The effects of disease on insect populations

Ecological Considerations for the use of Entomopathogens in IPM

“…Steinhaus (150,151) hypothesized that tendencies to aggregate or disperse may be important to the severity or extent of disease, and that distribution of disease organisms is likely to be important in control. Delia antiqua aggregates where the habitat favors persistence and germination of Entomophthora muscae conidia, and this leads to higher disease prevalence (34).…”

Microbial Control of Insect Pests

“…However, the effect of such factors needs further substantiation. From these examples, "It can be assumed that density-dependent and density-independent mortality factors are both in volved in the totality of epizootic dynamics but there is little reason to question the generalization that disease is essentially a density-dependent mortality factor" [Steinhaus (163 )]. …”

Ii. The Importance of Environmental Factors in the Insect-Microbe Ecosystem

“…The types of relationships existing between microorganisms and insects may be arranged (Steinhaus, 1954) into a number of arbitrary categories, as follows: (a) Insects feeding on substrates previously broken down or changed by the activity of one or more microbial species; such as yeasts bringing about the fermentation of grapes in the field, thus providing optimal conditions for the developing larvae of drosophila flies. (b) Free-living microorganisms, especially bacteria and yeasts, serving directly as food for insects; 1960] e.g., mosquito and fly larvae feeding directly on bacteria in their environment.…”