Pesticides_and_Indian_Agriculture_a_Revi

Pesticides and Indian Agriculture - A Review

Introduction

  • Pesticides are substances (natural or manmade) used to control:

    • Pests

    • Weeds

    • Diseases in plants in various agronomic practices.

  • Common types of pesticides include:

    • Herbicides

    • Insecticides

    • Fungicides

  • Crop losses due to pests are significant:

    • Wheat losses: 10%-28%

    • Rice losses: 25%-41%

    • Maize losses: 20%-41%

    • Potato losses: 8%-21%

    • Soybean losses: 11%-32%.

  • The use of pesticides has increased significantly, but crop losses remain unchanged over last 40 years.

  • Increase in farming demand due to population growth forecasted to raise food production demand by 70%.

Pesticide Classifications

Classification by Toxicity

  • Toxicity is determined by dose and time (exposure).

  • Categories based on LD50:

    • Class Ia: Extremely Hazardous (LD50 < 5 mg/kg)

    • Class Ib: Highly Hazardous (LD50: 5-50 mg/kg)

    • Class II: Moderately Hazardous (LD50: 50-2000 mg/kg)

    • Class III: Slightly Hazardous (LD50: > 2000 mg/kg)

    • Class V: Unlikely to present acute hazard (LD50: 5000+ mg/kg)

Classification by Chemical Composition

  • Chemical classification includes:

    • Insecticides:

      • Examples: Carbamates (Carbaryl), Organophosphorus (Monocrotophos)

    • Fungicides:

      • Examples: Aliphatic nitrogen fungicides (dodine)

    • Herbicides:

      • Examples: Anilide herbicides (blufenacet)

    • Rodenticides:

      • Inorganic (Zinc phosphide) & organic (bromadiolone)

Classification by Pest Functionality

  • Different types based on their functionality include:

    • Insecticides: Kill insects

    • Fungicides: Kill fungi

    • Herbicides: Kill unwanted plants

    • Bactericides: Kill bacteria

    • Virucides: Kill viruses

Classification by Mode of Entry

  • Systemic: Absorbed by plants, e.g., Glyphosate

  • Contact (non-systemic): Affects through contact, e.g., Paraquat

  • Stomach poisons: Ingested toxins, e.g., Malathion

  • Fumigants: Vapors that kill pests through inhalation.

Pesticide Usage in India

  • India has 293 pesticides registered, with 104 still produced despite prohibition elsewhere.

  • Major focus on cotton pest management (50% of insecticides).

  • Average pesticide application in India is low (0.31 kg per ha), compared to other countries.

  • Pesticide consumption in India rose from 5,000 MT (1958) to 57,000 MT (2016-17).

  • Current statistics:

    • Insecticides: Most widely used

    • Fungicides: Sulphur is frequently used

    • Herbicides: High concentration of 2,4-D amine salts.

Biopesticide Usage

  • Bio-pesticides comprise a minor (9%) part of overall pesticide consumption.

  • Notable biopesticides in India include Neem extracts and Bacillus thuringiensis (Bt).

  • Increasing demand for organic alternatives due to health and environmental concerns.

Discussion on Environmental Impact

  • Indiscriminate pesticide use leads to pollution and harm to non-target species, causing health issues in agriculture.

  • Chemical pesticide residues in crops raise concerns for safe food production.

Conclusion

  • For over 60 years, pesticides have helped boost agriculture but require careful management due to environmental and health impacts.

  • A shift towards bio-pesticides is encouraged for sustainable practices in Indian agriculture.

  • Collaboration between commercial and public sectors is needed to support sustainable practices.