Organophosphate

1. Organophosphate Group of
Insecticides
• Presented by: [Your Name]
• Course/Seminar: [Subject Title]
• Institution: [Your College/University]

2. Introduction to Organophosphates
• Synthetic insecticides derived from phosphoric
acid esters.
• Developed post-WWII as alternatives to
organochlorines like DDT.
• Broad-spectrum: effective against sucking,
chewing, and soil insects.
• Act as contact, systemic, and stomach poisons.
• Rapidly degrade; less persistent but highly

3. Chemical Nature & Properties
• Esters, amides, or thiol derivatives of
phosphoric acid.
• Oily liquids, soluble in organic solvents.
• Degrade quickly in alkaline pH.
• Formulations: EC, G, SP, WP.
• Moderate residual activity (3–15 days).

4. Mode of Action
• Target: insect nervous system.
• Inhibit enzyme acetylcholinesterase (AChE).
• Leads to acetylcholine accumulation at nerve
synapses.
• Causes continuous nerve stimulation →
paralysis → death.
• IRAC Group 1B – Acetylcholinesterase
inhibitors.

5. Common Organophosphates – I
• Chlorpyrifos (Dursban/Lorsban) – 20EC/50EC,
2–2.5 ml/L: termites, stem borer.
• Dimethoate (Rogor/Tafgor) – 30EC, 1–2 ml/L:
aphids, jassids.
• Malathion (Cythion) – 50EC, 1.5–2 ml/L: mites,
thrips.
• Quinalphos (Ekalux) – 25EC, 1.5–2 ml/L: fruit
borer, leaf folder.

6. Common Organophosphates – II
• Monocrotophos (Monocil/Nuvacron) – 36SL,
1–1.5 ml/L: bollworms.
• Phorate (Thimet) – 10G/5G, 10–15 kg/ha: root
grubs, stem borer.
• Methyl Parathion (Folidol) – 50EC, 0.75–1
ml/L: leafhoppers.
• Ethion (Ethios) – 50EC, 1.5–2 ml/L: mites,
hoppers.

7. Major Crops & Diseases Controlled
• Paddy – stem borer, leaf folder (Chlorpyrifos,
Quinalphos).
• Cotton – aphids, bollworms (Dimethoate,
Monocrotophos).
• Vegetables – thrips, fruit borer (Malathion,
Acephate).
• Fruits – hoppers, mites (Ethion, Diazinon).
• Sugarcane – root grub, shoot borer (Phorate,

8. Dosage & Application Guidelines
• Apply at recommended dosage to avoid
phytotoxicity.
• Do not mix with alkaline materials.
• Use protective clothing during spraying.
• Avoid spraying during strong winds or midday
heat.
• Maintain pre-harvest interval (10–21 days).

9. Toxicity & Safety
• Toxic class I–II: high to moderate toxicity.
• Routes: skin, inhalation, ingestion.
• Symptoms: headache, nausea, salivation,
breathing issues.
• Antidote: Atropine sulfate + Pralidoxime (2-
PAM).
• Toxic to bees, fish, and birds; avoid
contamination.

10. Advantages
• Broad-spectrum and quick-acting.
• Effective on resistant pests.
• Some are systemic (Dimethoate,
Monocrotophos).
• Useful for foliar and soil pest management.

11. Limitations
• Highly toxic to humans and environment.
• Pests develop resistance with continuous use.
• Kills beneficial insects and pollinators.
• Short residual period; frequent applications
required.
• Some compounds banned or restricted.

12. Summary
• Group: Organophosphorus insecticides.
• Mode of Action: AChE inhibition leading to
nervous paralysis.
• Key examples: Chlorpyrifos, Dimethoate,
Malathion, Quinalphos, Monocrotophos.
• Broad-spectrum control in major crops.
• Follow safety and IPM guidelines.

13. References
• CIBRC (Central Insecticide Board &
Registration Committee, India).
• IRAC MoA Classification (Group 1B).
• FAO & WHO Pesticide Data Sheets.
• Textbooks: Plant Protection Chemicals,
Insecticide Toxicology.