TorpedograssTorpedograss Panicum repens Panicum repens (L.) Poaceae(L.) Poaceae

BiologyBiology• Native to Africa and or AsiaNative to Africa and or Asia

• Introduced into Florida in late 1800’s as a Introduced into Florida in late 1800’s as a wetland forage grasswetland forage grass

• Perennial, spreads through stolons and Perennial, spreads through stolons and rhizomesrhizomes

• Named for sharply pointed or ‘torpedo-Named for sharply pointed or ‘torpedo-like’ growing tipslike’ growing tips

BackgroundBackgroundEconomic UsesEconomic Uses

• Cultivated as Cultivated as wetland foragewetland forage

• Fast growth and Fast growth and high productivityhigh productivity

• Readily grazed by Readily grazed by cattlecattle

DistributionDistribution• Found throughout much of north, central Found throughout much of north, central

and south Floridaand south Florida

• Commonly found along waterways Commonly found along waterways including canals, irrigation/drainage including canals, irrigation/drainage ditches and low, wet areasditches and low, wet areas

• Over 7000 acres in Lake OkeechobeeOver 7000 acres in Lake Okeechobee

Torpedograss Distribution in FloridaTorpedograss Distribution in Florida

ImpactsImpacts• Category 1 invasive species (FLEPPC)Category 1 invasive species (FLEPPC)

– Very aggressive spread into undisturbed Very aggressive spread into undisturbed sites, over 70% of public waters are infestedsites, over 70% of public waters are infested

• Strong competitor, forms large floating Strong competitor, forms large floating mats, impeding water flow and navigation mats, impeding water flow and navigation and recreationand recreation

• Displaces native species – flora & faunaDisplaces native species – flora & fauna

• Also a major problem in citrus and turfAlso a major problem in citrus and turf

IdentificationIdentification

Mature PlantMature Plant• Perennial grass, Perennial grass,

roots on shore and roots on shore and will extend several will extend several feet out into feet out into shallow watershallow water

• Will grow up thru Will grow up thru the water columnthe water column

• Forms dense Forms dense monoculture along monoculture along shoreline of lakes shoreline of lakes and pondsand ponds

LeavesLeaves• Leaf blades are 2 to Leaf blades are 2 to

4 inches long, ¼ 4 inches long, ¼ inch wide, stiff and inch wide, stiff and foldedfolded

• Bluish green colorBluish green color

• Hairy on upper leaf Hairy on upper leaf surfacesurface

RhizomeRhizome• Rhizomes arise from Rhizomes arise from

swollen crown tissue swollen crown tissue (knuckles)(knuckles)

• Rhizomes are very Rhizomes are very extensive, can extensive, can comprise over 90% of comprise over 90% of total plant biomasstotal plant biomass

• Sharp, torpedo-like Sharp, torpedo-like tipstips

PaniclePanicle• Up to 9 inches long, Up to 9 inches long,

numerous branchesnumerous branches

• Reported poor seed Reported poor seed viabilityviability

ManagementManagementPreventativePreventative

CulturalCultural

MechanicalMechanical

BiologicalBiological

ChemicalChemical

PreventativePreventative1.1. Limit planting as a forageLimit planting as a forage

2.2. Remove existing plants, including Remove existing plants, including stolons and rhizomes before seeds stolons and rhizomes before seeds are producedare produced

3.3. Prevent movement of plant material Prevent movement of plant material into areas not infested with into areas not infested with torpedograsstorpedograss

CulturalCultural1.1. Cattle grazing will often keep in Cattle grazing will often keep in

check, but to a limited extentcheck, but to a limited extent

2.2. Programs to educate farmers and Programs to educate farmers and ranches about the problems ranches about the problems associated with torpedograss and associated with torpedograss and proper identificationproper identification

BiologicalBiological1.1. There are no known biological control There are no known biological control

agents available for torpedograss agents available for torpedograss management (with the exception of management (with the exception of grazing) in Florida or the southeastern grazing) in Florida or the southeastern U.S.U.S.

MechanicalMechanical1.1. Small infestations can be removed Small infestations can be removed

with repeated, aggressive tillagewith repeated, aggressive tillage Limited to non-flooded sitesLimited to non-flooded sites

2.2. Burning effective in removing above Burning effective in removing above ground biomass, may enhance ground biomass, may enhance chemical control measureschemical control measures

ChemicalChemical1.1. Broadcast applications for large areasBroadcast applications for large areas

Glyphosate at 2 to 4 lbs-ai/AGlyphosate at 2 to 4 lbs-ai/A Imazapyr at 0.5 to 1.0 lbs-ai/AImazapyr at 0.5 to 1.0 lbs-ai/A

2.2. Spot treatment for smaller areasSpot treatment for smaller areas Glyphosate – 2 to 3% solutionGlyphosate – 2 to 3% solution Imazapyr – 0.5 to 1% solutionImazapyr – 0.5 to 1% solution

3.3. Use surfactant at 0.25%Use surfactant at 0.25%

4.4. Adhere to irrigation restrictions for imazapyr, Adhere to irrigation restrictions for imazapyr, may cause off-target damagemay cause off-target damage

Useful LinksUseful Links• Floridata Homepage: http://

www.floridata.com/main_fr.cfm?state=Welcome&viewsrc=welcome.htm

• University of Florida Center for Aquatic and Invasive Plants: http://aquat1.ifas.ufl.edu/welcome.html

• University of Florida’s Cooperative Extension Electronic Data Information Source: http://edis.ifas.ufl.edu/index.html

Literature CitedLiterature CitedLangeland, K.A. and K. Craddock Burks. Langeland, K.A. and K. Craddock Burks. 1998. Identification and Biology of Non-1998. Identification and Biology of Non-Native Plants in Florida's Natural Areas. Native Plants in Florida's Natural Areas. IFAS Publication SP 257. University of IFAS Publication SP 257. University of Florida, Gainesville. 165 ppFlorida, Gainesville. 165 pp