HERBICIDES

BIOLOGICAL

• Few with practical application• Xpo (Xanthomonas bacteria) for

Annual bluegrass control

SYNTHETIC

AMINE AND ESTER FORMULATIONS• Adding side group molecules to

active ingredient– Amine: Dimethylamine group to an

acid– Ester: isooctyl group to an acid

SYNTHETIC

Amine formulation• Less volatile and less non-target

effects

SYNTHETIC

Ester formulation• Penetrates leaf

easier • More volatile (vapor

drift)• Winter and early

spring: cooler temps and less leaves

ISOMERS• Different versions of

same chemical– Left hand versus right

hand

SYNTHETIC

ISOMERS• One very effective, the

other not at all• Isolate effective

isomer, get rid of ineffective one– Lower rates, same result

(Acclaim Extra)

SYNTHETIC

SYNTHETIC

SURFACTANTS• Formulation surfactants included

with product• Roundup Pro increased absorption

and rainfastness

FORMULATION

Granular• Less volatile• Won’t stick to leaves• Less phytotoxic effects• Cost more: mostly inert

ingredients, shipping costs• Public acceptance• Less staining and easier clean up

FORMULATION

Liquid• More volatile, better post- effect• Phytotoxic to non-target• Cheap• Bad image

PREEMERGENT

Applied before seed germination– Kills the weed seed as it germinates

• Timing is critical, will not control established weeds

• Aeration does not effect control• A few herbicides have pre and post

activity– Dimension

• Most often a granular that requires water-in

POSTEMERGENCE

• Applied after weeds have emerged

POSTEMERGENCE

HERBICIDE UPTAKESoil-applied• Absorbed by germinating roots

– Some shoots

POSTEMERGENCE

HERBICIDE UPTAKE Foliar-applied• Cuticle, the waxy surface of the

leaf• Leaf hair

POSTEMERGENCE

FACTORS AFFECTING MOVEMENT INTO LEAF

Foliar retention• Water carrier

– Surface tension of water– Reduced leaf contact

POSTEMERGENCE

FACTORS AFFECTING MOVEMENT INTO LEAF

Foliar retention • Spray volume

– Complete coverage for contact– Partial coverage for systemic

POSTEMERGENCE

FACTORS AFFECTING MOVEMENT INTO LEAF

Foliar retention • Rainfall• 6 to 24 hours

POSTEMERGENCE

Systemic herbicides• Move with plant food• Kill all parts of the plant• Rapid growth favorable for kill

POSTEMERGENCE

Contact herbicides• Kill tissue applied, no distribution

throughout plant• Membrane destruction in hours• Control of annuals• Perennials require repeat

application• FAST

MODE OF ACTION

SELECTIVE HERBICIDESSEDGE CONTROL• Manage• Image• Certainty• Monument

MODE OF ACTION

GRASS CONTROL• Vantage controls bahiagrass• MSMA controls crabgrass

MODE OF ACTION

BROADLEAF CONTROLPHENOXY HERBICIDES (after WWII)• 2,4-D, good on dandelion

– Many turfgrasses sensitive

• MCPP (Mecoprop), good on clover

MODE OF ACTION

BROADLEAF CONTROL

PHENOXY HERBICIDES (after WWII)

• Trimec • Bentgrass

Selective

MODE OF ACTION

BROADLEAF CONTROLBENZOIC ACID• Dicamba

MODE OF ACTION

Sulfonylurea family• Manor and Blade on broadleaf

and grassy• Certainty, Sedgehammer and

Monument control of sedge, kyllinga and poa

MODE OF ACTION

Pyridine family• Could replace 2,4-D• Turflon, Spotlight and Lontrel

– 10 times more potent than 2,4-D

• Confront found in compost clippings, limited to commercial use

MODE OF ACTION

Triazolinone family• Quicksilver (Carfentrazone)• Speed Zone

– 2,4-D, MCPP, Dicamba, and Carfentrazone

MODE OF ACTION

Quinolinecarboxylic acid family• Drive for post crabgrass

control

MODE OF ACTION

Triazine family• Atrazine soluble, non-target

damage• Research change frog sex and

lending to death– Centipede – St. Augustine

MODE OF ACTION

NON-SELECTIVE HERBICIDES• Kills most plants

– Glyphosate is systemic (slow)– Diquat is contact (fast)

• QuikPro (Round-up) combines for quick, systemic kill– Limits systemic effect

MODE OF ACTION

Fumigation• Kills plants, MO, seeds, etc.• Methyl Bromide

– Odorless – Teargas added

MODE OF ACTION

Fumigation• Plastic cover to prevent

leakage – 24 to 48 hours

MODE OF ACTION

Fumigation• Methyl Bromide phasout due

to ozone-depleting potential• Dazomet is unclassified

granular fumigant

MOSS

• Low nitrogen and wet areasLow nitrogen and wet areas• Copper containing fungicides, Copper containing fungicides,

soapy solutionssoapy solutions

GENETICALLY MODIFIED TURF (GMO)• Genes isolated from other

plants, animals or microbes for herbicide and insect resistance

• Round-up Ready corn and soybeans

• http://grist.org/industrial-agriculture/a-growing-problem-notes-from-the-superweed-summit/

PLANT GROWTH REGULATOR

• Inhibit growth• Suppress seedheads• Reduce costs and maintenance• Enhance turf quality

– possibly increase roots– improve shade tolerance– improve roll

PLANT GROWTH REGULATOR

CELL-DIVISION INHIBITORS, TYPE 1

• Vegetative growth • Seedhead development

PLANT GROWTH REGULATOR

CELL-DIVISION INHIBITORS, TYPE 1

• Growth inhibition for 3 to 4 weeks

• Yellowing• Embark

PLANT GROWTH REGULATOR

GIBBERELLIN INHIBITORS, TYPE 2

• Suppress cell elongation, internodes shorter

• 3 to 6 weeks• Cutless

ORGANIC HERBICIDES

SOAPS• Fatty acids • Stripping cuticle

– Dehydrate

• Safer and M-pede

ORGANIC HERBICIDES

ESSENTIAL OILS• Clove and cinnamon oil

– Eugenol

• Disrupting cell membranes• Matran and EcoExempt

ORGANIC HERBICIDES

ESSENTIAL OILS• Citrus oil

– Limonene– hand cleaner and degreaser

• Nature’s Avenger

ORGANIC HERBICIDES

VINEGAR• Acetic acid

– Not household vinegar– >20%

• Not listed it as an herbicide• Avoid EPA registration• AllDown and Burnout II

ORGANIC HERBICIDES

PELARGONIC ACID• fatty acid• synthetically produced

– not organic

• Scythe

ORGANIC HERBICIDES

CORN GLUTEN• Applied 4 to 6 weeks before

target dates• Contains 10% nitrogen• First year, expect 50% weed

control• Second or third year 90%