Phytopathology (2010) 100, 1240-1249

Michelle M. Moyer, David M. Gadoury, Lance Cadle-Davidson, Ian B. Dry, Peter A. Magarey, Wayne F. Wilcox and Robert C. Seem (2010)
Effects of acute low-temperature events on development of Erysiphe necator and susceptibility of Vitis vinifera
Phytopathology 100 (11), 1240-1249
Abstract: Growth and development of Erysiphe necator (syn. Uncinula necator) has been extensively studied under controlled conditions, primarily with a focus on development of grapevine powdery mildew within the optimal temperature range and the lethal effects of high temperatures. However, little is known of the effect of cold temperatures (above freezing but <8°C) on pathogen development or host resistance. Pretreatment of susceptible Vitis vinifera leaf tissue by exposure to cold temperatures (2 to <8°C for 2 to 8 h) reduced infection efficiency and colony expansion when tissues were subsequently inoculated. Furthermore, nascent colonies exposed to similar cold events exhibited hyphal mortality, reduced expansion, and increased latent periods. Historical weather data and an analysis of the radiational cooling of leaf tissues in the field indicated that early-season cold events capable of inducing the foregoing responses occur commonly and frequently across many if not most viticultural regions worldwide. These phenomena may partially explain (i) the unexpectedly slow development of powdery mildew during the first month after budbreak in some regions and (ii) the sudden increase in epidemic development once seasonal temperatures increase above the threshold for acute cold events.
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Database assignments for author(s): Michelle M. Moyer

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Erysiphe necator	Grapevine (Vitis)