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Weed Control in the Landscape - A presentation for Master Gardeners
AUTHOR
Mark Czarnota
,
Eric P. Prostko
The University of Georgia
College of Agricultural and Environmental Sciences
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TABLE OF CONTENTS
Weed Control in the Landscape
Attractive, Functional Landscape
Weeds interfere with the health and beauty of landscaped area
What is a Weed?
Chinese Privet; Kudza
Why Control?
Reason Weeds Survive
Common Weeds
Weed Life Cycles
Seed Germination Factors
Weed Seed Production
Weeds can be a problem 12 months a year!
Summer annual grasses
Crabgrass
Goosegrass
Winter annuals
Annual bluegrass
Common chickweed
Henbit
Hairy bittercress
Summer annual broadleaf weeds
Prostrate spurge
Perennial broadleaf weeds
Dandelion
Wild violet
Pennywort or Dollarweed
Perennial grassy weeds
Wild garlic
Purple and Yellow Nutsedge
Dallisgrass
Control vs. Eradication
Weed Management Strategy
Preventive Methods
Physical Removal and Barriers
Hand Pulling and Hoeing
Mowing
Cultivation
Repeat cultivation to control each flush of weeds
Mulches and Landscape Fabrics
Cultural Methods
Biological Methods
Chemical Methods
Herbicide Classification
Herbicide Classification
Herbicide Classification
Preemergence Herbicide Application Dates
Advantages Postemergence Herbicides
Postemergence Herbicide Precautions
Before You Use Herbicide
Turfgrass Herbicides
Preemergent Turfgrass Herbicides
Postemergent Turfgrass Herbicides
2,4-D Mixtures
MSMA DSMA CMA
Sethoxydim
Atrazine
Turfgrass Fertilizer/Herbicide Combinations
Herbicides for use in Ornamentals
Preemergent Herbicides
Postemergent Herbicides
Equipment
Equipment
Calibration
Calibration
Calibration and Application
Weed management program
Always read and follow the herbicide label!
Turfgrass Web Page
College of Agricultural & Environmental Sciences
SLIDE CONTENTS
Weed Control in the Landscape Developed by Mark Czarnota and Tim Murphy The University of Georgia College of Agricultural and Environmental Sciences
Attractive, Functional Landscape
What is a Weed? Plant out of place Plants causing economic loss Non-native plant (Privet, Ligustrum spp.) Plants whose virtues have not been discovered
Chinese Privet (Ligustrum sinense) Kudza (Pueraria lobata)
Why Control? Plant competition Prevent economic loss Hosts for insects and diseases Maintain landscape beauty
Reason Weeds Survive Hard seed coat, deep burial, germination inhibitors, prolific seed production Persistent vegetative structures: Bulbs, tubers, rhizomes, stolons, and corms.
Common Weeds
Weed Life Cycles Annual: Completes growth cycle in a single growing season (crabgrass). Perennial: A plant that can persist more than two years, and reproduce through roots or seeds (clover). Biennial: A plant that normally requires two growing seasons to complete its life cycle, flowering and fruiting in its second year (wild carrot).
Seed Germination Factors Oxygen Light Scarification (physical removal of the seed coat) Temperature Water
Weed Seed Production Seed / Plant Pigweed >200,000 Lambsquarters >30,000 Crabgrass 53,000 Annual Bluegrass 2,000
Weeds can be a problem 12 months a year!
Summer annual grasses
Southern crabgrass Smooth crabgrass
Goosegrass
Winter annuals
Annual bluegrass Boat shaped leaf tip
Common chickweed
henbit Henbit
Hairy bittercress
Summer annual broadleaf weeds
Prostrate spurge Milky sap
Perennial broadleaf weeds
Dandelion
Wild violet
Pennywort or Dollarweed
Perennial grassy weeds
Wild garlic bulbs and bulblets
Purple and Yellow Nutsedge Leaf tips differ Yellow nutsedge flower Purple nutsedge flower Purple nutsedge rhizome tuber system
Dallisgrass
Control vs. Eradication Control - Process of limiting a weed infestation to a desirable level. Eradication - Elimination of all plants and plant parts.
Weed Management Strategy Identify weed, life cycle, habitat Integrated Pest Management Preventive Physical Cultural Biological Chemical
Preventive Methods Weed-free seed and plant material Screened and sterilized topsoil and soil amendments Keep equipment clean
Physical Removal and Barriers Hoeing and hand removal Mowing Cultivation Mulches and landscape fabrics
Good control method for small weeds Generally easier to control annuals Hand Pulling and Hoeing
Mowing Useful in turf and pastures Mowing reduces seed production of weeds if done before flowering.
Cultivation Disadvantages: Can be expensive, delayed by weather, and may prune crop roots Advantages: Controls most weeds quickly and easily
Repeat cultivation to control each flush of weeds.
Fabrics type affects the degree of weed suppression. Straw, wood chips, pine straw, newsprint, and other organic materials prevent the emergence of weeds and enhance the organic matter content. Mulches and Landscape Fabrics
Cultural Methods Adapted plants Fertility and pH Water management Insect and disease control
Biological Methods Living organisms for weed control Insect (thistle weevil) Grazing animals (Geese) Fish (Grass carp)
Chemical Methods Herbicide - chemical that is used to control, suppress or kill weeds.
Herbicide Classification Preemergence: Applied before weed seed germination (trifluralin). Generally no control of emerged weeds. Postemergence: Applied after weed emergence. Generally no control of unemerged weeds.
Herbicide Classification Contact: Causes localized plant tissue injury. Does not readily move through the plant (glufosinate) Systemic: Readily moves through the plant tissue (glyphosate)
Herbicide Classification Selective: Kills some plant species, but does not damage others (2,4-D) Nonselective: Generally kills all plant species (glyphosate)
Preemergence Herbicide Application Dates Fall - Sept 1 – Oct 1, N.GA - Oct 1 – Nov 1, S.GA Spring - Mar 1 – Apr 1, N.GA - Feb 15 - Mar 15, S.GA
AdvantagesPostemergence Herbicides Flexible application time Spot treatment Small containers Fits well into IPM programs
PostemergenceHerbicide Precautions Avoid windy days (spray drift) Do not apply dicamba mixtures over the root zone of ornamental trees and shrubs Read the label
Before You Use Herbicide Identify weed. Read and UNDERSTAND label . Follow directions carefully. Use only recommended amount! Maintain and calibrate equipment. Do not use on desirable plants not listed on label.
Turfgrass Herbicides
Preemergent Turfgrass Herbicides Annual grass control in all turfgrasses Balan (benefin) Surflan (oryzalin) XL (benefin + oryzalin) Team Pro (benefin + trifluralin) Halts (pendimethalin) Dimension (dithiopyr)
Postemergent Turfgrass Herbicides
2,4-D Mixtures Does not control weedy grasses Good - dandelion, plantains, wild garlic Poor to fair – common chickweed, henbit Use on all turfgrasses except St. Augustine Example = Weed-B-Gon
MSMA DSMA CMA Postemergence control of weedy grasses Use in tall fescue, zoysia, bermuda Initially discolor tolerant turfgrass species Avoid application above 90o F Do not use on centipede and St. Augustine Example = Ortho Crabgrass Killer Formula II
Sethoxydim Controls crabgrass, goosegrass, and sandbur Suppresses bahiagrass Use only on centipedegrass Example = Vantage
Atrazine Can be used on: Centipede, St. Augustine, Zoysia Dormant bermudagrass Cool-season grasses and bahiagrass are not tolerant Comes in both sprayable and granular formulations Depending on the weed, atrazine has both pre and post emergence activity
Turfgrass Fertilizer/Herbicide Combinations Fertilizers can be combined with either pre- or postemergence herbicides. Created so you don’t have to make separate applications of fertilizers and herbicides. Products available from many manufactures selling nearly identical products.
Herbicides for use in Ornamentals
Preemergent Herbicides Surflan (oryzalin) Treflan (trifluralin) Snapshot (trifluralin and isoxaben) XL (benefin and oryzalin) Casoron (dichlobenil)
Postemergent Herbicides Vantage (sethoxydim) Grass-B-Gon (fluazifop-P) Roundup (glyphosate) Finale (glufosinate) Sharpshooter (Potassium salts of fatty acids)
Equipment Hand pump Sprayer Handheld rotary spreader
Equipment Drop spreader Broadcast spreader
Calibration Hand held granular spreaders: Know the size of the area to be treated Weight out granular herbicide needed for that area Uniformly apply the pre-weighted granular herbicide to the designated area
Calibration Push type drop and broadcast spreaders: Many companies sell spreaders to go along with there granular herbicides (i.e. Scott’s, Lesco, etc.). There granular herbicide products will have the appropriate spreader setting listed on the bag.
Pump type sprayers: Calibration and Application Measure the area to be treated. Using the herbicide label, determine the amount of herbicide needed. Measure out herbicide. Mix water and herbicide concentrate. Pressurize sprayer, and uniformly apply herbicide solution to the are. Hand pump sprayer
Weed management program Diagnose problem Evaluate methods Select method Initiate program
Always read and follow the herbicide label!
Turfgrass Web Page www.georgiaturf.com or .org Photographs of major weeds Control recommendations Popular articles, fact sheets Links to pertinent sites