ARS | Publication request: Olfactoryresponse of the predatory mite Typhlodromus pyri (Acari: Phytoseiidae) to methyl salicylate in laboratory bioassays

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 13, 2011
Publication Date: September 12, 2011
Citation: Gadino, A., Walton, V., Lee, J.C. 2011. Olfactoryresponse of the predatory mite Typhlodromus pyri (Acari: Phytoseiidae) to methyl salicylate in laboratory bioassays. Journal of Applied Entomology. DOI:10.1111/j.1439-0418.2011.01670.x.

Interpretive Summary: Typhlodromus pyri is a predatory mite that can control plant-feeding mite pests, including grapevine rust mite. Methyl salicylate (MeSA) is a volatile released by plants when attacked by herbivores, and MeSA can likewise attract predators to the plant. Addition of synthetic MeSA in crop fields has the potential to draw in predators and increase biological control activity. A study was conducted to determine which concentrations of MeSA would be most attractive to the predatory mite. Six doses ranging from 0.002 to 200 µg of diluted MeSA were tested. In a y-shaped olfactometer, air with MeSA was blown from one end, and the control volatile hexane was blown from the other end. Each mite was placed at the end of the y-tube and observed for which end it walked towards. Significantly higher proportions of T. pyri preferred MeSA at doses 0.02, 0.2, and 20 µg over the control. No differences were detected at the highest (200 µg) and lowest (0.002 µg) doses. The dose-response relationship was observed but not significant, suggesting there is a marginal relationship between dose quantity and T. pyri response. These results suggest that employing MeSA may potentially attract and retain predatory mite populations in vineyards and help control grapevine rust mite.

Technical Abstract: The response of Typhlodromus pyri, a key predator of grapevine rust mite (Calepitrimerus vitis), to MeSA was tested using a Y-tube olfactometer in laboratory bioassays. Six doses ranging from 200 to 0.002 µg of diluted MeSA were tested. Significantly higher proportions of T. pyri preferred MeSA at doses 0.02 (P = 0.007), 0.2 (P < 0.001), and 20µg (P < 0.001). No differences were detected at the highest (200 µg) and lowest (0.002 µg) doses. The variation in T. pyri's attraction to different MeSA doses was observed to be dose-dependent, but only marginally significant (P = 0.054). Results indicate that employing MeSA may be an effective strategy to attract and retain predatory arthropod populations in vineyards enhancing biological control of grapevine rust mite.