Adv Silv exam 2 pt. 2 Herbicides

What type of herbicide is most likely to cause health issues for humans?

Contact herbicides. (weed smokers example)

phloem

transport sugars downward

cambium

A layer of cells in a plant that produces new phloem and xylem cells.

xylem

water and nutrients upward

"good root absorption" herbicides are transported through what?

xylem

"good foliar absorption" herbicides are transported through what?

phloem

True or false: there are herbicides that travel through the phloem and the xylem?

true

What kind of herbicide do we mainly use in forestry?

translocated

Mix with each other and it makes a solution

Polar

Polar molecules like...

polar molecules

Examples of non polar

waxes, oils, fats

AI

active ingredient

WP

Wettable powder

Differential wetting

herbicide solution spreads or sticks differently on plant surfaces, causing some plants or plant parts to absorb more herbicide than others.

What factors influence differential wetting?

leaf shape, angle, arrangement, hairiness

do very hairy leaves like beauty berry absorb well or poor?

poor

Morphology

structure

Vast majority of functional rings in a ring porus tree is in the outer_______ rings

2-3

true or false: diffuse porus trees have a lot less functional rings than ring porus.

false

Meristem tissue

plant tissue made of rapidly dividing cells that produce new growth

Where is the meristem tissue located on woody plants?

tips of shoots

Where is meristem tissue located in grasses

base of stem in the soil

Detoxifying herbicide

When all components are together it is harmful, but when you break apart the molecular structure, it is harmless. Just like when you take lactase to break down lactose.

Rank the SYP in order of most resistant to least resistant to herbicide

loblolly, slash, longleaf, hardwoods

Auxin

woody plant enzymes

Once herbicide enters a tree via hack and squirt, where does it go?

side to side via ray cells

hydroscopic

water absorbing

RTU

ready to use (tank mix)

When a company makes a herbicide, they get _______ ________ rights for x number of years

exclusive patent

delayed stump treatment over 2 hours after cutting results in...

decrease of absorption

Why should you treat stump immedietly after cutting?

air bubble form in vessels and it acts as a cork

If you kill a tree that has its leaves can cause aesthetics issues called:

brownout

Soil herbicides need ___________ for activation.

1" of rainfall

What is the average time it takes for a herbicide to break down? What breaks it down?

2-3 months, bacteria, UV light, high temperatures

ULW

Ultra Light Weight

What is banding application?

Spraying plantation pines with a resistant herbicide over top of the rows. This saves money by not broadcast spraying.

3 uses of herbicides

Timber management, Wildlife management, Utility lines

Contact herbicide

destroys tissue on contact

Translocated herbicide (3 steps)

must be absorbed by plant, must move through plant, toxic reaction

Cutin

Leaf surface covered with wax

Herbicides with polar molecules are often...

Water soluble

Herbicides with nonpolar molecules are often...

oil soluble

What is the purpose of a surfactant?

gets the water to not bead up and allows it to get through cracks

oil dissolves cutin to to allow herbicide to enter the leaf, but how does a nonpolar molecule move through a polar environment?

may be a chemical reaction changing to polar compound to aid translocation.

True or false: there are degrees of polarity. Ex. Slightly polar, strongly polar

true

Preemergence herbicides

controls undesirable before or just after emergence. (2" tall)

Postemergence herbicide

controls undesirable after emergence

Give an example of a herbicide that is both pre and postemergent.

Arsenal

Herbicide selectivity

We want to kill only unwanted plants, not others

Morphological selectivity

due to differences in plant structure

Biochemical selectivity

variations in nature and activity of enzymatic systems between species

Phenological selectivity

due to age and activity of vegetation

Selective placement

placing herbicide on/around only those plants to be killed

What results do you get with low concentration?

poor weed control

What results do you get with proper concentration?

good weed control

What results do you get with high concentration?

crop damage

MOA

modes of action

MOA for Preemergence (4)

Prevents germination, stunts root formation, disrupts photosynthesis, burns shoot growing through soil

MOA for postemergence

disrupts photosynthesis, deranges plants physiology, deranges cell metabolism

Auxin type herbicides

Mimics auxin hormone

"birth of selectivity"

2,4 D. developed during WW2

Why do you only girdle trees 12" and above?

smaller trees you can cut down with the same effort

Narrower girdles have higher tendencies to...

callus over. especially in the spring and diffuse porus species.

Frill gidle

keep chips on the cut to allow for herbicide to get caught in them

What is a disadvantage of the hypohatchet?

it gets clogged easily

Basal Bark treatment

spraying lower 12 - 15 inches of trunk with herbicides

Give 3 examples of trade names with hexazinone as the active ingredient

Velpar ULW, Velpar L, and Pronone 10G

Where do you not want to apply Hexazinone?

wetlands, poorly drained upland areas with high organic matter, sandy soils with high water table.

Why is Hexazinone often used less on clayey soils?

Because of higher rates and cost because it binds to clay particles and organic matter, reducing how much is available for plant uptake.

How does Hexazinone do its damage?

soil-active herbicide that is absorbed by plant roots.

Preferred timing for hexazinone treatment?

early spring to early summer, rainfall must activate, Harvested or burned areas must have resprouted

Susceptible species to Hexazinone

red and white oaks, sweetgum

resistant species to Hexazinone

Pines, redcedar, yellow-poplar

What is the most widely used AI in forestry?

Imazapyr

Where do you not want to apply imazapyr ?

palmetto flats, and where resistant species are abundant

timing of application for imazapyr

from full leaf to color change with best results reported in late summer and early fall.

Susceptible species to Imazapyr

sweetgum, water oak, privet

resistant species to imazapyr

pines, redcedar, redbud

What kind of herbicide is imazapyr?

Systemic, moves through the plant after being absorbed by leaves and roots

Antagonism

when one herbicide reduces the effectiveness of another when they are applied together.

True or false: Glyphosate is active in soil.

False, must be sprayed on leaves and wood

Susceptible species to glyphosate

sweetgum, water oak, white oak

resistant species to glyphosate

hickory, black cherry, privet

timing of glyphosate

full growing season until extensive leaf fall

Escort is good at killing...

dewberry/blackberry

Susceptible species to Picloram

red oak, white oak, pines

resistance species to picloram

sassafrass, sumac, grasses

timing for picloram

after full leaf to late summer

how long should you delay planting pines after treating site with picloram?

6 months

When should you not apply picloram?

high chance of surface or groundwater contamination, or with crops nearby

2 examples of trade names with imazapyr as the AI

Arsenal, chopper

2 examples of trade names with glyphosate as the AI

accord, roundup

2 examples of trade names with Picloram as the AI

tordon K, tordon 101