TY - JOUR T1 - Impact of Vine Shelter Use on Development of Grape Powdery Mildew JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 204 LP - 209 DO - 10.5344/ajev.2001.52.3.204 VL - 52 IS - 3 AU - Tyrone W. Hall AU - Walter F. Mahaffee Y1 - 2001/01/01 UR - http://www.ajevonline.org/content/52/3/204.abstract N2 - Heavy infection of powdery mildew, Uncinula necator, on grapevines was observed in conjunction with vine shelter use during the 1997 growing season in the Oregon Willamette Valley. The influence of vine shelter use on the development of powdery mildew was investigated in the field during the 1998 and 1999 growing seasons. Installations of vine shelters were examined for both incidence and severity of U. necator infection. Five brands and four installation types were examined. There were no significant differences among brands of vine shelters. The industry standard installation of 76 cm high tubes, hilled with 7.6 cm of soil at the bottom to prevent airflow, resulted in significantly lower incidence of powdery mildew in both field seasons. Significantly increased disease incidence was observed in installations designed to increase airflow in the shelters. Reduction in incidence of disease on leaves was significantly correlated with prolonged temperatures above 36°C within the vine shelters. Vine length was significantly increased depending on shelter brand and installation type in both years.Acknowledgments: The authors thank Julie DiLeone, Carolyn Swenson, and Kelly Donahue for assistance with assessment and Jay Pscheidt, Ed Hellman, and Ken Johnson for critical review of the manuscript. Mention of trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the USDA and does not imply its approval to the exclusion of the products or vendors that may also be suitable. This research was written by federal employees as part of their jobs and is considered to be in the public domain. ER -