Effect of sublethal dose of Spinosyn A and D on Trichoplusia ni caterpillar eggs on the development of the egg parasitoid, Trichogramma brassicae
Plant Science Research Horizons seminar with MSc student Ryan J. Smith, Live on Zoom.
Pesticide overuse/misuse is a major problem, causing numerous issues,among them inducing pesticide resistance in pest species. Integrated Pest Management (IPM) seeks to combine different management strategies to support sustainable agroecosystems. Biocontrol is one successful IPM strategy. Trichogramma are popular choices for biocontrol species of Lepidopteran pests. They are minute parasitoid wasps that lay their eggs in Lepidopteran host eggs, killing the host before it hatches and damages crops. Employing biocontrol in conjunction with chemical control can be effective, however it is essential to understand how the pesticides will interact with the biocontrol species if a successful IPM program is to be created. This study seeks to study the effects of sublethal doses of pesticide active ingredients (Spinosyn A and D) used to manage the cabbage looper, Trichoplusia ni, a prolific pest of cruciferous crops that has evolved resistance to several pesticides. Spinosad (Spinosyn A+D), a fermentation product of the soil bacterium, Saccharopolyspora spinosa, presents an effective alternative biopesticide for T. ni management, however, Spinosad is also known to negatively impact Hymenoptera like Trichogramma. The development of the parasitoid Trichogramma brassicae will be studied in T. nieggs that have been exposed to a sublethal dose of spinosad using morphometrics and micro-CT scanning techniques. As well, Trichogramma diapause and stress-related genes will be measured to further characterize the effects of spinosad-treated eggs on parasitoid development and stress.