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Date of Award


Document Type

Restricted Thesis: Campus only access

Degree Name

Bachelor of Science



First Advisor

Dr. Lisa Muehlstein


Changes in the populations of soil microorganisms were studies in response to additions of two residentially applied pesticides, Weed-B-Gon and Spectracide in both the field and laboratory. The study examined whether commercial pesticides used in residential areas. impacted microbial populations, therefore possibly precipitating a reduction in soil fertility. In the field study, soil samples were taken from randomized plots following initial pesticide applications and analyzed using standard microbiological plating techniques. In the laboratory study, microbial isolates were inoculated into nutrient broth containing pesticides in equivalent concentrations as applied in the field, and microbial growth was measured over time using a spectrophotometer. Field studies showed that an increased concentration of Spectracide indicating a misuse of the pesticide, caused a decrease in microbial numbers, impacting the ecological balance of the soil microbial community. Laboratory studies determined that the pesticides had a strong, differential impact on a microbial isolate with Spectracide promoting delayed growth and Weed-B-Gon inhibiting growth. The negative impacts of residentially applied pesticides on soil communities indicate that an important environmental issue is being overlooked since most of the current research concentrates on agricultural pesticides.