient: Halosulfuron-methyl
  • Formulation: 75% WG (water-dispersible granule)
  • Chemical class: Sulfonylurea

Mode of action

Halosulfuron-methyl inhibits acetolactate synthase (ALS), the first enzyme in branched-chain amino acid biosynthesis. It is classified under HRAC Group 2. The herbicide is absorbed by both leaves and roots, then translocated through xylem and phloem to underground rhizomes and nutlets (the persistent reproductive tubers of C. rotundus) — the critical feature that gives lasting control of this otherwise intractable weed. Symptoms of yellowing appear in 24-48 hours; full suppression in 7-10 days.

Target use and dose

CIBRC-registered crops are sugarcane and maize. The standard dose is 36 g/acre (about 90 g/ha) applied as a post-emergent foliar spray at the 3-5 leaf stage of nutsedge, with adequate soil moisture. Sempra also has activity on broadleaf weeds (Cyperus iria, Caesulia, Ammania) but its commercial positioning is purple nutsedge control.

Safety and regulatory status

Halosulfuron-methyl is selective only on the registered crops; spray drift onto pulses, oilseeds and cotton will cause severe injury. As an ALS inhibitor, it shares cross-resistance risk with Bispyribac Sodium Nominee Gold, Pyrazosulfuron Chempa and other Group 2 sulfonylureas; rotation with alternative MoAs such as Pretilachlor Craze (HRAC 15) is advised.

See also: Bispyribac Sodium Nominee Gold, Pyrazosulfuron Chempa, Pretilachlor Craze, Ipfencarbazone Dinkar.

References

  1. Sempra. Dhanuka Agritech.
  2. Sempra — Halosulfuron-methyl 75% WG. Cultree.