Chemical nature and photosystem inhibition mechanism
Paraquat Dichloride belongs to the bipyridylium chemical class and acts exclusively as a contact herbicide with zero systemic translocation.
Upon foliar absorption, it diverts electrons from Photosystem I (PSI) during photosynthetic light reactions, generating highly reactive superoxide free radicals. These radicals rupture cell membranes and cytoplasm, causing water-soaked foliage lesions and rapid desiccation within hours.
- Active ingredient: Paraquat Dichloride 24% SL (soluble liquid).
- Mode of action: Photosystem I electron diversion producing toxic reactive oxygen species.
- Rapid foliar knockdown: Visible wilting occurs within hours of sunshine exposure, leading to complete foliage burn-down.
Approved target crops and application scope
Paraquat is registered for non-selective weed suppression in commercial plantation crops, aquatic weed clearing, and potato haulm destruction.
It binds strongly and irreversibly to clay particles in the soil, leaving zero residual soil activity against emerging subsequent crops.
- Tea and Coffee plantations: Directed spraying between plantation rows to destroy tough weed mats.
- Potato haulm desiccation: Applied before harvest to destroy potato foliage, facilitating mechanical harvesting and skin curing.
- Non-crop areas: Clearing weeds along irrigation canals, bunds, and railway embankments.
- No soil residue: Rapidly inactivated upon touching soil clay minerals, preventing root uptake by succeeding crops.
Severe toxicity hazards and mandatory handling protocols
Paraquat is classified as a highly hazardous compound with severe acute toxicity upon oral ingestion, inhalation of fine mist, or dermal contact.
Strict regulatory protocols govern its sale, storage, and application, requiring specialized equipment and certified personal protective gear.
- Personal protective equipment: Wear complete chemical overalls, face shield, heavy-duty rubber gloves, and rubber boots.
- Application equipment: Utilize low-pressure knapsack sprayers with floodjet or deflector nozzles; never use mist blowers or leaking sprayers.
- Safe storage: Keep containers locked in dedicated chemical storage facilities strictly out of reach of children and domestic animals.
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
How does Paraquat herbicide destroy weeds so rapidly?
It intercepts electrons in Photosystem I, producing free radicals that break cell membranes and desiccate green foliage within hours of sunlight exposure.
Is Paraquat a selective or non-selective herbicide?
Paraquat is a completely non-selective contact herbicide that destroys any green plant tissue it contacts.
What personal safety precautions are mandatory when handling Paraquat?
Applicators must wear full-body protective gear, avoid breathing fine spray mist, use low-pressure sprayers, and store locked away.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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