UNDERSTANDING AND PREVENTING INSECTICIDE RESISTANCE AND NEW RD

UNDERSTANDING AND PREVENTING INSECTICIDE RESISTANCE AND NEW R&D IN VECTOR PEST CONTROL BY: DR. BILL DONAHUE SIERRA RESEARCH LABORATORIES

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

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

HISTORICAL PRESPECTIVE n n n 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

REASONS FOR RESISTANCE n n n 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.

TIME UNTIL DEVELOPMENT OF RESISTANCE Organophosphates – 14 years n Organochlorines (DDT) – 7 years n Carbamates – 5 years n Pyrethroids – 4 years n IGR’s, Bacterial Insecticides, Avermectins n New Compounds? n Formulations – Cockroach Gel Baits, Ear Tags n

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.

Insecticide Resistance Bed Bugs 1930’s – 40’s: DDT insecticide of choice n 1952 -1956 DDT resistance wide spread n 1950’s: Malathion insecticide of choice n 1960 -2000: Low incidence of bed bugs world n wide n 1990’s: Pyrethroids insecticides of choice

Pessimist View of Resistance is sure to develop and there is nothing we can do about it!

Optimist View of Resistance When you can’t change the direction of the wind – adjust you sails!

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

How Can We Slow Down Resistance? n n n 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, IGR’s Refugia – A source of susceptible individuals (genetic) within a population – Don’t Kill ‘em All! Integrated Pest Management – Ecology in Action!

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

The Modern Environmental Movement

NEW INSECT CONTROL STRATEGY n n n n n 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

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

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.

COMPONENTS OF AN IPM PROGRAM n Natural Control – Use or Enhance What’s There, Biological Control – Parasites, Predators and Pathogens n Cultural Control – Modify Existing Practices such as Temperature, Watering, Fertilizing n Mechanical/Physical Control – Specialized Equipment or Practices Such as Mowing and Tilling n Chemical Control – Many Choices – Least Toxic Approach!

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

Resistance Management - Bioassays

Discovering New Chemistries From Concept to Reality Chemical Synthesis and Basic Research n Laboratory Bioassays – Multiple Tiers n Field Testing – Multiple Geographical Sites n Toxicology Studies from Cells to the Environment n Product Chemistry, Packaging & Stability n Regulatory – EPA, States , Global/International n Marketing & Sales n Technical Support n

Bioassay Techniques n n 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

Screening New Chemistries

Bioassay Evaluations Knockdown Evaluations @ 1, 2, 4, 8 & 24 hours Residual Evaluations Test #1 1, 9, 13, 20 & 28 days Test #2 1, 7, 14, 28, 45, 59 & 91

Flea & Tick Screening New Compounds

On Farm Surveillance

Disease Food Poisoning Pink Eye Myiasis Bacteria, Viruses, Protozoa Annoyance

Ticks in the Urban Environment Wildlife, Pets - Activities, Wooded Environments Disease Potential, Lyme Disease Public Perception - Monitoring

Tick Habitats - Rural

RESEARCH AND NEW PRODUCTS n Repellents – People, Pets & Livestock, Environmental n Acaricides – New Compounds, Formulations, Traps n Habitat Modification, Mapping (GIS), Models n Field & Lab Research – Acarology, Epidemiology n Basic Physiology – “Tick Spit” - Vaccines

Nuisance Fly Control n n n 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 n Other Measures? Light traps, Sticky Ribbons, Parasitic Wasps, Manure Management, Vacuum, Baits n

Results Fly Counts from pans – Visual or Volumetric

Where Do We Go From Here? Identify Current Problems or Concerns n Determine the Magnitude of the Problem n Surveillance and Monitoring n Develop Long Term Strategies n Integrated Pest Management (IPM) n Evaluate New Products n Product Stewardship n

QUESTIONS ?