2nd Place: Investigating chemoreception and behavioural responses of Tetranychus urticae koch to naturally-based repellents and Acaricides

Monday, November 14, 2022

9:36 AM – 9:48 AM PT

Location: Vancouver Convention Centre, Meeting Room 114/115

Presenting Author(s)

Kayla H. Gaudet

MSc Student / Researcher
Acadia University
Canning, Nova Scotia, Canada

Co-Author(s)

NH

N. Kirk Hillier

Professor
Acadia University
Wolfville, Nova Scotia, Canada
Nicoletta Faraone

Assistant Professor
Acadia University
Wolfville, Nova Scotia, Canada

Tetranychus urticae Koch (two-spotted spider mite) is a worldwide multi-host agricultural pest that has rapidly developed resistance to a variety of synthetic chemical pesticides due to its high fecundity and short generation time. Plant essential oils have been recognized as a novel natural source of pest control that have a reduced impact to the environment and human health from synthetic pesticide application, and which may provide a viable alternative for managing this pest. The present study assesses the potential of plant-derived products as repellents and miticides. A novel electrophysiological approach (electrotarsography) was developed to record olfactory sensitivity of T. urticae. Additionally, a novel two-choice behavioural assay was designed to determine whether T. urticae is attracted or repelled by selected compounds. Using Gas Chromatogram-linked to electrotarsographic detection (GC-ETD), we determined that T. urticae is sensitive to many terpenoids commonly found in essential oil mixtures, such as eucalyptol, thymol, and linalool. In addition, T. urticae was sensitive to carboxylic acids and a series of aldehydes, which are typically detected by ionotropic receptors. In two-choice behavioural assays, T. urticae was repelled by various essential oil mixtures, as well as carboxylic acids and aldehydes. In an effort to further identify compounds of behavioural relevance for T. urticae, collections of volatiles from mites were made using thermal desorption linked with GC-MS analysis. The study provides novel insight to identify behaviourally relevant chemical cues for the development of mite control strategies.