- Fruits: general small fruits
- Pest Management: general pest management
Recently, multiple vineyards throughout the state of Oregon have developed symptoms of Short Shoot Syndrome (SSS) which is believed to be correlated with the eriophyid mite, Calepitrimerus vitis Nalepa (Perez-Moreno and Moraza-Zorilla 1998, Bernard M. 2005, Walton 2007). This vineyard specific pest feeds on developing buds of early season cane growth which can result in stunted shoots, shortened inter-nodal growth and crop loss due to cluster necrosis. In all vineyards, active fungicide programs are maintained with heavy reliance on sulfur sprays for powdery mildew control throughout the growing season. It is hypothesized that these intense spray programs are a contributing factor of increased rust mite populations (secondary pest outbreaks) because of their detrimental effects on predatory mites and other beneficial arthropods (James 2002, Zalom 1997, Overmeer and Van Zon 1981, Duso 1992). Typhlodromus (=Galendromus) pyri Shueten has been documented as the predominant predatory mite species in western Oregon vineyards and is reported to be highly sensitive to a number of pesticides (Prischmann 2002, Walton 2007, Candolfi 1999). Typhlodromus pyri has a vast geographic range and it is believed that T. pyri can play an integral role in managing Calepitrimerus vitis populations in western Oregon vineyards. However, there is limited research available on this relationship. There is also little information regarding the foraging preferences and rates of T. pyri in terms of predation on C. vitis. The exploitation of chemical compounds has become an important strategy used in integrated pest management with the benefits of reducing pesticide applications. Methyl salicylate, an herbivore induced plant volatile, has shown evidence as a field attractant for some species of beneficial insects in vineyards and hops (James 2003, James and Price 2004). However, there is no evidence to date regarding the use of methyl salicylate to attract and optimize the behavioral activity of T. pyri in western Oregon vineyards. Preservation, enhancement and additional biological knowledge of these predatory mite populations are important aspects to implementing integrated pest management strategies into Western US vineyards.
Project objectives from proposal:
I. To determine the toxicity of numerous fungicides applied in vineyard systems on the predatory mite Typhlodromus pyri. Trials will be conducted in both the field and in laboratory bioassays to determine the effects on population density, mortality (juvenile and adult), fecundity, oviposition rate and longevity.
II. To address and determine the biology and foraging behaviors of Typhlodromus pyri, particularly in terms of predation on C. vitis. Predation preferences will be tested by comparing foraging on C. vitis versus alternative food resources under laboratory choice and no choice experiments. The rate of predation on C. vitis under choice and no choice conditions will also be determined.
III. To test the feasibility of employing methyl salicylate lures to attract and establish increased populations of T. pyri in vineyard systems. Field trials and laboratory experiments will be conducted to determine the attraction rate of T. pyri to this volatile compound.