Date of Award:
5-1-1996
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Biology
Committee Chair(s)
Edward W. Evans
Committee
Edward W. Evans
Committee
Diane G. Alston
Committee
Mary E. Barkworth
Committee
Vincent J. Tepedino
Abstract
Grasshopper control is often accomplished through application of broad-spectrum insecticides that may also affect many non-target arthropods. To assess whether these insecticides reduce pollinator numbers and hence plant reproductive success, three forb species were examined. Potentilla fruticosa and Calylophus serrulatus were sampled before, immediately after, and approximately one week after spraying. The seed number for both species declined marginally but significantly immediately after spraying. The average weight per achene was significantly lower in spray sites for Potentilla fruticosa, but no significant interaction of time by spray was found for either species. Also, for two germination characters there was no significant interaction of time by spray for either species. The third species (Monarda fistulosa), sampled one month after spraying, had a significantly higher seed set and proportion of seeds germinating in unsprayed sites. Pollinator exclusions from flowers were used to simulate spray effects, but revealed no significant effects. Effects on population and community dynamics are discussed.
Recommended Citation
DiGiacomo, Suzanne, "Effects of Insecticide Spraying for Grasshoppers on the Reproductive Success of Three Prairie Plant Species in Western North Dakota" (1996). Biology. 622.
https://digitalcommons.usu.edu/etd_biology/622
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