Transcript Exotic Grasses in Our Forests Art Gover Penn State PENNDOT Roadside Research Project Department of Horticulture.

Exotic Grasses in Our Forests
Art Gover
Penn State PENNDOT Roadside Research Project
Department of Horticulture
Resources
• http://rvm.cas.psu.edu
– annual research reports
– training Powerpoints
– publications
• factsheets
• applicator training materials
Use and Characteristics of
Herbicides for Non-crop Weed
Control - 42 pages, 132 K
Weed Management
Basics
• Bigger Picture:
– Symptoms vs Cause
• Broad Based Approach
– Integrated Pest Management
– Prevention & cure
Weed Management
Basics
• Strategic Plan
– Prioritize objectives
– Optimize finite resources
– Ongoing evaluation of results and
objectives
Japanese stiltgrass
(Microstegium vimineum)
• Annual grass
• Shade tolerant
• Germination
begins midMarch/mid-April
• Seedhead lateAugust/lateSeptember
Stiltgrass Management
• Prevent seed set
• Consider seedbank as perennial
– Once present, control is multi-year
(ongoing)
• Think '5 Year Plan'
Prevention
• Sanitation - don't move
seed/stems to uninfested areas
• Establish alternate groundcover
(where light permits)
– Roadsides
– Heavily used trails, trailheads
Controlling Stiltgrass
• Mechanical
– Mow/pull late summer (before seed
set)
– Mow low
– String-trimming on 8/6/02 in Phila.
Provided 93% control
Stiltgrass Control
• Herbicides
– Preventive (preemergence)
– Curative (postemergence)
• Labeling
– Herbicide use is governed by SITE,
not target species
– Stiltgrass does not have to be
listed on the label to legally use
Choosing an Herbicide
• Stiltgrass growth stage
• Site
• Desirable species
• Equipment
Herbicide Categories
Preemergence - applied to soil,
prevents establishment from seed
Non-selective, contact - 'burndown'
Non-selective, systemic - injures all
vegetation, moves through plant
Selective (graminicides) - injure only
grasses
Preemergence
• Used to control annual weeds in turf
and ornamental beds
• Must be applied before germination
• Will not control emerged stiltgrass
• Will not injure established plants
• Similar to Preen
Preemergence
• pendimethalin - Pendulum
• oryzalin - Oryzalin T/O
• prodiamine - Endurance
• trifluralin - Treflan
• oxyfluorfen - Goal 2XL
Non-selective, Contact
• Only affects emerged plants
• Affects contacted plant parts
• Rapid symptoms - 2 to 5 days
• Perennials will regrow
• Most effective on small plants
Non-selective, Contact
• glufosinate - Finale, Derringer
• diquat - Reward
Non-selective, systemic
• Plants must be emerged
• Translocates throughout plant
• All contacted plants affected
• Low rates (16 to 32 oz/ac) kill
stiltgrass, leave perennials
• No soil activity
Non-selective, systemic
• glyphosate
• available in terrestrial and
aquatic labels
Selective (Graminicides)
• Plants must be emerged
• Affect only grasses - not sedges,
rushes, dicots
• Smaller, annual grasses most
sensitive
Selective (Graminicides)
•
quizalofop-P - Assure II
•
fluazifop-P - Fusilade II
•
sethoxydim - Vantage
•
clethodim - Envoy
•
fenoxaprop-P - Acclaim Extra
Leersia preserved,
Assure II, 4 oz/ac
Plateau
• Low use rates, 2 to 8 oz/ac
• Very effective preemergence, fairto-good postemergence
• Journey is premix of Plateau plus
glyphosate (8 oz Journey = 3 oz
Plateau + 4 oz RoundUp)
Systemic, Residual
• PRE and POST activity
• Selectivity determined by rate,
timing, and application
Systemic, Residual
• sulfometuron - Oust XP
– 0.5 to 1 oz/ac
• imazapyr - Arsenal
– ? - 8 oz/ac
• imazapic - Plateau, Journey
– 4 oz/ac Plateau
– 8 - 12 oz/ac Journey
Stiltgrass - annual grass
vegetative growth
germination
Feb
Mar
Apr
May
seed ripening
Jun
Jul
Aug
Sep
Oct
Stiltgrass - annual grass
vegetative growth
germination
Feb
Mar
Apr
May
seed ripening
Jun
Jul
Aug
Sep
Oct
PRE - pendimethalin, Endurance, oryzalin, trifluralin
PRE/EARLY POST - Goal 2XL
PRE/POST - Plateau, Journey, Oust, Arsenal
POST - glyphosate, Finale, Assure II
Mowing
Johnsongrass
(Sorghum halepense)
• perennial, C4 (warm season)
• introduced 19th century, forage
• stout rhizomes
• Noxious weed in PA, MD, OH, WV
• full sun
David J. Moorhead, Univ. of Georgia
Bonnie Harper-Lore, USDOT-FHWA
Barry Fitzgerald, USDA-ARS
Johnsongrass rhizomes
Virginia Tech Weed Identification Guide
Nonnative Invasive Plants of
Southern Forests
• Grasses
– giant reed (Arundo donax)
– tall fescue (Festuca arundinacea)
– Cogongrass (Imperata cylindrica)
– Nepalese browntop [stiltgrass]
(Microstegium vimineum)
– Chinese silvergrass (Miscanthus
sinensis)
– bamboos (Phyllostachys, Bambusa)
Johnsongrass Control
• June, prior to seed ripening
• Herbicides
– imazapyr
– sulfometuron
– glyphosate
– imazapic
– imazapic + glyphosate
Johnsongrass - perennial grass
flowering
rhizome initiation
rhizome production
seed germ
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Johnsongrass - perennial grass
flowering
rhizome initiation
rhizome production
seed germ
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Early POST: graminicides
Pre seed-set: glyphosate, Oust, Arsenal
Oct