Aquatic Plant Control Research Program. A Survey of the Continental United States for Pathogens of Eurasian Watermilfoil

摘要

A survey of the continental United States for pathogens of Myriophyllum spicatum (Eurasian watermilfoil) was conducted. More than 50 water bodies, located in 10 states, were sampled for diseased plants. Sample sites represented a geographic and climatic cross section of aquatic systems in the continental United States, including ponds, lakes, reservoirs, rivers, and canals. At the conclusion of the survey, 792 isolates had been collected from tissue samples and maintained in pure culture. Of these, 462 were bacteria and 330 were fungi; many isolates were duplicates but were retained because they possibly represented different strains of the same species. Lytic enzyme assays indicated that 14 bacterial and 22 fungal isolates produced pectinase or cellulose. Enzyme assays were used to screen for the more promising isolates for additional study as potential biocontrol agents for the management of Eurasian watermilfoil. The 32 isolates were then assayed healthy sprigs of the target species in test tubes. Results indicated that five fungal isolates should be considered for additional study.