ENTOMOLOGY 2040 SECTION XV PEST MANAGEMENT

LEARNING OBJECTIVES OF SECTION

After completing this section students should have an understanding of the following ecological processes, concepts and pest management strategies:

• The concept of economic damage.

• The different insect pest management strategies including mechanical and physical control, chemical control, biological control, and some modern alternative methods of insect control.

• The kinds of insecticides used in applied control and the different formulations of those chemicals.

• The basic differences between density dependent and density independent control.

• The biological control tools that are available including parasitoids, predators, bacteria, fungi, viruses, nematodes and protozoans.

• The components of an integrated pest management system.

Principles of Insect Pest Management.

1. What is a Pest?

2. Economic Considerations of Pest Management

        a. Equilibrium Position.

        b. Economic Threshold.

        c. Economic Injury Level.

        d. Economic Factors Considered.

3. Approaches to Pest Management

        a. Mechanical control.

            (1) Fly swatters.

            (2) Salvage Logging.

            (3) Sanitation.

            (4) Water treatment of cut logs.

        b. Kiln drying of lumber.

4. Chemical control (effects on insect and man).

        a. Pesticides: Poisons.

            (1) Characteristics.

                • Specificity - range of action.

                • Persistance - How long?

                • Toxicity - How dangerous?

                • LD 50, dose (mg/kg) lethal tol 50%.

                • Oral or dermal.

            (2) Mode of action.

                • Stomach poisons.

                • Contact Poisons.

                • Systemics.

                • Fumigants.

                • Repellents.

                • Attractants.

            (3) Insecticide chemical groups.

                • Botanicals.

                • Organochlorines (chlorinated hydrocarbons).

                • Organophosphates.

                • Carbamates.

                • Synthetic Pyrethroids.

            (4) Formulations and application.

                • Sprays.

                • Dusts.

                • Wettable powders.

                • Emusifiable concentrates (EC).

                • Ultra low volume sprays.

            (5) Pesticide safety.

                • Keep away from children.

                • Read label.

        b. Special chemical methods.

            (1) Insect growth regulators.

                • Development, J.H., Ecdysone (methoprene).

                • Cuticle formation (Diflubenzuron).

            (2) Pheromones (chemicals used within species for communication).

                • Behavioral Chemicals = semiochemicals.

                • Sex pheromones.

                • Aggregation pheromones.

                • Anti-aggregation pheromones.

                • Bark beetles (frontalin and verbenone).

            (3) Pheromones used in insect control and pest management. (Videos)

                • Detection and Monitoring.

                • Trap outs.

                • Attracticides.

                • Confusants.

5. Biological control.

        a. Action of natural enemies suppress populations.

            (1) Predators.

            (2) Parasites (parasitoids).

            (3) Pathogens.

6. Biological control.

        a. Usually Density Dependent.

        b. (Natural control - density independent).

        c. Native Biological Control Agents.

        d. Introduced Biological Control Agents.

        e. Criteria for natural enemies for introduction.

            (1) No harmful effects.

            (2) Good searching capacity, effective at various host densities.

            (3) Well-adapted to the climate, host habitat and ecology.

            (4) High host specificity.

            (5) High reproductive capacity.

        f. Predators (Examples).

        g. Parasitoids (Examples).

        h. Value of parasitoids vs. predators.

            (1) Parasitoids.

                • Generally more host specific.

                • Better adapted to hosts environment.

                • Better synchronized.

                • Lower food requirements.

                • Immature forms do not have to search for hosts.

            (2) Predators.

                • Can switch prey when hosts are rare.

                • Tend to stabilize populations.

                • Tend to be more effective in unstable environments.

        i. Pathogens.
            (1) Bacteria -- Bacillus thuringiensis (B.t. control of many species).

            (2) Fungi -- Entomophthorales spp. (Control of gypsy moth).

            (3) Viruses -- NPV ( Control of gypsy moth).

            (4) Protozoa -- Nosema (Control of fall webworm)

        j. Approaches to biological control.

            (1) Importation.

            (2) Conservation.

            (3) Enhancement.

        k. Advantages of biological control.

            (1) Control is self-perpetuating.

            (2) Control is selective and density dependent.

            (3) Does not (normally) create new problems.

        l. Disadvantages of biological control.

            (1) Not effective against "direct" pests (where any damage is unacceptable).

            (2) Some level of damage must be accepted.

            (3) Must be implemented over large areas.

            (4) May take years to become established.

7. Other Approaches to Insect Control.

        a. Host resistance. Some varieties produce better at same pest levels.

            (1) Preference/non-preference.

                • Insects tend to prefer certain plant species.

            (2) Antibiosis.

                • Host characters adversely affect pest survival.

            (3) Tolerance.

                • Plant is attacked but not damaged significantly.

        b. Legislative (legal) control. Laws to prevent entry or spread of pests.

            (1) Called "quarantines." Generally help but eventually fail.

                • Plant Quarantine Act 1912.

                    (a) Enforced within the United States by states.

                    (b). Enforced at U.S. borders by USDA.

8. Integrated Pest Management (IPM).

STUDY QUESTIONS

1. Define equilibrium position, economic threshold, and economic injury level.

2. What are the basic characteristics of commonly used insecticides?

3. What is the LD 50 of a pesticide?

4. What is the basic mode of action of the organophosphate and carbamate insecticides?

5. What are semiochemicals and how can they be used in forest pest management?

6. What is the difference between density dependent and density independent pest control?

7. Define the ideas of introduction, conservation or enhancement in relation to biological control of insects.

8. Why do you think Bacillus thuringensis used so often in control of urban pests?

9. What are the basic types of viruses used in control of insect pests?

10. Explain why biological control agents are not effective at eradicating a pest species.

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