LE3 .A278 2020

2020

Hillier, Kirk

Acadia University

Bachelor of Science

Honours

Biology

Biology

The two-spotted spider mite (Tetranychus urticae Koch) is a polyphagous pest of many important plant species including kidney bean, tomato, and cannabis. An infestation by spider mites often results in the complete defoliation of a plant which makes T.urticae an economically important pest. To elucidate the mechanism by which T. urticae detects and selects a host plant, electrophysiological assays such as electrotarsogram (ETG) were developed to screen compounds of interest from a volatile blend. Volatile organic compounds (VOCs) were collected from kidney bean and tomato plants and were used to test for differential biological/behavioral sensitivity against T. urticae. Putative chemosensory responsesinduced by kidney bean plant volatiles in T. urticae were identified as 2-ethyl-1-hexanol, acetophenone, cis-3-hexenyl 3-methylbutanoate, and 1-(4-ethylphenyl)-ethanone. Putative chemosensory responses induced by tomato plant volatiles in T. urticae were identified as α-phellandrene, 2-ethyl-1-hexanol, acetophenone, β-phellandrene, and 1-(4-ethylphenyl)-ethanone. The identification of these compounds enhances our understanding of which chemical cues T. urticae perceives during host selection. To investigate host selection, behavioral assays were performed to determine spider mite preference between different host plants. We found that T. urticae significantly preferred kidney bean over tomato as a host plant in choice assays(P= 0.0009) and that they responded most strongly to kidney bean leaf in the no-choice assay (P=0.0002). The data collected from spider mite electrophysiology and behavioral studies will aid in the development of potential mite attractants/repellants and in the development pest management techniques for T. urticae.

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https://scholar.acadiau.ca/islandora/object/theses:3458