ENTOMOLOGY 135

INTRODUCTION TO BIOLOGICAL CONTROL

Interactions of Pathogens with Other Biological Control Agents

I. Polydnavirus

1. Mutualistic relationship (is it a virus?)
   1. DNA virus (is it a virus?)
   2. Braconid and ichneumonid wasps
   3. Calyx cells of wasp
2. Effect on host
3. Transmission from host to wasp

II. Microbe-associated Parthenogensis

1. Trichogrammatid species and rickettsia (Wolbachia)
2. Presence of microbes - thelyotoky (all females)
   1. Negative effect on fecundity
   2. Why? New association or other host?
3. Absence of microbes - arrhenotoky (males and females)
4. Evidence for microbe - Antibiotics to female wasps and heat treatment (>30°C for several generations)

III. Interaction between Parasites and Pathogens

1. Vector of pathogens
   1. Active
   2. Passive
2. Direct deleterious effects (Intraguild "predation" -- see below)
3. Indirect deleterious effects
4. Beneficial effects

IV. Interaction between Predators and Pathogens

1. Invertebrates
2. Vertebrates
3. Role of scavengers

V. Interactions between Pathogens

1. Synergism (including additive effects)
2. Antagonism (interference)
3. Independent coexistence

VI. Intraguild predation

1. Guild -- broadest sense to include all organisms that share a common food resources.
2. Predation -- broadest sense to include any trophic interaction between biological control agents.
3. Intraguild predation -- unidirectional or bidirectional

Selected References

• Brooks, W. M. 1973. Protozoa: host-parasite-pathogen interrelationships. Misc. Publ. Entomol. Soc. Am. 9: 105-111.
• Entwistle, P. F., P. H. W. Adams, and H. F. Evans.1977. Epizootiology of a nuclear polyhedrosis virus in European spruce sawfly (Gilpinia hercyniae): The status of birds as dispersal agents of virus during the larval season. J. Invertebr. Pathol. 29: 354-360.
• Krell, P. J.1991. Polydnaviridae. In: Atlas of Invertebrate Viruses (J. R. Adams and J.R. Bonami, eds) pages 322-338. CRC Press, Boca Raton, Florida.
• Rosenheim. J. A., H. K. Kaya, L. E. Ehler, J. J. Marois and B. A. Jaffee.1995. Intraguild predation among biological-control agents: Theory and evidence. Biol. Contr. 5: 303-335.
• Stouthamer, R. and R. F. Luck.1993. Influence of microbe-associated parthenogenesis on the fecundity of Trichogramma deion and T. pretiosum. Entomol. Exp. Appl. 67: 183-192.
• Stouthamer, R. and R. F. Luck.1993. Microbes associated with parthenogensis in wasps of the genus Trichogramma. J. Invertebr. Pathol. 61: 6-9.

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