Evaluation of methyl salicylate lures on populations of Typhlodromus pyri (Acari: Phytoseiidae) and other natural enemies in western Oregon vineyards

Abstract

Methyl salicylate (MeSA), a herbivore-induced plant volatile, can elicit control of pests through attraction of beneficial arthropods. This study evaluates the effect of synthetic MeSA lures (PredaLure) on arthropod populations during the 2009 and 2010 seasons in two Oregon vineyards (Dayton and Salem). MeSA lures were deployed at a low (4/plot or 260 lures/ha) and high (8/plot or 520 lures/ha) rate in ∼152m2 plots while control plots contained no lure. The predatory mite Typhlodromus pyri Scheuten is considered to be a key biological control agent of the grapevine rust mite, Calepitrimerus vitis Nalepa in Oregon vineyards. Leaf samples were collected to assess T. pyri, C. vitis, spider mite (Tetranychidae) and thrips (Thripidae) population densities in MeSA treated plots compared to control plots. Yellow sticky traps were used to monitor other key predator groups including Anthocoridae, Araneae, Coccinellidae and Syrphidae. Our data did not display consistent trends in T. pyri response to MeSA between treatments at the two field sites over two seasons. Mean seasonal coccinellid counts were significantly higher in MeSA treatments in both years at Dayton. No differences in C. vitis population densities were found between treatments in both years. In 2009 at Salem, significantly lower pest thrips densities occurred in low rate MeSA treatments in the latter part of the season although no trend of decreased seasonal abundance was evident.