X hits on this document

475 views

0 shares

0 downloads

0 comments

110 / 164

Florida Lake Management Society Annual Conference, Naples, Florida, June 4 – 7, 2007

THE IMPACT OF FLURIDONE ON TARGET AND NON-TARGET PLANT SPECIES: DATA FROM MONITORING OF ACTUAL LAKE TREATMENTS

Ken Wagner, Ph.D., ENSR Willington, CT

Fluridone, the active ingredient in the herbicide SONAR, is a systemic compound that is less acutely toxic that most other herbicides. This creates some challenges for maintaining adequate exposure, but also creates opportunity for managing plants selectively. Use history can

be

described as:

  • Fluridone, as Sonar, has been in use for up to 20 years in some states and a minimum of 10 years in others

  • Four Sonar forms available: liquid (AS) and 3 pellets (SRP, PR, Q)

  • Doses are typically 5-20 ppb AS, about 50 ppb for pellets

  • Recommended exposure time varies by application, but >60 days is desired and >90 days is preferred at >2-4 ppb

  • Measurement of in-lake concentrations is simple and common (FasTEST), with detection down to about 0.5 ppb

  • Assessment of likely or actual impact by biochemical means is available (PlanTEST and EffecTEST)

  • Greater knowledge of impacts on wider range of plant species, although most information has not been organized and systematically evaluated.

Creative use can be described as follows:

  • Lower doses at longer exposure times

  • Sequestered treatments (partial lake treatment)

  • Choice of release rates for pelletized formulations

  • Bump/drip treatments (sequential additions)

  • Tracking of concentrations

  • Evaluation of likely and actual impacts on plant species

Data from plant monitoring programs associated with field treatments have been used to evaluate the impact on individual plant species of each of four treatment classes based on initial dose and duration of exposure. Some species are more susceptible than others, some recover more rapidly, some are very opportunistic after treatment, and some respond with such variability that prediction of impact is difficult. Plants that decline under nearly all treatment conditions include Eurasian watermilfoil - Myriophyllum spicatum, Northern watermilfoil - M. sibiricum, Naiad – Najas, Waterweed – Elodea, Water marigold - Bidens beckii. Plants that are stable or increase after nearly all treatments include Stonewort – Chara, Nitella – Nitella, Water Stargrass – Zosterella, Bladderwort – Utricularia, Floating leaf pondweed - Potamogeton natans. Species that react differently at different concentrations often used in treatments include Water celery – Vallisneria, Yellow water lily – Nuphar, Water lily – Nymphaea, Fanwort – Cabomba caroliniana, Some pondweeds – Potamogeton amplifolius, P. gramineus, P. zosteriformis. Species that often appear after treatment when not present beforehand include

Session 6A – Page 4

Document info
Document views475
Page views475
Page last viewedSun Dec 11 06:48:37 UTC 2016
Pages164
Paragraphs2961
Words43681

Comments