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Theses/Dissertations

2013

Graduate Theses and Dissertations

Biological control

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Full-Text Articles in Life Sciences

Classical And Conservation Biological Control Of Pest Insects Within Prairie And Crop Systems, Rene Hessel Jan 2013

Classical And Conservation Biological Control Of Pest Insects Within Prairie And Crop Systems, Rene Hessel

Graduate Theses and Dissertations

The manipulation of beneficial insects can be done through purposeful releases of biological control organisms, or through manipulation of non-crop habitat. Both mechanisms are explored in various agroecosystems. In chapter 2, I determine if the parasitoid waspBinodoxys communis, imported from China, is able to colonize, and suppress soybean aphid, Aphis glycines in Iowa soybean fields. In addition, the effects of initial soybean aphid densities are measured. Binodoxys communis successfully colonized soybean aphids in Iowa soybean fields, but is not always effective at suppressing soybean aphid populations. Abiotic and biotic factors were more important for the suppression of soybean aphid ...


Fitness Costs Associated With Resistance To Cry3bb1 Corn In Western Corn Rootworm, Amanda Hoffmann Jan 2013

Fitness Costs Associated With Resistance To Cry3bb1 Corn In Western Corn Rootworm, Amanda Hoffmann

Graduate Theses and Dissertations

Crops producing toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely planted to manage insect pests, including western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), a significant maize pest. The evolution of resistance would diminish the effectiveness of this technology; however, fitness costs can delay resistance. We quantified the level of resistance and tested for fitness costs of resistance in western corn rootworm with resistance to transgenic maize (Zea mays L.) that produces the Bt toxin Cry3Bb1. Fitness costs were measured in two experiments with non-Bt maize, the first used three commercial hybrids and the second used three ...