Phytopathology (1996) 86, p. S60 (Vincelli et al.)

P. Vincelli, J.C. Doney Jr. and L. Wang (1996)
Dynamics of apothecial populations of Sclerotinia trifoliorum
Phytopathology 86 (11 suppl.), S60-S60
Abstract: Populations of apothecia of Sclerotinia trlfoliorum were monitored during the autumn/winter of 1991-92 (one site) and again during 1995-96 (two sites). In all instances, apothecia first emerged between 16 Oct and 25 Oct and were produced over a 9- to 12-wk period. Apothecial density reached a seasonal peak within two weeks of first detection and generally was highest during the first 4-6 wk of production, notwithstanding population fluctuations due to prevailing weather conditions. Using weather data available for the site in 1991-92 and for one site in 1995-96, we detected apothecia after the mean daily soil temperature at a 4-inch depth under grass or alfalfa dropped below 12.8°C followed by 0.25 inch or more of rainfall, although stipes may have been developing prior to these conditions. Minimum air temperatures at or below -5°C were associated with reduction of 50-100% in apothecial density. Studies to understand the dynamics of apothecial populations of S. trifoliorum and the influence of weather events are continuing.
Database assignments for author(s): Paul Vincelli

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Sclerotinia trifoliorum	Alfalfa/lucerne (Medicago sativa)