US EPA

2832430 

Journal Article 

The potential role of an endophytic fungus in the decline of stressed Eurasian watermilfoil 

Shearer, JF 

2002 

Yes 

Journal of Aquatic Plant Management
ISSN: 0146-6623 

40 

76-78 

WOS:000179019800007 

A greenhouse study was conducted to test effects of stress induced by simulated chemical runoff on endophyte-infected [Mycoleptodiscus terrestris (Gerd.) Ostazeski] and endophyte-free Eurasian watermilfoil (Myriophyllum spicatum L.). Simulated chemical runoff stress was induced by applying low rates of the herbicide endothall (dipotassium salt of 7-oxybicyclo {2,2,1}heptane-2, 3-dicarboxylic acid) for a 24-hour exposure time. Treatments included 0.5 and 1.0 mg L-1 endothall applied to endophyte-infected and endophyte-free Eurasian watermilfoil plants and untreated controls. Four weeks after herbicide application, shoot dry weight of Eurasian watermilfoil endophyte-infected plants was reduced by 75% and 72% when exposed to rates of 1.0 and 0.5 mg L-1 of endothall respectively compared to the endophyte-infected control plants. The shoot dry weight of endophyte-free plants was reduced by 58.2% and 30.8% respectively compared to the endophyte-free control plants. The presence of M. terrestris as an endophyte that has the potential to behave as a latent pathogen may lessen the ability of some Eurasian watermilfoil populations to survive stress conditions. Stress conditions appeared to weaken plants and render them susceptible to attack from an otherwise benign organism. 

Myriophyllum spicatum; fungal endophyte; Mycoleptodiscus terrestris