Definitions

• Control – prevention of spread by removing fruits and limiting vegetative spread

• Eradicate – to completely remove a species from a location

Subjects

• Approaches to control– Mechanical– Herbicides

• Common species

Manual and Mechanical• Hand pulling -can use volunteers

-good for small infestations-can have low ecological impact-need to keep equipment clean-best for annuals or shallow rooted perennials

Manual and Mechanical•Tillage/hoeing•Mowing, brush cutting, weed eating

–Best for species that don’t coppice–“controls” – does not eradicate except through repeated use•Girdling – remove cambium (do not use on coppicing species)•Mulching – bark, chips, hay, hogfuel, cardboard, carpet•Flooding/drawdowns•Fire

Manual or Mechanical•Soil solarization – clear or black plastic

- kills tissue if around 113-131 degrees F- soil should be moist- can reduce weed populations for more than a year- not as good for rhizomatous species

Waipuna

• Hot foam containing sugar extracts from corn and coconut (originally hot water/steam) – not an herbicide

• Expensive

Grazing• Can control or encourage invasive

plants• Can use cattle, goats, sheep, geese,

chickens, ducks, etc. • Need to fence or pen them in• Make take several years

Herbicides• Salts used in ancient times• 1902- Army Corps of Engineers,

sodium arsenite• 1941 2,4,D synthesized – growth

regulator• 1944 – 2,4,D used on broadleafs

Mechanisms - Herbicides• Inhibit respiration

–Arsenic compounds–Metallo-organics (also based on arsenics)–Phenols

Mechanisms - Herbicides• Inhibit plant growth – hormone

disruptors-absisic acid – no herbicides-cytokinens – no herbicides-Gibberellins – affects plant height, bud

dormancy, seed germination – more of a growth regulator than herbicide

Mechanisms - HerbicidesHormones, cont. • Ethylene – no herbicides• Auxins – 2,4,D (Weed B Gone) – causes

excess cell division and overgrowth, good on broadleaf weeds, non-persisting, low mammalian toxicity – BUT…2,4,5,T – better for woody plants >> +dioxin = Agent Orange

Mechanisms - Herbicides• Inhibitors of biosynthetic processes- Cell division – “pre-emergent”- Nucleic acid or protein synthesis

inhibitors – “pre-emergent”- Glyphosate – non-selective contact

herbicide, interrupts the shikimate pathway – amino acid production pathway not found in animals – “post-emergent”

Considerations• 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• Basal bark• Cut stump• Injected into cambium• Soil – pre-emergent

http://tncweeds.ucdavis.edu/

Reed Canary GrassPhalaris arundinacea

• Rhizomatous grass• Mow 5X +/yr• Mulches (+ cardboard)• Glyphosate (2%)• Shading with plantings

English IvyHedera helix

• Fast-growing ground cover• Remove vertical vines first• Pull and wad vines on ground• Can use string trimmer

followed by glyphosateor 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