““Salvinia molestaSalvinia molesta. . Infestation in the Infestation in the Lower Colorado Lower Colorado

River.”River.”Presents: Oscar H. Torres U.Presents: Oscar H. Torres U.University of ArizonaUniversity of Arizona

Department of Soil, Water and Department of Soil, Water and Environmental Science.Environmental Science.

Aquatic Plants Course, SWES 525.Aquatic Plants Course, SWES 525.

Antecedents.Antecedents.

Mitchell (Giant salvinia).Mitchell (Giant salvinia). Brazilian native, free floating aquatic fern.Brazilian native, free floating aquatic fern. Reproduces by vegetative fragmentation.Reproduces by vegetative fragmentation.

HistoryHistory

1999 USFWS discovered 1999 USFWS discovered S. molestaS. molesta within the Cibola National Wildlife within the Cibola National Wildlife Refuge.Refuge.

Other reports as South as Yuma, AZ.Other reports as South as Yuma, AZ.

Origin: Irrigation outfall drain (Palo Origin: Irrigation outfall drain (Palo Verde Irrigation District, [PVID]).Verde Irrigation District, [PVID]).

Adverse effectsAdverse effects

Blocks water system’s intakes and Blocks water system’s intakes and outlets.outlets.

Ecology & Economy:Ecology & Economy:

Limiting free water space Limiting free water space (Recreation). (Recreation).

Usurping Usurping in situin situ vegetation. vegetation.

Increasing anoxic conditions Increasing anoxic conditions (Fishery).(Fishery).

Infested SitesInfested Sites

Lower Colorado River Giant Lower Colorado River Giant Salvinia Task ForceSalvinia Task Force

Bureau of Reclamation.Bureau of Reclamation. Bureau of Land Management.Bureau of Land Management. Fish and Wildlife Service.Fish and Wildlife Service. Department of Agriculture.Department of Agriculture. PVID.PVID. Other local, State, and Mexican Other local, State, and Mexican

Agencies.Agencies.

ObjectiveObjective Eradicating or controlling Eradicating or controlling S. molestaS. molesta

along PVID and Lower Colorado River along PVID and Lower Colorado River (LCR).(LCR).

Integral Action Plan Integral Action Plan Physical control.Physical control.Chemical spray applications.Chemical spray applications.Biological control.Biological control.Public information.Public information.

Physical Removal (PR).Physical Removal (PR).

-Nets.-Nets. -Excavation.-Excavation. -Booms.-Booms. -Skimmer.-Skimmer.

PRPR

Advantages:Advantages: Non polluting.Non polluting.

Disadvantages:Disadvantages: Expensive and effort consuming.Expensive and effort consuming. Complete removal was not Complete removal was not

usually achieved (native flora).usually achieved (native flora).

Chemical applications Chemical applications (CA).(CA).

Chelated Copper 10% to 15% Chelated Copper 10% to 15% Solution. (Clearigate, Komeem).Solution. (Clearigate, Komeem).

Diquat-Glyphosate Mixture 15% Diquat-Glyphosate Mixture 15% diquat-5% glyphosate Solution, and diquat-5% glyphosate Solution, and Surfactant.Surfactant.

Diquat alone. Diquat alone.

CA.CA.

Fluridone.Fluridone. Diquat dibromide and Surfactant.Diquat dibromide and Surfactant. Glyphosate and Surfactant.Glyphosate and Surfactant.

CACA

CACA

AdvantagesAdvantages Effective on eradicating plants.Effective on eradicating plants.

CA (Disadvantages)CA (Disadvantages)

Could copper levels.Could copper levels. Glyphosate and diquat have { } use Glyphosate and diquat have { } use

in waters with sediments.in waters with sediments. Copper based, { } where fauna Copper based, { } where fauna

resides, & where resides, & where ==COCO33> 50 ppm.> 50 ppm. Non substrate specific.Non substrate specific. Polluting.Polluting. Expensive & Effort consuming.Expensive & Effort consuming.

Biological Control (BC).Biological Control (BC).

Cyrtobagous salviniae Cyrtobagous salviniae weevils.weevils. 2001 USDA approved tests on 2001 USDA approved tests on

biocontrol.biocontrol. 2003 USDA approved release at LCR.2003 USDA approved release at LCR.

BC.BC.

From 2003 to 2005 weevils From 2003 to 2005 weevils controlled salvinia population where controlled salvinia population where applied.applied.

Weevils need + time.Weevils need + time. + investigation to conclude if + investigation to conclude if

weevils are successful in long spans.weevils are successful in long spans.

BCBC

AdvantagesAdvantages Species specific.Species specific. + Effective in stagnant waters.+ Effective in stagnant waters. Inexpensive.Inexpensive.

BCBC

DisadvantagesDisadvantages - Ineffective during winter (~5- Ineffective during winter (~5° C).° C). - Ineffective on waters.- Ineffective on waters.

Public Education and Public Education and OutreachOutreach

Throughout 2006Throughout 2006

August: Biocontrol monitoring August: Biocontrol monitoring continues along LCR: 3000 continues along LCR: 3000 weevils/mweevils/m22..

October: Diquat & glyphosate October: Diquat & glyphosate application:application:

@ Estes & Browns drain (salvinia @ Estes & Browns drain (salvinia present).present).

Spraying as salvinia disappeared.Spraying as salvinia disappeared.

Conclusions & Conclusions & propositionspropositions

The integrated approach solution has The integrated approach solution has reached the results.reached the results.

Conclusions & Conclusions & propositionspropositions

BC: research on larvae. BC: research on larvae. 3 years of continual 3 years of continual evaluation. evaluation.

Reclamation procedures: successful in Reclamation procedures: successful in stagnant watersstagnant waters

Conclusions and Conclusions and proposalsproposals

Perhaps Perhaps curbed salvinia: natural curbed salvinia: natural conditionsconditions

limited nutrientslimited nutrients

turbulenceturbulence

temperaturetemperature Removal of 90-95% @ PVID.Removal of 90-95% @ PVID. Removal on river: total (natural Removal on river: total (natural

conditions?)conditions?)