Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)


Agricultural, Environmental, and Sustainability Sciences

First Advisor

Dr. Alexis Racelis

Second Advisor

Dr. Rupesh Kariyat

Third Advisor

Dr. Pushpa Soti


Silverleaf nightshade (Solanum elaeagnifolium Cav.) is a perennial forb native to South Texas and Central and South America, but it has become a serious agricultural weed across the world. Because silverleaf nightshade (SLN) is difficult and expensive to manage using chemical and mechanical controls, there is growing attention and research focused on biological control options. In this project, we used both field and laboratory studies to examine the suitability of two North American insects, namely North American lacebug (Gargaphia arizonica Drake & Carvalho) and Texas false potato beetle (Leptinotarsa texana Schaeffer) as prospective biological control agents for SLN. Using a reverse interspersion design and a common-garden field trial, SLN was planted alongside two close solanaceous relatives, eggplant (Solanum melongena L.) and potato (Solanum tuberosum L.) Data from over two seasons of field experiments found that L. texana fed on eggplant and SLN but was rarely found on potato. Over the same period, G. arizonica was only found feeding on SLN, except for a single adult observation on eggplant in year 1 (with no observed feeding). However, in laboratory trials, moderate feeding damage by G. arizonica occurred on both eggplant and potato in no-choice experiments. Although feeding damage and survival of G. arizonica nymphs on eggplant and potato was not as extensive as that found on SLN, more research on the fundamental and realized host range of this insect is needed if it is to be considered for classical biological control.


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