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Objectives for Using Herbicides

Site PreparationWoody ReleaseHerbaceous ReleaseMid-Rotation ReleaseRight-of-Way Maintenance

How they Control the Vegetation

Kills top and roots --- translocation to reduce sprouting

Kill on contactApplied to soilHormone-type herbicides

Mechanism

AdsorptionTranslocation

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Timing of Application

Stage of Plant DevelopmentCondition of LeavesGrowth StageSoil Moisture

SelectivityWhy some species are affected or Not

Differential WettingBiochemical DifferencesPhenological DifferencesTiming

Chemical Techniques

Foliar SprayBasal SprayStump SpraySoil AppliedGirdling & Injection

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History

2,4,5 – T (2,4,5 – trichlorophenoxyaceticacid)

Registered in about all crops and usesCheapAgent OrangeDioxinBanned about 1980The best thing to happen was to ban it for forestry.

Effectiveness

TechniqueTimingResult

BiologicalEconomic

Crop Safety

Acceptable DamageMechanical Methods Do Damage Trees!

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On-Site Impacts

Non-Target OrganismsSoil HealthEcosystem Recovery

Off-Site Impacts

DriftLeachingRunoffLandscape Impacts

Measuring and Evaluation

When to apply?Was the treatment applied correctly?Was the treatment a success?What were the other impacts?

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Use of Chemicals

“Most problem with pesticides arise from two categories of ignorance about their chemistry and biological effects. Oneform is hysteria on the part of the public, and the other isheedlessness or stupidity of complacent users. Education isthe best solution to both problems. The public is not required to educate itself, but users are.”

Smith, Larson, Kelty, and Ashton. 1997. The Practice of Silviculture Applied Forest Ecology, Ninth Edition.

How to Apply HerbicidesHelicopterGround Equipment

TractorSkidder

BackpackDirected sprayBands or circlesBark application

Basal spray and thinlineOil based

Spot gun

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Helicopter Nozzles

TVB – Thru the Valve BoomMicrofoil Boom (hay rake)Conventional Boom (not for herbicides)Rain Drop (not for herbicides)

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What do we put in the tank?

Carrier (water or oil)Aqueous spraysOil spraysInvert emulsions

HerbicideAdjuvant (increases the effectiveness)

SurfactantsSpreader-StickersCuticle penetration

BuffersAmmonium salts

Herbicides for Silviculture

Aqueous spraysOil spraysInvert emulsions

Making PrescriptionsDefine goals Know your crop and siteIdentify weedsKnow research resultsRead the label and re-read the labelRead and heed the MSDSUse correct volume and applicationUse correct adjuvantsFollow up on efficacy

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Herbicides for Pine Silviculture

ImazapyrChopper - BASF – Ester formulationArsenal AC -BASF – Amine formulationImidazolinone familyInhibits branched amino acid synthesis

ALS (or AHAS)– Acetolactase synthetase

Isoleucine, leucine, valine

Herbicides for Pine Silviculture

GlyphosateRoundup (not registered for forestry) - MonsantoAccord – DowAgroRodeo – Monsanto (aquatic label)Various genericsFamily of its ownInhibits aromatic amino acid synthesis

EPSP– 5-enolpyruvylshikimate-3-phosphate synthase

tryptophan, tyrosine, phenylanaline

Herbicides for Pine SilvicultureTriclopyr - DowAgro

Garlon 4 – DowAgro – EsterGarlon 3A – DowAgro – AminePyridinecarboxylic acid family

PhenoxysBehaves like auxin (IAA)

Over stimulates cell metabolism

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Herbicides for Pine SilvicultureHexazinone - DuPont

Velpar L - LiquidVelpar ULW - GranuleOustar (+ sulfometuron) – Soluble granulesTriazine familyInhibits photosynthesis by blocking electron transport which leads to lipid peroxidation and cellular disintegration

Herbicides for Pine SilvicultureSulfometuron - DuPont

Oust XPSulfonylurea familyInhibits branched amino acid synthesis

ALS (or AHAS)– Acetolactase synthetase

Isoleucine, leucine, valine

Herbicides for Pine SilvicultureMetsulfuron - DuPont

Escort XPSulfonylurea familyInhibits branched amino acid synthesis

ALS (or AHAS)– Acetolactate synthetase

Isoleucine, leucine, valine

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Herbicides for Pine SilvicultureClopyralid

Transline – DowAgroPyridinecarboxylic acid familyBehaves like auxin (IAA)

Over stimulates cell metabolismEffective only on composites and legumes

Herbicides for Pine Silviculture2,4-D

Various brands (read the label)Phenoxyacetic acid familyBehaves like auxin (IAA)

Over stimulates cell metabolism

Herbicides for Pine SilviculturePicloram

Tordon - Dow-AgroVarious formulations

Pyridinecarboxylic acid familyBehaves like auxin (IAA)

Over stimulates cell metabolismLong Residual

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Herbicides for Pine SilvicultureSurfactants

Entry II (ethoxylated tallow amine)– Original Surfactant in Roundup– Excellent safety on pine

• Cannot penetrate the cuticle of pine but can hardwood

– Used for Release

Timbersurf 90NU-FILM-IRSun-it II (methoxylated sunflower oil)

Herbicides for Pine Silviculture

Tank mixesSynergies

Less of bothComplementary controlRule rather than the Exception

Herbicides for Hardwood Silviculture

Same as herbicides for pineCrop herbicides for plantationsInjection and basal sprays for natural stands

Flashback

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Certification

Sustainable Forest InitiativeUse registered pesticidesFollow label

Forest Stewardship CouncilHerbicides are ok but their “dependence”should be reduced.No transgenics

Transgenics

Hysteria Without Substance. (If you don’t like herbicides then you will hate GMO’s!)The Need for Sterility. Resurrection of a Species (American Chestnut)EvaluationEconomicsEthicsHazard Potential

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