Theses and Dissertations

Date of Award

8-1-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Pushpa Soti

Second Advisor

Manohar Chakrabarti

Third Advisor

Alexis Racelis

Abstract

Silverleaf nightshade (Solanum elaeagnifolium) is a widespread invasive weed in South Texas and other arid regions, where it reduces crop productivity, competes with native vegetation, and resists conventional control methods. Its ability to thrive across different environments is linked to phenotypic plasticity, allowing it to adjust growth and physiology in response to light and water availability. In this thesis, I examine the role of plasticity in S. elaeagnifolium under field conditions and evaluate the potential of the North American lacebug (Gargaphia arizonica) as a biological control agent. Field observations were used to measure plant traits such as height, stem thickness, trichome density, flowering, stomatal conductance, and PSII efficiency across shaded and sun-exposed environments with varying soil moisture. A separate growth chamber experiment tested whether lacebug herbivory could effectively suppress plant growth and prevent regrowth. Plants were monitored for yellowing, defoliation, and lacebug persistence. The findings from this study provide insight into how S. elaeagnifolium responds to environmental stress and demonstrates the potential of G. arizonica as a host specific biocontrol agent to support long term weed management.

Comments

Copyright 2025 Marco Andre Silguero. All Rights Reserved. https://proquest.com/docview/3313405089

Download

Included in

Biology Commons

Share

COinS