ENTOMOLOGY 135 1995 Final

ENTOMOLOGY 135

INTRODUCTION TO BIOLOGICAL CONTROL

1995 Final

1. I have read that Btk spores will last for a long time in the soil environment. So why were there so many applications made?

2. Transgenic cotton plants containing the Btk toxin have been planted to reduce herbivory by several caterpillar species. Unfortunately, one of them is a cutworm species (type IV insect) and is not susceptible to Btk. Among the following natural enemies, select the best one that could be used for cutworm suppression of the larval stage that feeds on foliage. Assume that the natural enemies are commercially available. Defend your answer. State why the others were not selected.

Steinernema carpocapsae
Nuclear ployhedrosis virus of the cutworm
Beauveria bassiana
Trichogramma sp.
Microsporidia of the cutworm

3. Compare and contrast between a direct deleterious effect and an indirect deleterious effect of a pathogen upon parasitoids. Give an example of each.

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