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p r a c t i c a l w i n e r y & v i n e ya r d a p r i l 2 0 1 4 67 g r a p e g r o w i n g models for how air turbulence impacts pathogen dispersion. A d a p t i n g a m o d e l i n g a p p ro a c h developed to predict particle move- ment in urban environments, we have begun investigating how canopy archi- tecture (vine row spacing and leaf area) influence air turbulence and particle movement in vineyards. Using these models we have predicted several phe- nomenon that have been observed in vineyards. For example, GPM disease foci tend to be elongated along vine rows (particu- larly in vineyards with wide tractor rows). The models indicate that this elon- gation is caused by eddies that form and move up and down the wider tractor rows. The eddies deposit spores onto vines further down the same vine row or on the ground and rarely eject them into the turbulent mixing layer for long dis- tance dispersion. Data on the spatial distribution of E. necator clones from Michael Milgroom's group in Cornell (New York state), also supports the modeling results. They showed that clones of E. necator were located mostly along vine rows or several vine rows away. These models have the spatial resolution to predict E. necator deposition at a scale smaller than a vine and we are developing them to run on a laptop or over a server that is accessed with a smart phone. The future Where is this all going? This research is currently moving along two paths that will eventually merge. We are working with robotic engineers to automate spore trap placement and collection and add other vineyard-monitoring sensors to the traps. This research is also helping us develop a modeling system that could become a vineyard-simulation environ- ment that growers could use to test man- agement decisions before applying them in the field. Can you imagine plugging in a few management options into your smart- phone and seeing the differences in how a simulated vineyard develops? How about spending a few weeks running simula- tions training to manage a new vineyard or bring a new manager up to speed? We realize this all sounds a bit far- fetched; however, how many of you would have guessed that that the smart- phone in your pocket has the processing power of an $8 million Cary-1 supercom- puter in 1976? The speed of technology development continues to increase and will likely make the goals above seem short sighted in 20 years. PWV Bibliography 1. Falacy, J.S., G.G. Grove, W.F. Mahaffee, H. Galloway, D.A. Glawe, R.C. Larsen and G.J. Vandermark. 2007 "Detection of Erysiphe necator in air samples using the polymerase chain reaction and species-specific primers." Phytopathology 97: 1290– 1297. 2. Mahaffee, W.F. 2014. "Use of air- borne inoculum detection for disease management decisions." In: Detection and Diagnostics of Plant Pathogens, M. L. Gullino and P. Bonants, Eds. Springer Verlag, N.Y. (in press). 3. Hall, T. 2000. Epidemiology of grape powdery mildew, Uncinula necator, in the Willamette Valley (master's thesis). Oregon State University, Corvallis, Ore. Use of inoculum detection could result in $6 million annual savings for Oregon growers.