Nelson, L.S., J.F. Shearer, and M.D. Netherland, 1998. Mesocosm Evaluation of Integrated Fluridone Fungal Pathogen Treatment on Four Submersed Plants, US Army Corps of Engineers.

Reprinted from Journal of Aquatic Plant Management (1998) 36(1): 73-77

Mesocosm Evaluation of Integrated Fluridone Fungal Pathogen Treatment on Four Submersed Plants

ABSTRACT
An outdoor mesocosm study was conducted to evaluate the efficacy and selectivity of the herbicide fluridone (l-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]4(lh)-pyridinone) and the fungal pathogen Mycoleptodiscus terrestris (Gerdd.) Ostazeski (Mt), applied alone and in combination with one another, against hydrilla (Hydrilla verticillata (L.f.) Royle), Eurasian watermilfoil (Myriophyllum spicatum L.), American pondweed (Potamogeton nodosus Poiret), and vallisneria (Vallisneria americana Michx.). Treatments included 5 µg/L fluridone, 100 and 200 colony forming units (CFU) per ml of Mt, integrated treatments of 5 µg/L fluridone + 100 or 200 CFU/ml Mt, and untreated controls. Treatment with either fluridone or 200 CFU/ml Mt alone was sufficient to reduce hydrilla growth by 40% 84 days after treatment (DAT); however, the combined application of Mt plus fluridone reduced biomass by 93% compared with untreated plants. Eurasian watermilfoil biomass was not affected by Mt alone and was equally inhibited with treatment of fluridone or fluridone with Mt (75% reduction at 84 DAT). Treatments did not inhibit biomass production of American pondweed or vallisneria. With the exception of American pondweed, all treatments that included fluridone significantly reduced total chlorophyll. Results show that integrating a low dose of fluridone (5 pg/L) with Mt can effectively and selectively reduce hydrilla biomass with minimal effect to non-target plant species such as vallisneria and American pondweed, but may not improve control of Eurasian watermilfoil over fluridone alone.

Entire Paper
Contact: Linda Nelson, US Army Corps of Engineers, Waterways Experiment Station, CEWES-ES-P, 3909 Halls Ferry Road, Vicksburg, MS 39180
Keywords: Hydrilla, Chemical_control, Aquatic_plant_management
Product Type: Research, Control
User Type: Resource Management