MSc Final Oral Examination: Laxmi Khadka


Interested Members of the University Community are invited to attend the Final Oral Examination for the Degree of Master of Science of Laxmi Khadka of the Department of Plant Agriculture

Date: Wednesday, May 20, 2020
Time: 9.30 AM

Delivered via Zoom

To join the seminar using Zoom Meeting please email

Thesis Title: Effect of hexanal formulation on host recognition and oviposition behaviour of spotted-wing drosophila (Drosophila suzukii) (Matsumura).

Advisory Committee
Dr. Cynthia Scott-Dupree, Advisor
Dr. Gopi Paliyath, Co-advisor
Dr. Loong Tak-Lim

Examination Committee
Dr. Katerina Jordan (Chair)
Dr. Cynthia Scott-Dupree
Dr. Gopi Paliyath
Dr. Mary Ruth McDonald


Hexanal is a volatile aldehyde synthesized naturally in plants. Hexanal based technologies (preharvest spray, postharvest dips or vapour treatment) delay senescence in fruit and ensure longer shelf-life.  Hexanal also exhibits antimicrobial and antifungal properties and may repel insect pests. This thesis assessed the fruit choice behaviour of SWD exposed to strawberries and blueberries and oviposition efficacy of spotted-wing drosophila (SWD) (Drosophila suzukii) exposed to blueberries at three fruit maturity stages (early, mid and late) either hexanal treated or untreated. Furthermore, the qualitative and quantitative profiles of volatiles released from blueberries and strawberries at three fruit maturity stages and their quality parameters (i.e., firmness, pH, sugar content) were assessed. Hexanal formulation treatment had no effect on the fruit choice behaviour of SWD for the three fruit maturity stages of blueberries and strawberries. In addition, it didn’t effect SWD oviposition and resulting adult emergence on three fruit maturity stages of blueberries. Oviposition and adult emergence increased with an increase in sugar content and a decrease in the acidity of the fruit. Furthermore, oviposition and subsequent adult emergence decreased with an increase in fruit firmness. These laboratory findings suggest that the hexanal formulation (created by Dr. Paliyath and coworkers at the University of Guelph (US Patent # 6,514,914; 7, 198,811)) treatment tested on postharvest strawberries and blueberries may not be helpful for SWD field management.