Importance of Beneficial Insects in Agriculture

Beneficial insects are species that provide essential services like pollination, pest control, weed management, and soil enhancement in agricultural ecosystems. They play a vital role in maintaining ecological balance, improving crop yield, and reducing the need for chemical inputs.

1. Importance of Beneficial Insects

• Pollination and Pest Control: Beneficial insects assist in pollination and natural pest control, contributing to crop productivity.
• Environmental Impact: Encouraging beneficial insects is a key strategy in organic farming, reducing the need for chemical pesticides and minimizing environmental pollution.
• Soil Health: Certain insects contribute to soil aeration and nutrient cycling, enhancing soil fertility.
• Economic Benefits: By enhancing pollination and reducing pest-related losses, beneficial insects contribute to increased agricultural productivity and economic gain.

2. Categories of Beneficial Insects

1. Pollinators: Insects that transfer pollen from the male anthers to the female stigma of flowers, aiding fertilization and fruit development.
2. Natural Enemies: Predators and parasitoids that feed on agricultural pests.
3. Weed Killers: Insects that feed on invasive weeds, contributing to natural weed control.
4. Soil Builders: Insects that improve soil structure and nutrient cycling.

2.1. Pollinators

Pollinators play a crucial role in the reproduction of flowering plants, including many crops. Around 35% of global food production depends on pollinators.

• Examples:
  • Honeybees (Apis mellifera): Major pollinators for a variety of crops.
  • Bumblebees (Bombus spp.): Effective pollinators for crops like tomatoes and cranberries.
  • Butterflies and Moths (Lepidoptera): Pollinate a wide range of flowering plants.
  • Beetles (Coleoptera) and Flies (Diptera): Pollinate crops like carrots, mustards, and almonds.
  • Weevil (Elaeidobius kamerunicus): Pollinates oil palm.

2.2. Natural Enemies

Natural enemies include predators and parasitoids that regulate pest populations through natural biological control.

• Predators: Insects that consume multiple prey during their lifetime. Example: Lady Beetles (Coccinellidae) that feed on aphids.
• Parasitoids: Insects whose larvae develop inside a host, eventually killing it. Example: Parasitic Wasps (Braconidae) that target caterpillars.

2.3. Weed Killers

Certain insects feed on invasive weeds, contributing to natural weed management.

• Examples:
  • Leaf Beetle (Octotoma scabripennis) and Leaf-mining Chrysomelids (Uroplata gualdi) control Lantana camara.
  • Zygogramma bicolorata targets Parthenium (Congress weed).
  • Neochetina spp. are biocontrol agents for water hyacinth.

2.4. Soil Builders

Soil builders improve soil structure and nutrient cycling by creating channels for air and water.

• Examples:
  • Dung Beetles (Scarabaeidae): Enhance nutrient recycling by burying dung.
  • Ants and Termites: Improve soil aeration and nutrient availability.
  • Larvae of Flies, Crickets, and Wasps: Contribute to soil fertility.

3. Productive Insects in Agriculture

3.1. Honeybee (Apis spp.)

• Role: Pollination, honey production, and production of beeswax, royal jelly, pollen, and bee venom.
• Economic Importance: Enhances crop productivity through pollination. Honey and beeswax have significant market value.
• Species in India:
  • Apis dorsata (Rock bee) – High honey yield.
  • Apis cerana indica (Indian bee) – Domesticated for honey production.
  • Apis mellifera (European bee) – Widely used in commercial beekeeping.
  • Apis florea (Little bee) – Low honey yield but important for pollination.

3.2. Silkworm (Bombyx mori)

• Role: Produces silk through the secretion of fibroin protein from silk glands.
• Economic Importance: Forms the basis of the sericulture industry, supporting rural livelihoods.
• Types of Silkworms:
  • Mulberry Silkworm (Bombyx mori) – Feeds on mulberry leaves, producing high-quality silk.
  • Tasar Silkworm (Antheraea mylitta) – Wild silk variety, feeds on oak leaves.
  • Eri Silkworm (Samia cynthia ricini) – Feeds on castor leaves, producing eri silk.
  • Muga Silkworm (Antheraea assamensis) – Native to Assam, produces golden silk.

3.3. Lac Insects (Kerria lacca)

• Role: Produces lac, a resinous secretion used to make shellac, varnish, and dyes.
• Economic Importance: Supports rural income through lac cultivation.
• Host Plants: Kusum, Palas, and Ber trees.
• Applications: Used in food processing, pharmaceuticals, and the cosmetic industry.

4. Bioagents as Natural Enemies

Bioagents are living organisms used for biological pest control. They help reduce pest populations naturally, minimizing chemical pesticide use.

• Types of Bioagents:
  • Predators: Consume multiple prey. Example: Lady Beetles (Coccinellidae).
  • Parasitoids: Lay eggs on or inside host pests. Example: Trichogramma spp.
  • Pathogens: Infect and kill pests. Example: Bacillus thuringiensis (Bt).

5. Institutes Related to Beneficial Insects in India

1. National Bureau of Agricultural Insect Resources (NBAIR), Bangalore Focus: Collection, characterization, documentation, and conservation of agriculturally important insect resources.
2. Project Directorate of Biological Control (PDBC), Bangalore Focus: National-level biological control research.
3. National Centre for Integrated Pest Management (NCIPM), New Delhi Focus: Promoting environmentally sound Integrated Pest Management (IPM) technologies.
4. Khadi & Village Industries Commission (KVIC), Mumbai Focus: Development of the beekeeping industry and training in modern apiculture.
5. Central Bee Research & Training Institute, Pune Focus: Research and training in beekeeping practices.
6. All India Coordinated Research Project on Biological Control (AICRP-BC&W) Focus: Biological control of crop pests and weeds under ICAR.