Range of Invasion • Natural ecosystem disrupted by exotic invasive species • Open rangeland • Forested ecosystems • Swamps, wetlands • Aquatic situations (lakes/ponds, rivers, irrigation canals)
Why an Issue? • Exotic species are highly adapted to diverse ecological areas • High reproductive capacity • No natural enemies (disease, insects, etc.) • Biological desert
Management • Primary method is PREVENTION!! • Invasive assessment, prediction models • Mechanical • Effective but not practical on large areas • Generally does not eradicate • Also includes burn, flood, mowing, etc. • Biological control is IDEAL, but…………. • Chemical – the big issue is………..?
Selectivity • In crops you are trying to control all species except the crop • In invasive plant control you are trying to control one species and not harm everything else • Integrated approach is the key, but a major decision has to be made first
To Eradicate or not to Eradicate • Eradication • high degree of coordination & monitoring • high $$, quarantines • eliminate all individuals, propagules, etc. that could regenerate a population • continually monitor to ensure eradication • Maintenance control is that situation where you constantlymonitor the populations and control when levels reach a certain threshold, which is generally very low
Caulerpa • $ 4 million • 5 years
Nascent Foci Approach • Start on the outlying populations first and work into the center • Accurate survey of infestation and data on the range of spread (mechanism of dispersal) • Continually monitor over the area already covered
Revegetation • Planting back a desirable species that will provide ecological stability and possibly hinder/block reinfestation of invasive species • When and how much invasive control do you need? • Possibility of selective control?
Impacts • Category 1 invasive species (FLEPPC) • Ability to spread into undisturbed sites • Extremely fast growth > 8 inches/day • Smothers trees and native understory species • Spreads rapidly through massive production of bulbils
Mature Plant • Rapidly climbing, twining herbaceous vine • Vines killed by frost • Regrowth from underground tubers
Leaves and Flowers • Leaves cordate • All leaf veins arise from leaf base • Flowers are inconspicuous, arise from panicles from leaf axils
Bulbils • Aerial tubers, borne in leaf axils • Generally roundish, smooth and gray to brown in color • Primary means of spread
Preventative • Limit planting as an ornamental • Remove existing plants, including resprouts and before bulbils are produced • Avoid spread through contaminated debris, brush or soil • Clean mowers and other brush-cutting equipment
Cultural • Programs to educate homeowners about the problems associated with air potato and proper identification • Remove populations along waterways • Bulbils will float to new areas • Gather bulbils in fall after frost (Gainesville Air Potato Roundup)
Biological • There are no known biological control agents available for air potato management in Florida or the southeastern U.S.
Mechanical • Hand pull young seedlings, including all roots, dig up tubers • Mowing is effective, but must be repeated and may spread bulbils • Burning is not a viable option – fire ladders into canopy of trees
Chemical • Over-the-top applications before bulbil formation, during spring and summer • Thoroughly wet leaves with herbicide • Triclopyr – 2% solution • Glyphosate – 2 to 3% solution • Use surfactant at 0.25% • Retreatment necessary to kill tuber and resprouting bulbils
Biology • Also known as silk tree • Medium-sized tree, 20 - 40 feet tall • Legume plant - capable of fixing nitrogen • Introduced from China to the U.S. in the mid 1700’s
Mature Plant • Small tree – 20 to 40 feet in height • Highly branched, rambling habit • Leaves and flowers in clusters at the end of branches
Mechanical • Hand pull young seedlings, including all roots, repeated pulling for resprouts • Cut tree down at ground level • Girdling is effective for large trees • Cut through bark approximately 6 inches above the ground, encircling tree base • Mowing is effective on small saplings and resprouts, but must be repeated
Chemical - Foliar • Over-the-top applications for seedlings, resprouts and small trees • Thoroughly wet leaves with herbicide • Triclopyr – 2% solution • Glyphosate – 2% solution • Clopyralid - 0.2 to 0.4% solution • Use surfactant at 0.25% • Best results applied July to October
Chemical - Basal • Individual trees, near desirable species • Use 25% triclopyr solution with basal oil • Apply 12 to 15 inches above ground on tree trunk • Wet thoroughly for good control, spray until run-off is noticeable at ground line
Chemical – Cut Stump • Individual trees, near desirable species • Cut trunks/stems horizonally at or near ground level • Apply 25% solution of glyphosate or triclopyr • Cover the outer 20% of the stump • Marker (blue) dye is helpful
Putting It All Together • Control strategies often not known or available • A rule of thumb - glyphosate for most species, triclopyr for broadleaf species and vines • Treat ‘pockets’ of invasive species – isolated; but be sure not to spread the species in the process • Target areas along streams and riverbeds, as those areas provide greater capacity for spread
Spring • Focus first on annual species • Controlled effectively as seedling plants • Retreatment may be necessary in the summer • Final check in the late summer/early fall to kill remaining plants that may set seed • Follow-up the next year or two • The key with annual species is prevention of seed set.
Late Summer/Fall • Perennial species with vegetatively persistent structures, fall treatments are generally most effective • Herbicides translocated to the vegetative propagules and provide longer, more consistent control • If species flower in the fall, be sure to treat prior to seed set
Winter • Target trees during the winter months, especially basal bark treatments • Allows ample time to check later in the summer/early fall for regrowth • Cut stump treatments can be performed anytime, so use the time during the cooler winter months for this activity
Bringing It Together • Set up a grid with various treatment zones, citing problem species in each zone • GPS referencing is particularly helpful • Follow-up will be critical, but you should eventually get to a point where routine maintenance will be all that is necessary.
Impacts • Category I invasive species (FLEPPC) • Disrupts natural plant communities • Shade out desirable species, especially native seedlings and understory plants • Resprouts readily after fire or mechanical removal • Heavy fruit set after 2 years of establishment
Mature Plant • Small upright shrub, up to 6 feet tall • Often grows in large colonies • Shade tolerant, understory species
Seedlings • Seedlings often found encircling a mature plant • Plants will remain in juvenile stage until mature specimen is removed
Leaves • Alternate arrangement, but tight to the main stem • Scalloped margins • Dark, thick, glossy green
Flowers and Fruit • Flowering occurs in spring – small white/pink clusters • Fruit are bright red and hang from the plant • Persist on the plants for several months
Fruit and Seed • Fruit readily consumed by wildlife - birds • Seed viability is very high and germinate in a wide range of soil conditions
Mechanical • Hand pull young seedlings, including all roots, repeated pulling for resprouts • Mowing or clipping/chopping is effective, but must be repeated due to resprouting from rootstocks. However, mowing may not be practical in many areas.
Chemical - Foliar • Over-the-top applications for seedlings and large plants • Thoroughly wet leaves with herbicide • Glyphosate – 2-3% solution plus surfactant at 0.25% to increase herbicide penetration of the waxy leaves • 2,4-D – 2-3% solution is also effective, but only on seedlings or resprouts
Chemical - Foliar • Over-the-top applications for seedlings and large plants • Use 18% triclopyr solution with basal oil or 10% diesel fuel
Impacts • Category II invasive species (FLEPPC) • Limited spread into undisturbed sites • Strong competitor • Readily establishes, high quantity of seed or resprouting • Fixes nitrogen • Competes effectively for sunlight and nutrients
Stems and Bark • Younger stems lime green, covered with lenticels (small pits in bark) • On older stems becomes light brown to grayish • Smooth bark
Leaves • Alternately arranged • Bipinnate compound • 6 to 20 inches long • 20 to 60 leaflets per branch • Leaf arrangement gives mimosa fern-like or feathery appearance
Flowers • Flowering occurs from May to July • Borne in terminal clusters at base of the current year’s twigs • Fragrant, pink in color, frizzy
Fruit and Seed • Flat seed pods, straw-colored, 6 inches long • Pod contains 5 to 10 seeds, light brown oval-shaped • Seed pods persist on the tree throughout winter
Seed • Scarification required for germination • Seed dormancy for many years • Dispersal occurs through water and may occur through wildlife ingestion and excretion