Chemical profile and systemic mode of action
Halosulfuron Methyl targets the specific enzyme responsible for branched-chain amino acid synthesis.
- Chemical Group: Sulfonylurea (IRAC/HRAC Group 2 - ALS/AHAS inhibitor).
- Enzyme Inhibition: Blocks acetolactate synthase (ALS), preventing the synthesis of essential amino acids (valine, leucine, isoleucine).
- Complete Tuber Translocation: Absorbed through nutsedge leaves and rapidly translocated downward into the basal bulbs, rhizomes, and underground nut tubers.
- Permanent Eradication: Halts cell division in nutsedge shoots and underground tubers, causing systemic yellowing and complete collapse.
Target crops and application timing
Timing application to active nutsedge vegetative growth ensures thorough translocation into tubers.
- Approved Crops: Sugarcane and Maize under CIBRC label directives.
- Target Weeds: Purple nutsedge (Cyperus rotundus) and broadleaf sedges.
- Application Window: Apply post-emergence when nutsedge plants are actively growing and at the 3 to 5 leaf stage.
- Soil Moisture: Adequate soil moisture is essential at the time of application to facilitate systemic translocation.
- Rainfastness: Requires 2 to 4 hours of rain-free weather following spraying for complete foliar uptake.
Spraying best practices and equipment care
Using non-ionic surfactants and dedicated nozzles ensures uniform leaf deposition.
- Add a recommended non-ionic surfactant to the spray tank to improve wetting and penetration on waxy nutsedge foliage.
- Use a knapsack sprayer fitted with a flat fan or flood jet nozzle for uniform swath distribution.
- Do not disturb or cultivate the soil for 10 to 14 days after spraying to allow the active chemical to translocate fully into underground tubers.
- Strictly follow the pre-harvest interval (PHI) and crop safety instructions printed on the product packaging.
Official source
Check the latest rules, benefits and forms here. KisanPe is an independent platform and is not a government website.
Central Insecticides Board & Registration Committee (CIBRC) ↗Related on KisanPe
Common questions
How does Halosulfuron Methyl destroy purple nutsedge tubers?
It is absorbed by nutsedge leaves and translocated downward through the vascular system into underground bulbs and tubers, blocking cell division and rotting the root network.
Can Halosulfuron Methyl 75 WG be sprayed in sugarcane?
Yes, Halosulfuron Methyl 75% WG is officially registered and approved for selective post-emergence nutsedge control in sugarcane fields.
How long after spraying should the field remain undisturbed?
Leave the field un-hoed and un-cultivated for at least 10 to 14 days after spraying so the herbicide translocates thoroughly into all interconnected underground tubers.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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