Active Ingredient and Systemic Tubercidal Action
Sempra contains Halosulfuron Methyl, a sulfonylurea herbicide engineered as a water-dispersible granule (WG).
It works by inhibiting acetolactate synthase (ALS), an essential enzyme required for the biosynthesis of branched-chain amino acids in nutsedge plants.
Uniquely, the active chemical is absorbed through leaves and travels basipetally into underground tubers and nutlets, eliminating the reproductive reserve of Cyperus rotundus.
- Active ingredient: Halosulfuron Methyl 75 percent WG
- Tubercidal action: Eliminates underground nutsedge tubers, preventing subsequent seasonal sprouting
- Crop safety: High physiological selectivity in sugarcane and maize without inducing crop injury
Registered Crops and Optimal Application Timing
Sempra is approved for selective weed control in sugarcane and maize crops severely infested by purple and yellow nutsedge.
Application should be carried out when target nutsedge weeds are actively growing at the three to four leaf stage.
- Sugarcane: Safe for application during early cane establishment when nutsedge flushes emerge
- Maize: Applied post-emergence when corn seedlings have developed three to five true leaves
- Soil moisture: Adequate soil moisture is vital for active sap flow and rapid downward chemical translocation
Spraying Instructions and Surfactant Use
Sempra requires an approved non-ionic surfactant or adjuvant added to the spray solution to ensure droplet spreading on waxy nutsedge foliage.
Spray using knapsack equipment fitted with flat fan or floodjet nozzles for consistent, non-overlapping band coverage.
- Adjuvant addition: Mix recommended surfactant thoroughly in water before spraying
- Spray volume: Use recommended clean water volume per acre for uniform foliar wetting
- Rainfastness: Requires four hours of rain-free conditions post-application for maximum systemic absorption
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 ↗Related on KisanPe
Common questions
What weed does Dhanuka Sempra specifically control?
Sempra is specifically formulated to control purple nutsedge (Cyperus rotundus), commonly known as Motha or Lavala.
Does Sempra destroy underground nutsedge tubers?
Yes, Halosulfuron Methyl translocates downward to kill underground tubers and rhizomes, preventing new weed emergence.
Is Sempra safe for sugarcane crops?
Yes, Sempra possesses excellent crop tolerance in sugarcane when applied at label-recommended growth stages.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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