Active ingredient and systemic mode of action
Halosulfuron methyl belongs to the sulfonylurea chemical family, delivering targeted sedge eradication.
Mode of action details:
- Active ingredient: Halosulfuron Methyl 75% WG (Water Dispersible Granules).
- Enzyme inhibition: Inhibits the acetolactate synthase (ALS) enzyme, halting the biosynthesis of essential branched-chain amino acids (valine, leucine, and isoleucine) in susceptible sedges.
- Systemic translocation: Rapidly absorbed through weed leaves and roots, moving through both xylem and phloem directly into underground basal bulbs and rhizomes.
- Selectivity: High safety margin for approved crops like sugarcane and maize when applied according to official label instructions.
Target weeds and application timing
The herbicide specifically targets challenging sedge species that resist standard weedkillers.
Application guidelines:
- Primary target weed: Purple nutsedge (Cyperus rotundus) and yellow nutsedge (Cyperus esculentus).
- Optimal spraying stage: Apply when nutsedge is actively growing and at the 3 to 5 leaf stage (height of 10 to 15 cm) with adequate soil moisture.
- Non-ionic surfactant: Typically mixed with recommended agricultural wetting agents to enhance cuticular spray penetration.
- Visible symptoms: Weed growth halts within 24 hours; foliage displays yellowing and browning within 7 to 14 days, followed by underground tuber decay.
Safe handling and sprayer cleanliness
Apply using a knapsack sprayer fitted with a flat-fan or flood-jet nozzle. Avoid spraying when rain is expected within four hours. Thoroughly flush spray tanks, hoses, and nozzles with clean water and mild detergent after application to prevent carryover injury to subsequent sensitive broadleaf crops.
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
What is the active ingredient in Sempra herbicide?
The active ingredient is Halosulfuron Methyl 75% WG, a selective sulfonylurea herbicide.
Why is Halosulfuron Methyl effective against Motha (Cyperus rotundus)?
It is systemically translocated down into underground tubers and nutlets, destroying the weed's underground reproductive nodes and preventing regrowth.
In which crops is Halosulfuron Methyl approved for use?
It is approved under CIBRC label registrations for sugarcane, maize, and specific cucurbits like bottle gourd.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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