Phytopathology (1997) 87, 576-581

M.L. Sutherland, S. Pearson and C.M. Brasier (1997)
The Influence of temperature and light on defoliation levels of elm by Dutch elm disease
Phytopathology 87 (6), 576-581
Abstract: The amount of defoliation of elm (Ulmus procera) caused by three Ophiostoma novo-ulmi Eurasian race isolates over 14 seasons of field trials was found to be strongly correlated with mean air temperature and mean number of sunshine hours over the 12-week period from inoculation to assessment, and with tree age. The coefficient of determination for the regression of percent defoliation on the environmental and tree factors was 0.76, P < 0.001 (33 df). Levels of defoliation were greatest when mean air temperatures exceeded 17°C with moderate light (5 to 7 h of sunshine), and lowest under conditions of either high light (>7.5 h of sunshine) at all air temperatures or low light (<4.5 h of sunshine) and air temperatures of less than 15.5°C. The model varied in its intercept for the three isolates, reflecting their different levels of aggressiveness. The role of environmental factors in the development of Dutch elm disease symptoms and the implications for elm resistance breeding are discussed.
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Database assignments for author(s): Clive M. Brasier

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

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ophiostoma novo-ulmi	Elm (Ulmus)	Czech Republic
	Ophiostoma novo-ulmi	Elm (Ulmus)	Germany
	Ophiostoma novo-ulmi	Elm (Ulmus)	United Kingdom