ENTOMOLOGY 135

INTRODUCTION TO BIOLOGICAL CONTROL

Microbial Control

Entomology 135

I. Introduction

1. Parasitoids and predators
2. Pathogens
3. Chemical pesticides
4. Basic premise - not level of control desired; may use same agent or different agent

II. Microbial control approaches

1. Short-term control (temporary or inundative) - used as an insecticide
2. Long-term control (permanent or inoculative) - classical BC approach or season long approach
   • like Cryptolaemus
3. Integrated control
   1. Compatibility with chemical pesticides
   2. Habitat modification
4. Novel methods
   1. Disruption of symbionts
   2. Activation of chronic or latent infection
5. Biotechnology (to be discussed later)

III. Principles of microbial control

1. Timing
   1. Target pest
   2. Moist vs dry
   3. Evening vs morning
2. Coverage
3. Application technology
   1. Sprayers (hand to aerial)
   2. Dusters
   3. "Microgation" (Chemigation concept)
   4. Introduction of diseased or contaminated insects
      1. Pathogen in first
      2. Pathogen after
   5. Autodissemination (misnomer)
4. Manipulation of environment
5. Formulations (art vs science)
   1. Dust
   2. Baits
   3. Wettable powder
   4. Liquid
   5. Emulsifiable
   6. Additives (feeding stimulant, stickers, wetting agents, etc.)
   7. Others (sawdust, clay-coating, encapsulation, etc.)

IV. Some microbial control agents registered with EPA (Some commercially available)

1. Bt subsp. kurstaki
   1. Insecticidal protein vs. Bt toxin
   2. Target insects (Types I to IV)
   3. Use patterns (agriculture vs. forestry)
   4. No tolerance level
   5. Concept of international units (IU)
   6. Genetically-engineered Bt toxin in Pseudomonas fluorescens
2. Bt subsp. israelensis
   1. Culex and Aedes susceptible
   2. Anopheles less susceptible
   3. Aedes aegypti units
3. Bt subsp. tenebrionis
   1. Colorado potato beetle
   2. Elm leaf beetle
4. Bt subsp. aizawai
5. Bacillus popilliae and B. lentimorbus
   1. Production
   2. Use patterns (eradication vs. suppression)
6. Hirsutella thompsonii
   1. Citrus rust mite
   2. Use pattern
   3. Problems
7. Verticillium lecanii (Europe only)
   1. Aphids and whiteflies
   2. Use patterns
8. Lagenidium giganteum (Mosquitoes)
9. Metarhizium anisopliae (Cockroaches)
10. Nosema locustae
    1. Production
    2. Grasshoppers and Mormon crickets
    3. Use patterns
11. Gypsy moth NPV
12. Orygia NPV (Douglas-fir tussock moth)
13. Neodiprion NPV (European pine sawfly)
14. Heliothis NPV
    1. Production
    2. Use patterns
    3. Field problems
    4. Acceptance problems
    5. Field trials in Mississippi
15. Romanomermis culicivorax
    1. No registration with EPA
    2. Production
    3. Problems
16. Heterorhabditis and Steinernema
    1. No registration with EPA
    2. Production
    3. Use patterns
    4. Problems

V. Other Pathogens

1. Bacillus sphaericus
   1. Target insects - Anopheles
   2. Use patterns
2. Bt strains other than those commercialized
3. Serratia entomophila
   1. New Zealand -- registered
   2. White grubs -- Amber disease
   3. Slow death; stop feeding
4. Beauveria bassiana
5. Autographa NPV
6. Spodoptera NPV
7. Codling moth granulosis virus (GV)
   1. Target insects
   2. Use patterns
   3. UC as registrant
   4. Role of IR-4 program
   5. Registered in West Germany and Switzerland
8. Indianmeal moth GV
9. Western grapeleaf skeletonizer GV
   1. Colony feeder
   2. Midgut infection
   3. Transovum transmission
   4. Persistent
10. Entomopoxvirus of grasshoppers

VI. Commercialization of microbial control agent

1. Isolation, identification, and characterization
2. Laboratory efficacy against target insects (Koch's Postulates)
3. Evaluation for small scale production
4. Patent organism and/or process
5. Safety tests (Tier 1 testing) - Environmental risk assessment
   1. Effect on humans and other vertebrates
   2. Other nontarget organisms
      1. Btk and Monarch butterfly
      2. Toxin production
6. Develop Quality Control (QC)
7. Evaluate A to E to determine commercial feasibility (cost, packaging, safety, formulations, etc.)
8. Small field tests (under 10 acres - need Experimental Use Permit (EUP))
9. Evaluate effect on nontarget organisms (laboratory and field)
10. Evaluate feasibility of commercialization
11. Large scale field tests for efficacy (EUP in different states)
12. EPA approval - Commercial production (marketing, sales, etc.)
13. Cottage industry vs. large corporations

VII. Commercial interests in microorganisms

1. Search for metabolites with insecticide (or other) activity
2. Utilize as expression vector (to be covered later)

VIII. Advantages of microbial control (see handout)

IX. Disadvantages of microbial control (see handout)

Selected References

• Burges, H. D. (ed)1981. Microbial Control of Pests and Plant Diseases 1970-1980. Academic Press, New York. 949 pp.
• Kurstak, E. (ed)1982. Microbial and Viral Pesticides. Marcel Dekker, Inc. New York. 720 pp.
• Tanada, Y. and H. K. Kaya.1993. Insect Pathology. Academic Press, San Diego. 666 pp. Chapter 15

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