Mode of action and rodenticidal chemistry
- Chemical composition: Inorganic heavy-metal compound containing active zinc and phosphorus.
- Toxic mechanism: Reacts rapidly with gastric hydrochloric acid in the rodent's stomach to liberate toxic phosphine gas.
- Rapid physiological effect: Phosphine enters the bloodstream, inhibiting cytochrome oxidase and cellular respiration, resulting in mortality within hours.
- Eradicates persistent burrowing colonies across standing crops, bunds, threshing floors, and storage godowns.
Standard field baiting protocol and pre-baiting
- Pre-baiting (Days 1 and 2): Place small quantities of plain unpoisoned grain bait (cracked wheat or broken rice with vegetable oil) near active burrows to overcome natural rodent bait shyness.
- Poison baiting (Day 3): Prepare 2 percent zinc phosphide bait by mixing 1 part chemical powder with 48 parts broken grain and 1 part vegetable oil using a wooden paddle.
- Burrow closure (Day 4): Close all treated burrows with mud; burrows reopened the following morning indicate surviving rodents requiring follow-up management.
Critical safety, handling and antidote guidelines
Never touch zinc phosphide powder or baits with bare hands; always wear protective nitrile gloves and a mask. Place poison bait deep inside live burrows using a long spoon to prevent domestic livestock, birds, and pets from consuming the bait. There is no specific chemical antidote for phosphine poisoning; treatment is symptomatic, and any suspected ingestion requires immediate emergency hospitalization.
Official source
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Central Insecticides Board & Registration Committee (CIB&RC) ↗Related on KisanPe
Common questions
How does zinc phosphide eliminate field rats?
It reacts with stomach acids to release toxic phosphine gas, which stops cellular respiration and eliminates the rodent within a few hours.
Why is pre-baiting necessary before using zinc phosphide?
Rats are suspicious of new foods (bait shyness). Feeding them plain unpoisoned grain for two days builds confidence so all rodents consume the lethal dose simultaneously.
Can zinc phosphide bait be touched with bare hands?
No, always handle zinc phosphide and prepared baits with gloves and wooden spoons to protect human skin and prevent human scent on the bait, which repels rats.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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