Exotic Grasses in Our ForestsExotic Grasses in Our Forests

Art GoverArt Gover

Penn State PENNDOT Roadside Research ProjectPenn State PENNDOT Roadside Research Project

Department of HorticultureDepartment of Horticulture

ResourcesResources

• http://rvm.cas.psu.eduhttp://rvm.cas.psu.edu– annual research reportsannual research reports

– training Powerpointstraining Powerpoints

– publicationspublications• factsheets• applicator training materials

Use and Characteristics of Herbicides for Non-crop Weed Control - 42 pages, 132 K

Weed Management Weed Management BasicsBasics

• Bigger Picture:Bigger Picture:–Symptoms vs CauseSymptoms vs Cause

• Broad Based ApproachBroad Based Approach– Integrated Pest ManagementIntegrated Pest Management

–Prevention & curePrevention & cure

Weed Management Weed Management BasicsBasics

• Strategic PlanStrategic Plan–Prioritize objectivesPrioritize objectives

–Optimize finite resourcesOptimize finite resources

–Ongoing evaluation of results and Ongoing evaluation of results and objectivesobjectives

Japanese stiltgrassJapanese stiltgrass(Microstegium vimineum)(Microstegium vimineum)

• Annual grassAnnual grass

• Shade tolerantShade tolerant

• Germination Germination begins mid-begins mid-March/mid-AprilMarch/mid-April

• Seedhead late-Seedhead late-August/late-August/late-SeptemberSeptember

Stiltgrass ManagementStiltgrass Management

• Prevent seed setPrevent seed set

• Consider seedbank as perennialConsider seedbank as perennial–Once present, control is multi-year Once present, control is multi-year

(ongoing)(ongoing)

• Think '5 Year Plan'Think '5 Year Plan'

PreventionPrevention

• Sanitation - don't move Sanitation - don't move seed/stems to uninfested areasseed/stems to uninfested areas

• Establish alternate groundcover Establish alternate groundcover (where light permits)(where light permits)–RoadsidesRoadsides

–Heavily used trails, trailheadsHeavily used trails, trailheads

Controlling StiltgrassControlling Stiltgrass

• MechanicalMechanical–Mow/pull Mow/pull late summerlate summer (before seed (before seed

set)set)

–Mow lowMow low

–String-trimming on 8/6/02 in Phila. String-trimming on 8/6/02 in Phila. Provided 93% controlProvided 93% control

Stiltgrass ControlStiltgrass Control

• HerbicidesHerbicides–Preventive (preemergence)Preventive (preemergence)

–Curative (postemergence)Curative (postemergence)

• Labeling Labeling –Herbicide use is governed by SITE, Herbicide use is governed by SITE,

not target speciesnot target species

–Stiltgrass does not have to be listed Stiltgrass does not have to be listed on the label to legally useon the label to legally use

Choosing an HerbicideChoosing an Herbicide

• Stiltgrass growth stageStiltgrass growth stage

• SiteSite

• Desirable speciesDesirable species

• EquipmentEquipment

Herbicide CategoriesHerbicide Categories

Preemergence - Preemergence - applied to soil, applied to soil, prevents establishment from seedprevents establishment from seed

Non-selective, contact - Non-selective, contact - 'burndown''burndown'

Non-selective, systemic - Non-selective, systemic - injures all injures all vegetation, moves through plantvegetation, moves through plant

Selective (graminicides) - Selective (graminicides) - injure only injure only grassesgrasses

PreemergencePreemergence

• • Used to control annual weeds in turf Used to control annual weeds in turf and ornamental bedsand ornamental beds

• • MustMust be applied before germination be applied before germination

• • Will not control emerged stiltgrassWill not control emerged stiltgrass

• • Will not injure established plantsWill not injure established plants

• • Similar to Similar to PreenPreen

PreemergencePreemergence

• • pendimethalinpendimethalin - Pendulum - Pendulum

• • oryzalinoryzalin - Oryzalin T/O - Oryzalin T/O

• • prodiamineprodiamine - Endurance - Endurance

• • trifluralintrifluralin - Treflan - Treflan

• • oxyfluorfenoxyfluorfen - Goal 2XL - Goal 2XL

Non-selective, ContactNon-selective, Contact

• Only affects emerged plantsOnly affects emerged plants

• Affects contacted plant partsAffects contacted plant parts

• Rapid symptoms - 2 to 5 daysRapid symptoms - 2 to 5 days

• Perennials will regrowPerennials will regrow

• Most effective on small plantsMost effective on small plants

Non-selective, ContactNon-selective, Contact

• glufosinateglufosinate - Finale, Derringer - Finale, Derringer

• diquatdiquat - Reward - Reward

Non-selective, systemicNon-selective, systemic

• • Plants must be emergedPlants must be emerged

• • Translocates throughout plantTranslocates throughout plant

• • All contacted plants affectedAll contacted plants affected

• • Low rates (16 to 32 oz/ac) kill Low rates (16 to 32 oz/ac) kill stiltgrass, leave perennialsstiltgrass, leave perennials

• • No soil activityNo soil activity

Non-selective, systemicNon-selective, systemic

• • glyphosateglyphosate

• • available in terrestrial and available in terrestrial and aquatic labelsaquatic labels

Selective (Graminicides)Selective (Graminicides)

• • Plants must be emergedPlants must be emerged

• • Affect only grasses - not sedges, Affect only grasses - not sedges, rushes, dicotsrushes, dicots

• • Smaller, annual grasses most Smaller, annual grasses most sensitivesensitive

Selective (Graminicides)Selective (Graminicides)

• quizalofop-Pquizalofop-P - Assure II - Assure II

• fluazifop-Pfluazifop-P - Fusilade II - Fusilade II

• sethoxydimsethoxydim - Vantage - Vantage

• clethodimclethodim - Envoy - Envoy

• fenoxaprop-Pfenoxaprop-P - Acclaim Extra - Acclaim Extra

LeersiaLeersia preserved, preserved,Assure II, 4 oz/acAssure II, 4 oz/ac

PlateauPlateau

• • Low use rates, 2 to 8 oz/acLow use rates, 2 to 8 oz/ac

• • Very effective preemergence, Very effective preemergence, fair-to-good postemergencefair-to-good postemergence

• • JourneyJourney is premix of Plateau plus is premix of Plateau plus glyphosate (8 oz Journey = 3 oz glyphosate (8 oz Journey = 3 oz Plateau + 4 oz RoundUp)Plateau + 4 oz RoundUp)

Systemic, ResidualSystemic, Residual

• PRE and POST activityPRE and POST activity

• Selectivity determined by rate, Selectivity determined by rate, timing, and applicationtiming, and application

Systemic, ResidualSystemic, Residual

• sulfometuronsulfometuron - Oust XP - Oust XP– 0.5 to 1 oz/ac0.5 to 1 oz/ac

• imazapyrimazapyr - Arsenal - Arsenal– ? - 8 oz/ac? - 8 oz/ac

• imazapicimazapic - Plateau, Journey - Plateau, Journey– 4 oz/ac Plateau4 oz/ac Plateau

– 8 - 12 oz/ac Journey8 - 12 oz/ac Journey

Stiltgrass - annual grassStiltgrass - annual grass

FebFeb MarMar AprApr MayMay JunJun JulJul AugAug SepSep OctOct

germinationgermination seed ripeningseed ripening

vegetative growthvegetative growth

Stiltgrass - annual grassStiltgrass - annual grass

FebFeb MarMar AprApr MayMay JunJun JulJul AugAug SepSep OctOct

PRE - pendimethalin, Endurance, oryzalin, trifluralinPRE - pendimethalin, Endurance, oryzalin, trifluralin

PRE/POST - Plateau, Journey, Oust, ArsenalPRE/POST - Plateau, Journey, Oust, Arsenal

POST - glyphosate, Finale, Assure IIPOST - glyphosate, Finale, Assure II

germinationgermination seed ripeningseed ripening

vegetative growthvegetative growth

PRE/EARLY POST - Goal 2XLPRE/EARLY POST - Goal 2XL

MowingMowing

JohnsongrassJohnsongrass((Sorghum halepenseSorghum halepense))

• perennial, C4 (warm season)perennial, C4 (warm season)

• introduced 19th century, forageintroduced 19th century, forage

• stout rhizomesstout rhizomes

• Noxious weed in PA, MD, OH, WVNoxious weed in PA, MD, OH, WV

• full sunfull sun

David J. Moorhead, Univ. of GeorgiaDavid J. Moorhead, Univ. of Georgia

Bonnie Harper-Lore, USDOT-FHWABonnie Harper-Lore, USDOT-FHWA

Barry Fitzgerald, USDA-ARSBarry Fitzgerald, USDA-ARS

Virginia Tech Weed Identification GuideVirginia Tech Weed Identification Guide

Johnsongrass rhizomesJohnsongrass rhizomes

Nonnative Invasive Plants of Nonnative Invasive Plants of Southern ForestsSouthern Forests

• GrassesGrasses

– giant reed (giant reed (Arundo donaxArundo donax))

– tall fescue (tall fescue (Festuca arundinaceaFestuca arundinacea))

– Cogongrass (Cogongrass (Imperata cylindricaImperata cylindrica))

– Nepalese browntop [stiltgrass] Nepalese browntop [stiltgrass] ((Microstegium vimineumMicrostegium vimineum))

– Chinese silvergrass (Chinese silvergrass (Miscanthus Miscanthus sinensissinensis))

– bamboos (bamboos (Phyllostachys, BambusaPhyllostachys, Bambusa))

Johnsongrass ControlJohnsongrass Control

• June, prior to seed ripeningJune, prior to seed ripening

• HerbicidesHerbicides– imazapyrimazapyr

– sulfometuronsulfometuron

– glyphosateglyphosate

– imazapicimazapic

– imazapic + glyphosateimazapic + glyphosate

Johnsongrass - perennial grassJohnsongrass - perennial grass

FebFeb MarMar AprApr MayMay JunJun JulJul AugAug SepSep OctOct

seed germseed germ

rhizome productionrhizome productionrhizome initiationrhizome initiation

floweringflowering

Johnsongrass - perennial grassJohnsongrass - perennial grass

FebFeb MarMar AprApr MayMay JunJun JulJul AugAug SepSep OctOct

seed germseed germ

rhizome productionrhizome productionrhizome initiationrhizome initiation

floweringflowering

Early POST: graminicidesEarly POST: graminicides

Pre seed-set: glyphosate, Oust, ArsenalPre seed-set: glyphosate, Oust, Arsenal