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Plant-Insect Ecosystems

Section Symposium

Biocontrol of Drosophila suzukii: Status Updates on Natural Enemies and Ecological Considerations

A method for sampling parasitized Drosophila suzukii puparia from the soil, with insights into parasitoid ecology and biological control impact

Tuesday, November 15, 2022

4:10 PM – 4:22 PM PT

Location: Vancouver Convention Centre, Meeting Room 204

Presenting Author(s)

CC

Clarissa A. Capko

Student
University of the Fraser Valley
Langley, British Columbia, Canada

Co-author(s)

JT

Jason Thiessen

Agriculture and Agri-Food Canada
Agassiz, British Columbia, Canada
LH

Lana Harach

University of the Fraser Valley
Abbotsford, British Columbia, Canada
Jessica L. Fraser

Master's Student
Université Laval
Port Moody, British Columbia, Canada
Michelle T. Franklin

Entomologist
Agriculture and Agri-Food Canada
Agassiz, British Columbia, Canada

Co-Author(s)

Paul K. Abram

Research Scientist
Agriculture and Agri-Food Canada
Agassiz, Québec, Canada

Methods to measure the diversity and biological control impact of parasitoids for the control of spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) (SWD) are being developed in support of biological control programs around the world. Existing methods to determine parasitism levels and parasitoid species composition focus on sampling SWD within fresh and rotting fruit. However, many SWD pupate in the soil or in dropped fruit, where additional parasitism could occur. The efficient extraction of SWD puparia from soil could offer new insights into the parasitoids’ biological control impact throughout the entire growing season, facilitate studies into their overwintering biology, and help confirm parasitoid establishment following intentional releases. Here we introduce a method for extracting parasitized SWD puparia from the soil through a sieve and flotation system, allowing for effective collection of puparia, from which parasitoids can then be reared. Using this method, we found six species of parasitoids at considerably different relative frequencies compared with fruit sampling observations, including some that are rarely detected. By measuring the development time of reared parasitoids in the laboratory and from bucket emergence traps in the field, we were able to predict and validate the timing of spring parasitoid emergence in the field.