Natural Area Weed Management - University of Florida Wedne… · Developed by: Fred Fishel, Ken...
Transcript of Natural Area Weed Management - University of Florida Wedne… · Developed by: Fred Fishel, Ken...
Natural Area Weed Management
Developed by: Fred Fishel, Ken Langeland (retired), Stephen Enloe, and Lyn Gettys
UF/IFAS Agronomy
Modified & presented by: Michelle Atkinson, Environmental Horticulture Agent
Disclaimer
The use of trade names in this presentation is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition.
Study Materials
Applying Pesticides Correctly (SM-1)
Natural Areas Weed Management (SP-295)
https://ifasbooks.ifas.ufl.edu/
1-800-226-1764
Recertification
Every 4 years
CEUs16 NAWM + 4 Core
http://ceupublicsearch.freshfromflorida.com/
Pesticide Applicator Records
Applications of herbicides which carry the DANGER signal word on their labels require applicator records for those who work in natural areas
Florida’s Organo-Auxin Herbicide Rule
Examples: 2,4-D, triclopyr
Regulating and Categorizing of Pest Plants
Florida Noxious Weed List
Identification of Pest Plants
Early detection of new weed infestations is a
key component of integrated
management of pest plants in natural areas
Identification of Pest Plants
Plant Names
Common nameCan be confusing
It is not necessary to know both the scientific names and common names of plants for
certification testing, only the common name
Scientific nameGenus (the first part of the name)
Specific epithet (the second part of the name)
Ferns
Asian sword fern (Nephrolepis multiflora)
Sword fern (Nephrolepiscordifolia)
Herbaceous Species
Wetland nightshade (Solanum tampicense)
• Straggly, sprawling plant with prickly stems up to 16’
• Stem prickles are white to tan• Stems sparsely hairy• Leaves alternate with prickles
Herbaceous Species
Tropical soda apple (Solanum viarum)
• Bushy, prickly perennial to 6’• Stems armed with broadbased, straight
or downward pointing prickles• Leaves alternate and also prickly• Fruit green when immature, dull yellow
when ripe
Shrubs
Coral ardisia (Ardisia crenata)
• Evergreen, multi-stemmed shrub to 6’ tall Alternate, dark green waxy leaves with distinct scalloped margin
• White to pink flowers, stalked in clusters in leaf axis
• Bright red, spherical fruit
Shrubs
Shrub verbena (Lantana camara)
• Multi-stemmed, deciduous shrub to 6’• Square stems, bristly hairs, small
prickles• Opposite stalked leaves with blunt-
toothed margins, hairy, up to 6” long• Small multi-colored flowers in stalked,
dense, flat topped clusters
Vines
Air potato (Dioscorea bulbifera)
• Vigorously twining herbaceous vine up to 66+ feet
• Internodes round• Small or absent underground tubers• Aerial, usually round tubers in leaf
axis• Small fragrant flower in leaf axis
Vines
Japanese climbing fern (Lygodium japonicum)
• Fern with climbing, twining fronds to 90’ long
• Fronds are compound, triangular in shape up to8”
• Stems are wiry and green, black or orange forming dense mats
• Leaflets are lobed, stalked, with terminal lobes dissected
Vines
Old World climbing fern (Lygodium microphyllum)
• Fern with dark brown wiry rhizomes
• Climbing twining fronds to 90’• Leaflets usually unlobed, smooth
on undersides, stalked, leaving wiry stalks when detached
Vines
Cat’s claw vine (Dolichandra unguis-cati)
• Sprawling thicket forming shrub• Hairy stems with prickles• Alternate, twice compound leaves• Sensitive to touch• Small mauve to pink flowers (.5” across)• Brown-bristy, segmented, flat pod (3” X .5”)
Vines
Kudzu (Pueraria montana)
• Semi-woody perennial vine, high climbing, trailing to 65’
• Tuberous roots• Rope-like dark, hairy stems to 4” or
more diameter• Leaves alternate, with 3 leaflets, hairy
margins entire or deeply lobed
Grasses
Cogongrass (Imperata cylindrica)
• perennial grass that grows in loose or compact tufts from stout extensive rhizomes with sharp-pointed tips
Trees
Melaleuca (Melaleuca quinquenervia) • Evergreen tree with a slender
crown• Bark soft, whitish, many-layered,
peeling• Leaves alternate, simple,
grayish-green, narrow lance shaped, 4” long
• Smell of camphor when crushed
TreesBrazilian pepper
(Schinus terebinthifolius)
• Shrub or small tree with short trunk• Numerous long, arching, intertwined
branches• Leaves evergreen, alternate,
pinnately compound with 3-11 leaflets, when crushed smell peppery or turpentine
• Bright red spherical drupe
Trees
Chinese tallow (Triadica sebifera)
• Deciduous tree to 52’ with milky sap• Leaves alternate, entire, rhombic to
ovate, 1-2.5” wide• Petioles long and slender with 2
glands at apex
Introduction
Herbicides: chemicals used for killing plants or severely interrupting their normal growth processes
May be charged (polar or ionic) or uncharged (nonpolar)
The chemical makeup of an herbicide’s active ingredient determines its toxicity, solubility, absorption characteristics, behavior in plants,
behavior in soil, environmental fate, and selectivity
Toxicity of Herbicides Used in Natural Areas
Risk = Hazard x Exposure
Risk to wildlife is determined as the product of hazard and exposure
Toxicity of Herbicides Used in Natural Areas
Public HealthTests: acute, subchronic, chronic toxicityRoutes of entry, birth defects, tumors, cancer….etc
Residue tolerances are established at 100 or 1,000 lower than the
herbicide concentration tolerated by test animals
Herbicide SolubilitySalts of triclopyr amine, 2,4-D amine, glyphosate are water soluble
Water-soluble herbicides do not mix with oil, and oil does not mix with water
Absorption of Herbicides by Plants
Absorption: the process by which an herbicide passes from one system into another, e.g., from the soil solution into a plant root cell or from the leaf surface into leaf cells
Foliar Absorption
The cuticle is the first and most important barrier to the absorption of an herbicide on a leaf surface
Foliar Absorption
Surfactants added to spray mixes can help overcome surface tension and aid in uptake of the herbicide
Root Absorption and Behavior in Soils
Adsorption: the process whereby chemicals (including herbicides) are retained on the surfaces of soil particles
Most important factor by which herbicides become unavailable for uptake from soilsHumus is considered the most important soil constituent that affects absorption by plant roots
Stem Absorption
Stem Absorption
Stem Absorption
Terminology
Classify herbicides by following categories: • Pre-emergent vs. post-emergent• Selective vs. nonselective• Contact vs. translocated• Persistent vs. non-persistent• Their modes of action
Terminology
Pre-emergent vs. post-emergent• Root-absorbed herbicide example:
hexazinone• Foliage-absorbed herbicide examples: 2,4-D,
glyphosate• Both root- and foliage-absorbed examples:
aminopyralid, aminocyclopyrachlor, imazapyr
TerminologySelective vs. nonselective
Selective herbicides control only certain types of plants
Nonselective herbicides generally control most plants
2,4-D
Fluazifop-p
What about Glyphosate?
Terminology
Contact vs. translocated• Contact herbicides kill only the parts of the plant
they actually touch• Limitations where long-term weed control is
desired, such as in natural areas• Translocated herbicides are absorbed by roots or
leaves and carried in the plant sap throughout the plant Examples: glyphosate, 2,4-D
Terminology
Persistent vs. non-persistent• Usually reported as the chemical’s half-life• 10-day half-life of 2,4-D• More than 400 days under certain conditions
for aminocyclopyrachlor
Persistence refers to the time that an herbicide remains in the environment
Terminology
Herbicide Modes of Action
The way in which a particular herbicide disrupts a plant process is called its mode of action
Terminology
Act like natural plant growth regulators
Examples: 2,4-D, triclopyr
Auxin growth regulators
Translocate throughout the plant
Herbicide Modes of Action
Terminology
Translocated throughout the plant
May be nonpersistent, such as glyphosate
May be persistent, such as metsulfuron and imazapyr
May take a week to several weeks before symptoms appear
Are used at low rates – ounces per acre
Amino acid inhibitors
Herbicide Modes of Action
Terminology
Block photosynthesis in susceptible plants
Root uptake is the primary route for these herbicides to enter the plant
All persist in the soil and provide residual weed control
Example: hexazinone
Photosynthesis inhibitors
CO2 +
2H2O Chlorophy
ll
CH2O + H2O +
O2X
Herbicide Modes of Action
Factors That Affect Herbicide Activity
Water stress caused by drought conditions can reduce foliar and root uptake of herbicide and translocation
Herbicide Resistance Management
Select and use herbicides correctly
Herbicide Modes of Action
Resistance in General
Resistance can develop when the same pesticide or similar ones with the same mode of action are used repeatedly
Pests don’t change or mutate in response to a pesticide; the population changes
Resistance in General
Biotype: group of organisms within a species that has biological traits not common to the population
Herbicide Resistance Management
Integrated Weed ManagementUtilizing all available control methods:
Mechanical removalBiological controls
Herbicide Resistance Management
Integrated Weed Management
Don’t Be A Vector
Foliar Applications
Broadcast applications are used where damage to non-target vegetation is not a concern
Basal Bark Applications
The herbicide must be in an oil-soluble formulation
(emulsifiable concentrate)
Hack-and-Squirt Applications
Incisions should be angled downward at approximately 45° to hold herbicide in the cut
Herbicide (concentrated or diluted) is applied…
Treatments are specific and total vegetation control is not achieved
Stump Treatments
Herbicide (concentrated or diluted) is sprayed, poured, or painted on the cut surface
Application should be directed towards just inside the bark
where the active vascular tissue is present
Stump Treatments
Best results, especially for less susceptible species, are obtained if the herbicide is applied immediately after cutting with no more than five minutes between cutting and applying herbicide
Adjuvants
Adjuvant: any substance that is added to a pesticide spray mix to aid or modify the action of the pesticide or the physical characteristics of the mixture
Adjuvants
Surfactants: modify the properties of the medium at a surface or interface
Nonionic (uncharged)Anionic (negatively charged)Cationic (positively charged)
Nonionic surfactants are usually recommended for use with
herbicides
Adjuvants
Buffering agents: used to modify the pH of spray mixtures
Water conditioners: used to remove dissolved compounds such as carbonates and bicarbonates from water
Adjuvants
Antifoaming agents: used to overcome excessive foaming
Colorants: materials used to alter the color of a spray mix
Biological ControlClassical biological control: the introduction of reproducing populations of foreign insects or diseases
1967: alligatorweed thrips
1971: alligatorweed stem borer
1970s: two waterhyacinth weevils and a borer
2010: waterhyacinth planthopperHydrilla-specific leaf mining flies
Weevil and a moth for control of waterlettuce
Their development, however, takes years and cannot be expected to solve all invasive plant
problems
Biological ControlFuture implications
Development takes years
Programs are typically implemented by state and federal agencies
The use of herbivores in natural areas should be carefully considered before implementation due to potential issues
with non-target damage
Mechanical Removal
F. Laroche
M. Monroe
Prescribed Burning
Michelle Atkinson, Environmental Horticulture Agent UF/IFAS Manatee County Extension Service
Email: [email protected]
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