definitions control – prevention of spread by removing fruits and limiting vegetative spread...
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Definitions
• Control – prevention of spread by removing fruits and limiting vegetative spread
• Eradicate – to completely remove a species from a location
Topics
•Approaches to control
•Methods of control– Mechanical– Chemical (types of herbicides, application
methods
•Selected PNW species
Assessing Invasive Species Threats
At the landscape scale it is necessary to take two approaches
simultaneously and iteratively:
By spatial distribution of invaders and
conservation goals(Superlative sites)
By invasive species(Scary species)
Acr
es I
nfe
sted
Eradication simple
Plant absent
Era
dic
atio
n
feas
ible
Era
dic
atio
n u
nli
kely
,
inte
nse
eff
ort
req
uir
ed
Scattered locations
Numerous locations
At or near biological potential
Local control and management only
Weed Increase Over Time and Control Potential
Co
ntr
ol
Co
sts
Public awareness typically begins
Introduction
Time
Detection
Study Conclusions
• Eradication possible if under 1 hectare• 1/3 of infestations between 1 and 100
hectares eradicated• ¼ of those between 101 and 1000 eradicated• Cost goes up greatly with size• SO early detection and rapid response is
essential!!!!!Rejmanek and Pitcairn 2002
Bradley Method
• Work in the least invaded areas first, working towards invaded areas
• Make minimal disturbance – mulch if you must disturb the soil
• Let native plant regeneration and your maintenance ability dictate the rate of weed removal – never overclear
Manual and Mechanical
• Hand pulling -can use volunteers
-good for small infestations-can have low ecological impact-need to keep equipment clean-minimize disturbance! Mulch!-best for annuals or shallow rooted perennials
Manual and Mechanical
•Tillage/hoeing
•Mowing, brush cutting–Best for species that don’t coppice
–“controls” – does not eradicate except through repeated use
•Girdling – remove cambium (do not use on coppicing species, beware creating a hazard tree!)
•May need to remove stem fragments
Manual or MechanicalSoil solarization
- kills tissue if around 113-131 degrees Fclear plastic more likely to heat to this
- soil should be moist- not as good for rhizomatous species- may alter soil biology and chemistry
Steam or Hot Water
• Hot water breaksdown theepidermis, theplant becomes dehydrated
• Waipuna now promotingfoam – coconut syrup andwater
Infrared Technology
• Heats to 1000oC
• Bursts cells – stops
photosynthesis
• Not good for deeply
rooted species
Grazing
• Can eliminate or encourage invasive plants
• Can use cattle, goats, sheep, geese, chickens, ducks, etc.
• Goats eat broadest list of weeds• 500 sheep = 4/5 acres/day• Need to fence or pen them in• May disturb soil, may pass
seeds
Mechanisms - Herbicides
• Inhibit respiration–Arsenic compounds–Metallo-organics (also based on arsenics)–Phenols
• Can be very toxic to mammals
Mechanisms - Herbicides
• Auxins – 2,4,D – causes excess cell division and overgrowth, good on broadleaf weeds, non-persisting, low mammalian toxicity 2,4,5,T – better for woody plants >> has dioxin = Agent Orange, causes cancer
• Common now: Clopyralid (persists in compost), picloram, triclopyr (Garlon, Brush B Gone)
Mechanisms - Herbicides
• Inhibitors of biosynthetic processes- Cell division – “pre-emergent”- Nucleic acid or protein synthesis inhibitors
– “pre-emergent”- Glyphosate – non-selective contact
herbicide, interrupts an amino acid production pathway not found in animals – “post-emergent,” Rodeo® used for aquatics
Adjuvants
• Added to facilitate mixing, effectiveness, or application of herbicide
• “Surfactants,” “spreader-sticker”
• Usually chemically active, but may be termed “inert”
• Sometimes included, if not, research to find recommended one for what you use
Considerations using Herbicides
• Non-target species
• Use best management practices for handling concentrates
• Follow ALL laws
• Must post treated areas
• Carefully assess site conditions, including weather
• Likely cannot use volunteers
Methods of Application
• Foliar – spot, boom
• More herbicide
delivered to
non-targets
• May need a
surfactant
Methods of Application
• Basal bark
• 6” band 1’ up stem
• Must mix with
low ester oil
• Best for smaller
shrubs
Methods of Application
• “Hack and squirt”
• Cut every 2 in or
so of stem
• Good for small trees
4-5” dia
• Creates hazard trees!
Methods of Application
• Cut stump “Cut and dab”• Only need to
treat the cambium• Apply immediately
after cutting• Paintsticks handy• May need to reapply• Not as good in early spring
Methods of Application
• Injected into cambium
• Can be good for some
herbaceous as well as
woody
• Little human contact with
herbicide
• Buy appropriate injectors
Reed Canary GrassPhalaris arundinacea
• Rhizomatous grass
• Mow 5X +/yr
• Mulches (+ cardboard)
• Glyphosate (2%)
• Shading with plantings
Atlantic/English Ivies
Hedera hibernica ‘HibernicaH. helix ‘Pittsburg’
H. helix ‘Baltica’
H. helix ‘Star’
Ivies
• Fast-growing ground cover
• Remove vertical vines first
• Pull and wad vines on ground
• Can use string trimmer followed by glyphosate or triclopyr
Japanese KnotweedFallopia japonica
• Strongly rhizomatous shrub• Very hard to kill• 2X/month mowing for
3 years• Injection – 5 ml of
100% glyphosate• Triclopyr or glyphosate
Himalayan blackberryRubus armeniacus
• Repeated mowing• Digging• Cut stump, treat
with triclopyr or
triclopyr + 2,4 - D
Iris pseudacorusYellow flag iris
• Freshwater aquatic but
drought resistant
• Seeds and rhizomes
• Dense thickets along shore
• Dig by hand or machine
• Cutting + glyphosate
Scotch broom Cytisus scoparius
• Prairies, grasslands
• Nitrogen-fixer
• Pull or cut stump
• Seeds long lived
herb robert, stinky bob Geranium robertianum
• Herbaceous annual• Spreads by explosive seeds• May be allelopathic• Easy to pull• Seeds live 5+ yrs
hedge bindweed Calystegium sepium
• Older name Convolvulus sepium• Fleshy rhizomes 1-2 ft deep• Blankets shrubs• Likes wetter soils• Responds to triclopyr –
pull as much as possible,
mulch, then spray as vines
grow
Resources
• TNC Weed Control Handbook
http://tncweeds.ucdavis.edu/handbook.html
• TNC “Stewardship Abstracts”
http://tncweeds.ucdavis.edu/esadocs.html
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