aquatic invasive weeds · introduction . management of aquatic weeds is complicated because: many...
TRANSCRIPT
Aquatic Invasive Weeds
Mark Sytsma Center for Lakes and Reservoirs
Aquatic Bioinvasion Research and Policy Institute Portland State University
Benton County CWMA Aquatic Applicator Short Workshop
Corvallis • 10 March 2016
Overview
Why manage invasive aquatic weeds? Some common and not-so-common invasive
species (focus on the Pacific Northwest) Options for aquatic plant management Some nonplant invasive species to watch for
Introduction Management of aquatic weeds is complicated
because: Many species are easily confused with native or legally
imported species Common names are confusing and often misapplied Many aquatic weeds reproduce vegetatively from small
fragments Water moves Aquatic systems contain many sensitive and endangered
iconic species that complicate management
Algae Microscopic
greens, diatoms, golden, dinoflagellates, cyanobacteria
Nitella Chara
Ecological impacts Reduce light penetration &
mixing Reduce species diversity Alter temperature, dissolved
oxygen & pH Degrade fish habitat Altered nutrient cycling can
lead to algae blooms and toxicity
Impacts on biodiversity
Madsen et al. 1991
Food web and nutrient cycling
Carpenter and Lodge 1986
Economic impacts Reduce flow in irrigation
canals and drainage ditches Increased cost of irrigation Flooding Clogged pumps & intake
structures Loss of recreational
resources Negative impacts on
property values
Human safety
Myriophyllum spicatum Eurasian watermilfoil
Feathery leaves divided into leaflets. 3 to 5 leaves grow in a whorled pattern around the stem.
When out of water, leaves lose their rigidity and collapse around the stem.
Easily confused with native milfoil species
Eurasian
watermilfoil Northern
watermilfoil
Myriophyllum spicatum x sibiricum Hybrid watermilfoil
Intermediate characteristics Rapidly spreading in Great Lakes
region Increased resistance to several
herbicides commonly used on EWM Confirmed in Howard Prairie
Reservoir & multiple sites along the Rogue River
Kev
Ale
xani
an
Myriophyllum heterophyllum variable leaf watermilfoil, two-leaf watermilfoil, & red foxtail
Siltcoos Lake, Oregon Present at 22 of 297 sampling
locations Extensive monocultures in protected
bays
Class A noxious weed in Washington 5 lakes being treated
Hydrilla verticillata Monecious biotype in Washington
(10yrs, $10M eradication) Dioecious biotype (only female)
thermally-influenced Bruneau River, Idaho Endangered snail present Diquat and handpulling
Hydrilla verticillata hydrilla, Florida elodea, water thyme
Egeria densa Brazilian elodea
Dioecious Only male plants outside native range in South
America Dispersal by fragments only Most common invasive aquatic plant in west-side lakes
Elodea canadensis/nutallii American waterweed, common elodea
Native species common throughout Oregon
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E. canadensis E. nutallii
Similarities in the Hydrocharitaceae U
SD
A P
LA
NT
S d
ata
base
Elodea
canadensis/nutallii
(native)
Egeria densa
(B-list noxious weed) Hydrilla verticillata
(A-list noxious weed)
Turions and tubers are features of hydrilla
Potamogeton crispus curly leaf pondweed
Common throughout Oregon Turions form in spring on small plants, sprout
in fall and overwinter Typically bimodal biomass curve – most
abundant in spring and fall, dies back in summer
Long-term control requires interrupting turion formation
Cabomba caroliniana
Appears to be restricted to low-pH, dystrophic (tea colored) lakes
Easily confused with submersed form of water buttercup (which has alternate leaves)
Ranunculus aquatilus
gobotany.newenglandw
ild.org
Ceratophyllum demersum coontail
Native Not rooted Bifurcated leaves Inconspicuous,
submersed flowers
Duckweeds
Mail-Tribune file photo
http://ww
w.ruduckweed.org/
duckweed
http://waynesword.palomar.edu/1wayindx.htm
Eichhornia crassipes water hyacinth
10 miles of thermally influenced Snake River infested eradicated
Umpqua River infestation
Salvinia molesta salvinia
Cryptobagous salviniae
Annual releases of Cryptobagous salviniae on Lower Colorado R.
Source: Dewey Murray, USDA APHIS PPQ
Efficacy of Cryptobagous salviniae on Lower Colorado R.
Photos: Dewey Murray, USDA APHIS PPQ
2004 2005
Limnobium laevigatum South American spongeplant
• Redding pond (June 2005) • 0.25 m2 quadrat: >2,000 plants • Chokes out water primrose and parrotfeather; grass growing on the mat • A-listed noxious weed in OR
Azolla pinnata feathered water fern
Federally listed noxious weed
Azolla filiculoides and A. mexicana
Natives
Nymphaea odorata fragrant water lily
Identification:
Rooted aquatic perennial Grows in depths of 3-6 feet Floating heart-shaped or
circular leaves (30 cm); purplish underneath, leathery, slit in one side
Large (6-12 cm) fragrant flowers; 20-30 petals, range of colors with yellow centers
Seed and rhizomes
Nymphoides peltata yellow floating heart
Native to East Asia A-listed noxious weed Scattered populations in
southern and eastern OR, and Portland metro areas
Bacopa rotundifolia disk water hyssop
Considered imperiled in neighboring states Herbarium specimen in WY from 1891and from ID in 1933
First occurrence in Oregon in Columbia River in 2014 Weedy in rice fields in CA What to do about it in Oregon?
Natureserve.org
Nuphar polysepala yellow pond-lily
NATIVE Similar habitat Larger, oval to heart-
shaped leaves with a prominent midvein
Flowers – yellow petals and centers, 9-petals
Brassenia schreberii watershield
NATIVE Similar
habitat Oval, peltate
leaves Inconspicous
flowers
Phalaris
arundinacea
Lythrum
salicaria
Iris
psuedacorus
Yellowflag Iris Purple loosestrife Reed canary grass
Cattails Typha latifolia
Native Typha angustifolia
Invasive X Typha glauca
hybrid
Phragmites australis reed
ssp. americanus ssp. australis
Sagittaria spp.
Sagittaria
graminea Class B in WA
(3 locations)
Sagittaria
platyphylla (1 lake in WA/
Blue Heron Wetland,
Portland
Potential noxious listing)
Sagittaria
rigida Class B in WA
(6 locations)
Myriophyllum aquaticum parrotfeather milfoil
Native to South America
Only female plants present
Dispersal by fragmentation
Difficult to control
Ludwigia spp. Water primrose water primrose
Abundant in middle reaches of the Willamette downstream to Columbia R.
Active control efforts underway Delta Ponds, Eugene Willamette (Willamette Riverkeepers)
Aquatic perennial Moving down Columbia River from infestation in Montana Large infestation in Yakima River Suction harvesting of small populations near McNary Dam Submersed and emergent growth forms Dispersal by rhizome fragments
Butomus umbellatus Flowering rush
Spartina spp. Estuarine cordgrasses
• 4 non-native, invasive species – S. alterniflora (Eastern & Gulf coast of North
America) – S. patens (Eastern & Gulf coast of North America) – S. anglica (hybrid of English S. maritima & S.
alterniflora) – S. densiflora (South America)
• 1 native (S. foliosa)in California • Hybrids
S. alterniflora
S. densiflora
S. patens
S. anglica
Known Spartina Distribution on the West Coast
Comox Harbor, BC Fanny Bay, BC Boundary Bay, BC Puget Sound, WA Gray’s Harbor, WA Willapa Bay, WA Columbia River Sand Lake, OR Siuslaw River, OR Coos Bay, OR Humboldt Bay, CA San Francisco Bay, CA
Aquatic Weed Control Methods
Biological Manual Physical Mechanical Chemical
Biological Control Options Purple loosestrife
Galerucella spp. (leaf feeding), Hylobius (root) & Nanophyes (flower/seed)
Very successful – reduction in growth, occurrence & competitiveness
Eurasian watermilfoil native weevil - Euhrychiopsis lecontei Results difficult to predict (fish predation,
overwintering habitat)
Grass Carp (Ctenopharyngodon idella) Generalist feeders – low/no selectivity Very limited applications “biological success” vs “impact success”
Manual Control Options
Hand-pulling, or underwater weeding Target specific weeds, move around
obstructions, minimal equipment Labor intensive, creates murky water
and fragments Rakes, cutters
Inexpensive Labor intensive, creates murky water
and fragments
Physical Control Options Benthic barriers
Sediment blanket that blocks light, compresses plants Controls rooted plants Expensive for large ponds Requires regular maintenance Interferes with bottom habitat Unruly to anchor in large ponds
Drawdown May be ineffective in wet conditions and without freezing Increase in some weeds (Potatmogeton, hydrilla)
Physical Control Options
Shading Aquatic dyes - preemergent,
depths > 2’ Labeled as herbicides
Weed rollers/rakes
www.TheWeedersDigest.com
Mechanical Control Options
Cutting and shredding boats (“cookie cutters”)
Rotovators – tills sediments Dredgers – sediment removal Harvesters – cut & remove
Pros: Site specific, public perception, use of
harvested biomass
Cons: Requires opens water surface & off-site disposal, $$$ Creates fragments Nonselective, by-catch
Chemical Control Options
Prerequisites for Efficacy Adequate Concentration
Adequate Contact Time
Appropriate Water Quality • Turbidity interferes with diquat
Optimal season and phenological stage
Appropriate chemical for weed species • 2,4-d for dicots
EPA registered herbicides for aquatic use Contact Systemic
Selective Copper Peroxygen granular (GreenClean®
& Phycomycin®)
2,4-D (Aquaclean/
Navigate) Triclopyr (Renovate)
Fluridone (Sonar) Penoxsulam (Galleon)
Bispyribac-sodium (Tradewind)
Broad
spectrum
Endothall, dipotassium salt (Aquathol)
Diquat (Reward) Carfentrazone (Stingray)
Flumioxazin (Clipper)
Glyphosate (Rodeo) Imazapyr (Habitat) Fluridone (Sonar)
Imazamox (Clearcast)
Mention of tradenames does not indicate endorsement – compounds may be available from multiple manufactures and under different tradenames
Aquatic Herbicides Broad spectrum contact herbicides
Endothall (Aquathol K)
• Inhibits respiration & protein synthesis • Typically non-selective (early season applications can control
over-wintering or early emerging weeds) • Liquid and pellet formulations allow spot treatment • Not affected by alkalinity or turbidity
Diquat (Reward, Weedtrine)
• Inhibits photosynthesis & destroys cell membranes • Binds to suspended sediment – not for use in turbid waters
Both can cause quick kill and potential dissolved oxygen problems
Aquatic Herbicides Broad spectrum contact herbicides
Carfentrazone (Stingray)
• Use-patterns still being established • Effective on milfoils & some floating plants (Lemna, Pistia,
Eichhornia, Salvinia) but not others (Landoltia punctata, dotted duckweed)
• Single applications not effective on plants with high nodal regeneration capacity (Ludwigia, Hydrocotyle)
• Irrigation restrictions 1-14 days (depending on treatment area)
Flumioxazin (Clipper)
• Watermeal, duckweed, milfoil, hydrilla Kill by cell membrane disruption (Protox inhibitors – chl biosynthesis)
Quick kill in terrestrial settings, slower with aquatics
Aquatic Herbicides Selective systemic herbicides
2,4-D (AquaKleen, Navigate)
• Granular formulation contains butoxy-ethyl-ester and should not be used in water with T&E salmonids
Triclopyr-TEA (Renovate)
• Also commonly used on purple loosestrife • Liquid and granular
Auxin mimic, plant growth regulator Selective for dicots (e.g., milfoils, ludwigia, water
chestnut)
Aquatic Herbicides “Selective” systemic herbicides
Fluridone (Avast, Sonar)
Selective for Eurasian watermilfoil when contact time and dose can be maintained (long contact time at a low concentration)
Low toxicity, but requires long contact time (45-80 days), carotenoid pigment inhibitor
Non-selective at high application rates Liquid and various pellet formulations
Acts on carotenoid biosynthesis pathway
Aquatic Herbicides Selective systemic herbicides
Penoxsulam (Galleon)
• Inhibits plant-specific enzyme (acetolactate synthase inhibitor – branched chain amino acid inhibition)
• Emergent, floating or submersed weed control • Slow-acting; exposure times for submersed treatments similar to
Fluridone • Irrigation restrictions: Do NOT apply to water to be used for irrigation
of greenhouse or nursery plants or hydroponics • Optimum use patterns still being established
Aquatic Herbicides Broad spectrum systemic herbicides
Glyphosate (Rodeo, AquaMaster)
• Deactivated by sediments • Not effective on submersed weeds • Minimal restrictions on irrigation & potable water • Inhibits amino acid and hormone production by blocking shikimic acid
pathway
Imazapyr (Habitat)
• Inhibits plant-specific enzyme (ALS-inhibitor) • Slow-acting • Moderate residual soil activity
Effective for control of floating and emergent weeds with extensive rhizome/root systems (Phragmites, Typha)
Aquatic Herbicides Broad spectrum systemic herbicides
Fluridone (Sonar)
• Broad spectrum at high application rates
Imazamox (Clearcast)
• Similar use patterns to Imazapyr (ALS-inhibitor) + some extended biomass reduction with submersed plants (hydrilla)
• Slow-acting (impacts in 60-120 days) • Irrigation restrictions vary (still/moving water, depth)
Aquatic Herbicides Selective Contact Herbicides
• Various copper formulations (copper sulfate & chelated
copper compounds)
• Cu is persistent in the environment
• Peroxygen granular (GreenClean® & Phycomycin®)
• Relatively new algaecides • Non-copper based (sodium carbonate peroxyhydrate)
Primarily algaecides Cu is problematic due to effects on salmonid olfaction
Note: These tables are meant only as guidelines. Some herbicides carry specific warnings regarding
toxicity to fish, irrigation water, etc. Please read, understand, and follow all label instructions!
Applications should be made by a certified applicator in accordance with all state and federal regulations.
Source:Whetstone and Heaton. 2013. South Carolina Pest Management Handbook for Field Crops
Note: These tables are meant only as guidelines. Some herbicides carry specific warnings regarding
toxicity to fish, irrigation water, etc. Please read, understand, and follow all label instructions!
Applications should be made by a certified applicator in accordance with all state and federal regulations.
Source:Whetstone and Heaton. 2013. South Carolina Pest Management Handbook for Field Crops
Things to consider • The label! • Perceptions / community • Movement of propagules • Implications of no treatment • Herbicide resistance • NPDES requirements addressed by OR DEQ’s:
• Pesticide General Permit (2300-A): discharge in, over or near surface water
• General Permit for Pesticide Use in Irrigation Systems (2000-J)
Dreissenid Mussels Dreissena polymorpha (zebra mussel)
D. rostriformis bugensis (quagga mussel)
Small, epifaunal, freshwater bivalves
Dreissenid Mussles
Rapid growth (15-20 mm/yr) Prolific reproducers (40K – 1 M eggs/yr) Form dense colonies (200,000+/m2) $0.5 Billion impact if introduced in Columbia Basin
Dreissenid Mussels
Watercraft Inspection Stations
Set up for mussels but find more aquatic weeds than anything else
Crayfish • Signal native to OR and WA
• Invaders can impact benthic community, macrophyte abundance, and aquatic foodwebs
Ringed Rusty Red Swamp Signal Northern
Orcon- Orcon- Procamb- Pacifast- Orconectes
ectes ectes arus acus virilis
neglectus rusticus clarkii leniusculus
Potamopyrgus antipodarum New Zealand Mudsnail
• Small (<5 mm) primarily freshwater snail
• Herbivorous scrapers, grazers
• Can develop very high densities (400k/m2 in Columbia R)
• Density-dependent impacts
– Consume primary production/compete with native gastropods, grazers, and detritivors
• Management
– Prevention
– Gear cleaning
Photo by D.L. Gustafson
