Document Type

Honors Thesis

Major

Biology

Advisor(s)

Allison Gardner

Committee Members

Philip Fanning, Ivan Fernandez

Graduation Year

May 2023

Publication Date

Spring 2023

Abstract

Ticks are obligate parasite arthropods that are becoming increasingly common in northern regions of the United States. Ticks such as the black-legged tick (Ixodes scapularis) and the American dog tick (Dermacentor variabilis) are vectors for pathogens that cause a wide range of diseases, and as these ticks increase their exposure to humans, the diseases they transmit become more prevalent. This upward trend in cases of tick-borne illnesses has necessitated the pursuit of tick control methods that can be used across the diverse environments that are present in tick habitat ranges. One such control method is the fungal biological control, Beauveria bassiana. This study investigates the effects of soil pH on B. bassiana as a tick control method, focusing on its effects on tick mortality and questing behavior. These variables were measured for I. scapularis and D. variabilis in a laboratory bioassay across soils with pH 6.5 and pH 5.4. No significant difference in mortality was observed between soil treatments without B. bassiana. The only significant difference in questing behavior was observed for I. scapularis nymphs between soil treatments without B. bassiana, which saw an increase in questing in more acidic soil. Difference in soil pH was not found to have a significant effect on B. bassiana and its effect of increased mortality on ticks. Beauveria bassiana application led to a significant increase in tick questing for all tick species and life stages in soil with pH 6.5. Application of B. bassiana was found only to significantly decrease questing behavior for I. scapularis adults in soil with pH 5.4.

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