Environmental influences on ascospore release of Ophiosphaerella agrostis under controlled and field conditions

Ophiosphaerella agrostis, the causal agent of dead spot of creeping bentgrass (Agrostis stolonifera), produces prodigious numbers of pseudothecia and ascospores throughout the summer. The objectives of this research were to: 1) determine the influence of changes in light and relative humidity on asc...

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Bibliographic Details
Published in:Phytopathology 2005-06, Vol.95 (6)
Main Authors: Kaminski, JE, Dernoeden, PH, O'Neill, N R
Format: Article
Language:English
Subjects:
Agrostis
Agrostis stolonifera
Ophiosphaerella agrostis
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Summary:Ophiosphaerella agrostis, the causal agent of dead spot of creeping bentgrass (Agrostis stolonifera), produces prodigious numbers of pseudothecia and ascospores throughout the summer. The objectives of this research were to: 1) determine the influence of changes in light and relative humidity on ascospore release; 2) document the seasonal and daily discharge patterns of ascospores; and 3) elucidate environmental conditions that promote ascospore release. In a growth chamber study, a sharp decrease in relative humidity resulted in a rapid discharge of ascospores, regardless of light. In field studies, ascospores were collected between May and October 2001-2002. Major ascospore release events generally occurred during the early morning and evening hours or during precipitation events. Few ascospores were released when the bentgrass canopy was dry. Ascospore discharge occurred in a cyclic pattern that peaked about every 12 days. New infection centers appeared approximately 3 to 10 days after a large release of ascospores.
ISSN:0031-949X