PA W'21 Seminar Series


TITLE: Is biocontrol immune to resistance development?
           An investigation into changes in predatory defenses.

SPEAKER: Dr. Catherine Taraoff, Agrowest Consulting and Thompson Rivers University, British Columbia

LOCATION: Zoom (link available on request, please contact Dr. Francois Tardif )
TIME: 3:00 to 4:00 PM
DATE: Thursday, March 25th, 2021

Biocontrol is considered an effective management tool for a number of invasive species, including St. John’s wort. However, in 2018, possible biocontrol resistance was discovered at an historical Chrysolina sp. release location (St. John’s wort, release - 1952). Biochemical and physical differences were measured between susceptible and possibly resistant plants. ‘Resistant’ plants had significantly higher levels of the predatory defense biochemical hyperforin, reflected by a drastic reduction in defoliation. Resistant plants were significantly taller, had significantly greater leaf gland density, and significantly larger leaves than their susceptible counterparts within the population. Future research on this topic will include collecting seeds from ‘susceptible’ and ‘resistant’ plants within the population and measuring chemical and physical differences within the offspring.

Catherine graduated from Thompson Rivers University in 1998, after which she attended Oregon State University and earned a PhD in Crop Sciences with an emphasis on Weed Science, and a minor in Rangeland Ecology in 2007. Dr. Tarasoff went on to become the Invasive Plant Ecologist at Michigan Technological University. She recently moved back to British Columbia and runs her own consulting company and is adjunct faculty and a sessional instructor at Thompson Rivers University, in the Department of Natural Resource Sciences. She has been a Professional Agrologist for 20 years.

In this presentation, Catherine will present on the development of possible bio control resistance within a population of St. John’s wort (Hypericum perforatum). This work came about after land managers approached Catherine regarding the explosion of St. John’s wort on the landscape in British Columbia after many decades of successful biocontrol.