PUBLICATION NOTICE: Demonstration and Evaluation of Eurasian Watermilfoil Control using Aquatic Herbicides in Fort Peck Lake, MT

The US Army Engineer Research and Development Center has published the report/note described and linked below. Approved for public release; distribution is unlimited.

Report Number:

ERDC/EL TR-19-16

Title:

Demonstration and Evaluation of Eurasian Watermilfoil Control using Aquatic Herbicides in Fort Peck Lake, MT

Author(s):

Rebecca L. Podkowka, Kurt D. Getsinger, John G. Skogerboe, Patricia L. Gilbert, and Toni G. Pennington

Purpose/Abstract:

Eurasian watermilfoil (EWM) was first observed in Fort Peck Lake, MT in 2010 and has spread to over 100 locations in the lake. In 2012, field trials were conducted to evaluate aquatic herbicides for controlling EWM and provide management guidance. This work follows those initial 2012 demonstrations. Five sites were identified for herbicide treatments and bulk water exchange processes were determined using inert tracer dye, rhodamine WT (RWT). Field trials conducted in 2014 spanned two growing seasons, summer (July) and fall (September). Treatments were with a variable-depth application technique, or for one plot, a hand gun from the surface. Vegetative communities were assessed at pretreatment, and at 8 and 52 weeks.  Non-target native vegetation was sparse pretreatment in all plots, but generally survived treatments. Treatments had no impacts on water quality measured in the field, including dissolved oxygen levels. Control of EWM was limited (< 50%) in small, open-water plots treated with diquat and endothall, where no barrier curtains were deployed. Control of EWM was near 100% through one year after treatment in plots where barrier curtains mitigated bulk water exchange processes and extended herbicide contact times were maintained.

63 pgs / 4.9 mb

CLASSIFICATION: UNCLASSIFIED

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