Insects and People: Insect Pest Management

  • It is vital to keep the bad insects at a population density below the economic injury level (EIL)

Nonchemical Methods

  • Physical Control: Manipulate pest’s environment
    • Temperature: roast them and freeze them
    • Atmosphere: eliminate oxygen
    • Sound: not sure if it works
  • Mechanical Control: using a mechanical device
    • Swat them, squash them, or pick them off
    • Exclusion devices: keep them out
    • Traps: fry them or stick them
  • Cultural Control: manipulating standard farm practices
    • Plow them under or turn them up
    • Crop manipulation
    • Host resistance; plant breeders and entomologists
  • Biological Control: the use of natural enemies to reduce insect populations below EIL
    • Requires deliberate human intervention
    • Must not eradicate the pest
  1. Pathogens: viruses, bacteria, protozoans, fungi, nematodes

   

  1. Cause disease in insects; germ warfare
  2. Can be applied like the chemical insecticides
  3. Bacillus thuringiensis (Bt) most widely used
    1. Predators: free living animal that feeds on other animals (prey)

   

  1. Coleoptera
  2. Heteroptera, Hymenoptera, Diptera
  3. Birds and fish used occasionally
    1. Parasitoids: kills its insect host by living on or inside the host

   

  1. Many tiny wasps (Hymenoptera)- most common
  2. Flies (Diptera) and a few other groups
    1. Three main approaches to biological control

   

  1. Conservation of natural resources already present

       1. careful use of insecticides 2. Adding nesting sites, alternate hosts

  1. Augmentation of natural enemies already present

       1. Rear and release more natural enemies 2. Lady beetles, lacewings, wasps, pathogens

  1. Importation and establishment of natural enemies to control exotic pests

       1. Premise: introduction of foreign pests without natural enemies 2. Go to pest’s native country and find natural enemies

History and Use of Chemical Pesticides

  • Pesticide: agent/chemical to kill pests (weed, insect, fungus, rodent, etc)
  • Insecticide: agent/chemical used to kill insects
    • Recorded use dates back over 3,000 years
    • Synthetics only 50+ years old
  • Over 1.25 billion lbs of pesticides are produced in the U.S. each year (440 M lbs insecticides)
  • Almost $12 billion in U.S. retail sales
    • 68% herbicides, 21% insecticides, 8% fungicides, 3% others
    • 82% used in agriculture, only about 7% in homes
  • Over 400 insecticides registered with the EPA for thousands of uses

Target Sites/Modes of Action

  • Exoskeleton or cuticle poisons
    • Abrasion and/or absorption of wax
    • Disruption of chitin synthesis/degradation
  • Respiratory poisons
    • Fill up tracheal tubes
    • Fumigate with toxic gases
  • Stomach poisons
    • Must be eaten to be toxic
    • Many older chemicals; general poisons
  • Hormone mimics
  • Nerve poisons
    • Most modern synthetic organic insecticides
    • Readily penetrate cuticle; contact poisons
    • Disrupt the transmission of nerve signals
  • Plants with built-in insecticides
    • Many naturally occurring insecticides
    • Biotechnology and Bt plants