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65 Cards in this Set
- Front
- Back
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4 fates of a herbicide?
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1. Nothing, Volitalize
2. Enter Apoplast and move up 3. Enter Symplast and move up and down 4. Enter both apo and symplast |
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How do contact herbicides work?
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No movement in plant, They destroy cell membranes of the cells that they hit first.
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Are contact herbicides fast or slow?
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Fast, within hours
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Why are contact herbicides less effective on perennial weeds or grasses and are most effective on broadleaf weeds?
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They usually have larger growing points and they arebelow ground so the contact herbicide will kill the top and the bottom will grow back...
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Contact herbicides do not . . .
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Translocate
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What is the Apoplast?
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Interconnecting walls and water filled xylem. "the dead" part
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Living cells connected to the plasmodesmata are reffered to as. . .
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the Symplast
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What is the primary route for translocation of water nutrients and herbicides from root to shoots?
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Apoplast
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What drive apoplast movement
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Transpiration- the difference in water potentials
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how does drought affect apoplastic movement?
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Its slows it because the plants stomata closes and it doesn't transpire.
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Where does apoplastically moved herbicides accumulate? Young or old?
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In both, but more of the older leafs because they transpire the most.
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Where do symptoms show on apoplastically transported herbicides?
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On the leaf tips, similar to contact herbicides.
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What must all herbicides pass through to enter the plant?
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Plasmamembrane
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Herbicide absorption is complete when the herbicide is released at the sink for this movement?
The source for this movement? |
Apoplastic
Symplastic |
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In passive transport, is a lipophilic or hydrophilic herbicide quicker?
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Lipophilic
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What is the symplast transport made to transport
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Photosynthetic product (sugars)
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What are the source and what are the sink in Symplast
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Mature leaves
Roots |
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What leads to good herbicide translocation in the symplast
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High light
Adequate soil moisture warm temperature |
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Where is the source of photosynthate
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The Mature leaves
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When should symplast herbicides be applied?
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During the growing period, dormant period is worthless
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what lifecycle is extremely effected by symplast herbicides?
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Perennials
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Why would you want a symplastic herbicide to kill slowly?
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because you need the foliage and photosynthate to transport the herbicide throughout the plant.
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Why do symplastic herbicides accumulate?
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young tissue
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How does the time of year effect symplastic herbicide movement?
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in spring carbon flows up the stem, in fall it flows down to roots, in winter it flows below ground...
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One possible outcome of herbicide fate is become metabolized.... explain?
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The herbicide gets an oxygen molecule binded to it and it is then considered oxidized and will metabolize.
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define pro-herbicides?
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A herbicide that requires one or more metabolic steps to metabolize
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3 components that must happen for a herbicide to be effective?
What is a fourth factor that will determine if the cells die? |
Contact, absorption, and translocation
Entry into the cell and avoidance of metabolism |
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a few (3) places where the herbicide can effect a cell...
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Vacuole
Nucleus chloroplast |
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What happens with amino acid inhibitors?
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The act in the chloroplast, Cause a lack of amino acids which prevents protein synthesis, growth will cease.
Not clear where the plant dies. |
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Examples of amino acid inhibitors?
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ALS Inhibitors, EPSP synthesis inhibitors.
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What do auxin mimics do and whats the outcome...
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provides the plant with a huge amount of auxins, Acts on the plasma membrane, rapid distorted cell growth...
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Why aren't grasses usually effected by IAA (Auxin mimics) 3
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The arrangement of vascular tissue
Metabolizes 2,4-D Roots will excrete the herbicide. |
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What do lipid biosynthesis inhibitors do?
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Prevent fatty acid synthesis...
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Why are broadleaf plants uneffected by Lipid biosynthesis inhibitors? ACCase inhibitors?
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Broadleaf plants have a different ACCase and it leaves no binding site for the herbicide.
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Where do ACCase inhibitor effect the plant? (Lipid biosynthesis inhibitor)
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happens in the cytoplasm
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Where do Microtubule assembly disrupters take place?
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In the nucleus and cytoplasm
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What happens with microtubule assembly disrupters?
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They bind to tubulin during metaphase and prevent cell divsion. This causes cells to lose support of the plasma membrane.
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Where do photosystem inhibitors take place?
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In the chloroplast
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What happens in a photosystem inhibitor...
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cause the chlorophyll to create too many free radicals which causes leaky membranes.
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What happens in pigment inhibitors and where does it take place?
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Prevents cartenoid production
Fails to protect chlorophyll Takes place in Chloroplast |
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2 goals to registration of a herbicide.
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to ensure that its use will not harm humans or the environment
To make sure that the benefits will outweigh the risk |
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3 acts involved with registration
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FIFRA
FFDCA FQPA |
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FIFRA =
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Federal Insecticide, Fungicide, and Rodent Act
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FFDCA =
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Federal Food, Drug and Cosmetic Act
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FQPA =
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Food Quality Protection Act
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What are the basic provisions to FIFRA (3)
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EPA must register pesticides
Must Follow the label A company must be registered to sell |
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FFDCA basic provisions (1)
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sets tolerance on pesticides
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FQPA basic provisions (2)
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Amended both FIFRA and FFDCA
Set a new safety standard tolerance requires pesticide reregistration |
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4 agencies involved in law and enforcement of pesticides
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EPA
ODA FDA USDA |
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3 types of registrations and explain
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SEction 3- Federal registration
Section 24 (c)-Special local needs Section 18- Emergency Exemption |
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How long does the Emergency exemption last in section 18 registrations
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1 year
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Allows unregistered use of a pesticide for 15 days?
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Crisis Exemption
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Who created the Workers Protection Standards and what does it do?
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EPA, It makes sure that workers are protected and educated to reduce risk
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2 kinds of Employees in pesticides
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Pesticide "handlers"-Those who actually mix load and apply pesticides
Agricultural "workers"-The people who deal with the plants, any kind of ag worker. |
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Ways to limit liability when using pesticides name 3
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Read and follow the label instructions!
Have insurance Have suitable licensing for the pesticide Inform neighbors Be aware of and record weather conditions Post application notices (REI) Maintain records (PURS) |
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Describe classical biological control?
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When you get a pest from somewhere... go to the pests home to find the bio control
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For release of a bio control agent what is required
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TAG approval is required through many studies
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Difference between bio and chemical control
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Bio controls can't be recalled
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Herbicides that are ACCase's Acetyl CoA Carboxylase (4) (ACCase) inhibitor
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Clethodim
Diclofop Flufenacet EPTC |
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Herbicides that are Auxin Mimics(4)
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Aminopyralid
Picloram 2,4-D Triclopyr |
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ALS inhibitors- amino acid inhibitors(3)
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Mesosulfuron
Imazamox Halosulfuron |
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Photosystem II inhibitors(2)
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Diuron
Metribuzin |
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Microtubule Assembly inhibitor(1)
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Trifluralin
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Photosystem I inhibitors (1)
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Paraquat
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EPSP synthase inhibitor (1)
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Glyphosate
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