UNDERSTANDING AND PREVENTING INSECTICIDE RESISTANCE AND NEW R

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UNDERSTANDING AND PREVENTING INSECTICIDE
RESISTANCE AND NEW RD IN VECTOR PEST CONTROL

• BY
• DR. BILL DONAHUE
• SIERRA RESEARCH LABORATORIES

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RESISTANCE

• The ability of a significant portion of a pest
  population to survive a pesticide at rates that
  once killed most individuals of that population.
• A genetic change in response to selection.
• A natural process controlled by genetics and
  expressed in specific biochemical processes.

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TYPES OF RESISTANCE

• Metabolic changes in detoxification (enzyme)
  system within the arthropod.
• Target Site Insensitivity - receptors
• Reduced Penetration - arthropod cuticle or plant
  surfaces (leaves)
• Behavioral - avoidance

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HISTORICAL PRESPECTIVE

• 1914 San Jose Scale (insect) insensitive to
  lime sulfur
• 1946 Resistance documented in 11 species of
  arthropods
• 1947 DDT resistance first reported
• 1962 Silent Spring Environmental awareness of
  pesticides
• 1948 1983 - of arthropod species
  demonstrating resistance doubles about every 6
  years.
• 1988 504 species of arthropods are resistant to
  one or more pesticides

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REASONS FOR RESISTANCE

• High Intensity Cropping Systems Agriculture
• Food Production Animal Operations
• Disease Vector Control Programs
• Urban Pest Control Programs
• Commodity Treatments
• Routine pest control relying primarily on
  chemical control, often a single pesticide or
  class of pesticides.

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TIME UNTIL DEVELOPMENT OF RESISTANCE

• Organophosphates 14 years
• Organochlorines (DDT) 7 years
• Carbamates 5 years
• Pyrethroids 4 years
• IGRs, Bacterial Insecticides, Avermectins
• New Compounds?
• Formulations Cockroach Gel Baits, Ear Tags

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The Way It Was
DDT was hailed as the miracle insecticide and
almost perfect control product for this pest
Resistance was observed after only 5 years of use.
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Insecticide ResistanceBed Bugs

• 1930s 40s DDT insecticide of choice
• 1952-1956 DDT resistance wide spread
• 1950s Malathion insecticide of choice
• 1960-2000 Low incidence of bed bugs world wide
• 1990s Pyrethroids insecticides of choice

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Pessimist View of Resistance

• Resistance is sure to develop and there is
  nothing we can do about it!

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Optimist View of Resistance

• When you cant change the direction of the wind
  adjust you sails!

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Why Does Resistance Develop?

• Resistance is quick to develop to compounds with
  high effective kill, long residual and are highly
  selective at a single biochemical target site.
• Why? High Selection Pressure within the
  Population!

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How Can We Slow Down Resistance?

• Resistance is slow to develop with inefficient,
  short residual compounds because selection
  pressure is low!
• Select compounds that interfere with multiple
  biochemical or physiological systems.
• Mixtures like Botanical Insecticides, Synergists,
  IGRs
• Refugia A source of susceptible individuals
  (genetic) within a population Dont Kill em
  All!
• Integrated Pest Management Ecology in Action!

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INSECTICIDE RESISTANCE IN FLEAS

• 8 Species of fleas demonstrated resistance
  including cat fleas
• Low Resistance Ratios (same for German
  Cockroaches)
• High Strain Variability Relatively Isolated
  Populations
• Much Insecticide Resistance Ascribed to Cat Fleas
  may be Variation in Flea Susceptibility.

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The Modern Environmental Movement
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NEW INSECT CONTROL STRATEGY

• Reduce Reproductive Potential
• Extend Generation Time
• Early Season Treatment
• Season Long Control
• Breaking the Life Cycle
• Target most Vulnerable Life Stage
• Planned Integrated Control Methods
• Education, Knowledge Surveillance
• Least Toxic Approach Chemical, Mechanical,
  Cultural Control Techniques

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SO WHERE DO WE START?

• Pesticides must be used judiciously in an IPM
  program so as to preserve cost effective
  pesticides and maintain susceptible individuals
  in a pest population

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INTEGRATED PEST MANAGEMENT

• IPM An ecology-based control system which
  combines many techniques in an organized program
  to keep pest populations below levels of economic
  damage or nuisance.
• Control techniques are selected and applied to
  minimize risk to human health, beneficial and
  non-target organisms, and the environment.

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COMPONENTS OF AN IPM PROGRAM

• Natural Control Use or Enhance Whats There,
  Biological Control Parasites, Predators and
  Pathogens
• Cultural Control Modify Existing Practices such
  as Temperature, Watering, Fertilizing
• Mechanical/Physical Control Specialized
  Equipment or Practices Such as Mowing and Tilling
• Chemical Control Many Choices Least Toxic
  Approach!

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ELEMENTS OF AN IPM PROGRAM

• Knowledge Pest Biology and Ecology
• Integrated System of Strategies A Plan With
  Depth
• Surveillance and Monitoring Visual, Traps, Data
  Recorders
• Continuous Evaluation and Updates Is the Plan
  Working?
• Education New Information, Update the Plan

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Resistance Management - Bioassays
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Discovering New ChemistriesFrom Concept to
Reality

• Chemical Synthesis and Basic Research
• Laboratory Bioassays Multiple Tiers
• Field Testing Multiple Geographical Sites
• Toxicology Studies from Cells to the Environment
• Product Chemistry, Packaging Stability
• Regulatory EPA, States , Global/International
• Marketing Sales
• Technical Support

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Bioassay Techniques

• Dose Response - Adult Fleas on filter paper,
  nylon discs, spun glass wool, dog hair, carpet,
  sand/soil. Evaluate technical materials or
  formulations
• Topical Bioassays - Adult Fleas
• Treated Media or Substrates - Larval Fleas
• Artificial Membrane Feeding Systems - Eggs and
  Adults - Systemic or Contact Effects

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Screening New Chemistries
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Bioassay Evaluations
Residual Evaluations Test 1 1, 9, 13, 20
28 days Test 2 1, 7, 14, 28, 45, 59 91
Knockdown Evaluations _at_ 1, 2, 4, 8 24 hours
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Flea Tick Screening New Compounds
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On Farm Surveillance
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Disease
Food Poisoning Pink Eye Myiasis Bacteria,
Viruses, Protozoa Annoyance
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Ticks in the Urban Environment
Wildlife, Pets - Activities, Wooded Environments
Disease Potential, Lyme Disease
Public Perception - Monitoring
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Tick Habitats - Rural
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RESEARCH AND NEW PRODUCTS

• Repellents People, Pets Livestock,
  Environmental
• Acaricides New Compounds, Formulations, Traps
• Habitat Modification, Mapping (GIS), Models
• Field Lab Research Acarology, Epidemiology
• Basic Physiology Tick Spit - Vaccines

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Nuisance Fly Control

• House Flies, (Musca domestica) Stable Flies,
  (Stomoxys calcitrans) Little House Fly, (Fannia
  canicularis).
• Season Late Spring through Late Fall
• Pest Control Measures Truck Mounted Sprayers
  (mist blowers)
• Integrated Pest Management
• Other Measures? Light traps,
• Sticky Ribbons, Parasitic Wasps,
• Manure Management, Vacuum,
• Baits

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Results
Fly Counts from pans Visual or Volumetric
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Where Do We Go From Here?

• Identify Current Problems or Concerns
• Determine the Magnitude of the Problem
• Surveillance and Monitoring
• Develop Long Term Strategies
• Integrated Pest Management (IPM)
• Evaluate New Products
• Product Stewardship

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QUESTIONS ?
QUESTIONS ?