Theses and Dissertations at Montana State University (MSU)
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Item The potential of sugar resources in the reproductive biology of wheat stem sawfly parasitoids(Montana State University - Bozeman, College of Agriculture, 2018) dos Reis, Dayane Andrade; Chairperson, Graduate Committee: David K. Weaver; Robert K. D. Peterson, Megan L. Hofland and David K. Weaver were co-authors of the article, 'Differences in longevity, egg load, and egg volume due to sucrose feeding in two sympatric congeneric braconids that are specialist parasitoids of the wheat stem sawfly ' which is contained within this thesis.; Robert K. D. Peterson, Megan L. Hofland and David K. Weaver were co-authors of the article, 'The effect of cultivated and native floral species as resources in the reproductive biology of wheat stem sawfly parasitoids' which is contained within this thesis.The wheat stem sawfly, Cephus cinctus, is the most destructive insect pest of wheat, Triticum aestivum, in the Northern Great Plains of North America. Biological control by Bracon cephi and Bracon lissogaster is an important tool for integrated pest management of this pest, but parasitism rates are difficult to predict. Therefore, the main objective of this research was to characterize aspects of the reproductive biology of both parasitoid species to provide information that could enhance their effectiveness in biological control of C. cinctus. First, we investigated the role of diapause and the effects of sucrose feeding on reproduction of females. For that, we provided sucrose solution to overwintering and summer generation adult females, and we quantified and compared their longevity, egg load and egg volume. Our results showed no differences between overwintering and summer individuals of B. cephi and B. lissogaster. In contrast, sucrose feeding, increased longevity and egg load of both species and generations. The egg load of B. cephi was surprisingly low compared to B. lissogaster. However, only B. cephi increased egg volume when sucrose was provided. Our findings highlighted the contrasting life histories of both species, and showed the potential of sugar resources in enhancing their reproductive capacity. Subsequently, we investigated the effect of flower nectar on the same, above mentioned, reproductive traits of parasitoids. We chose buckwheat (Fagopyrum esculentum), lacy phacelia (Phacelia tanacetifolia), deerhorn clarkia (Clarkia pulchella), canola (Brassica napus), and safflower (Carthamus tinctorius) based on their occurrence as native plants, use in pollinator enhancement, and occurrence in rotational or cover crop plantings in Montana. We found that only B. cephi females benefitted from these flowering plants. The longevity and egg volume of females increased with buckwheat, and egg volume increased with both buckwheat and the native species, deerhorn clarkia. The strong effect of buckwheat on reproduction of B. cephi females suggests that flowers with similar nectar quality might have similar impacts. This information will be of great importance for selection of suitable flower species to enhance reproductive capacity of parasitoids through habitat management. Collectively, this research showed that there is potential to enhance effectiveness of parasitoids with sugar supplementation.Item Effects of precipitated calcium carbonate from sugar purification on crusting soils(Montana State University - Bozeman, College of Agriculture, 1996) Inkret, John MatthewPrecipitated calcium carbonate (PCC), a by-product of the sugar industry, results from a sucrose juice purification technique. This material has several properties that distinguish it from geological calcite. These properties include an organic load, high water-holding capacity, small particle size, high surface area, and uniformity. A large stockpile of PCC is located at the Holly Sugar refinery in Sidney, Montana. This study was initiated at the request of Holly Sugar to investigate potential PCC application as a soil amendment to local agricultural soils that exhibit surface crusting. Soil surface crusts, initiated by precipitation events, are common in Eastern Montana. These crusts can significantly inhibit crop seedling emergence. This study was designed to evaluate the potential of PCC to ameliorate crust formation in eastern Montana agricultural soils. Bulk soil samples from four different sites and stockpile PCC samples were collected for evaluation. Amendment (PCC) and the four soils were then physically and chemically characterized. Soil crust formation and strength of amended and control soils were evaluated in the laboratory and greenhouse by inducing crust formation and then measuring and analyzing specific soil crust properties and parameters. Soil areal extensibilities from saturated to dry moisture conditions were measured and evaluated. Outdoor trials evaluated seedling emergence success and surface crust strength. Greenhouse trials evaluated seedling emergence and the areal extent of soil surface fractures by a photographic quantification technique. The addition of PCC, at the rates tested, did not ameliorate the problematic physical characteristic of the soils. Soil crusting was not reduced by the amendments used in this study.