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45 Cards in this Set

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  • Back
What is the difference between acute effects and delayed effects?
Acute is within 24 hrs; delayed is withing 36 hrs
Define residue, solvent and exposure.
Residue-- any part of herbicide that remains in environment
Solvent-- any liquid that you will dissolve stuff into
Exposure-- contact or inhaling chemical
Define these formulation terms: agitation, insoluble, soluble, volatile,target/nontarget pests.
agitation-- stirring
insoluble-- doesn't dissolve in liquid
soluble-- does dissolve
volatile-- evaporate rapidly
target pests-- pest where control method is geared
nontarget pests-- affected by control method but not target
What does caution, warning and danger refer to?
hazard statements
If you needed to get a label for a state of emergency, what label would you get?
Section 24c
If you needed to get a public health label, what label would you get?
Section 18
What label is for experimental use?
Section 5
What is a fully registered label?
Section 3
What are the (dis)advantages of emulsifiable concentrates (EC)?
Adv: easy
Disdv: highly conc so easy to overdose, easily absorbed by skin, corrosive
What are the (dis)advantages of liquids (L), flowables (F), and water dispersed liquids (WDL)?
Adv: suspension, seldom clog nozzles
Disadv: needs moderate agitation, forms residue
What are the (dis)advantages of wettable powders (WP)?
dry, fine dust--mix with water, usually >50% AI
Adv: easy to store, cheap, no agitation
Disav: doesn't dissolve in water, dust inhalation, will clog screens
What are the (dis)advantages of dry flowables (DF) and water dispersible granules (WDG)?
Granular size, must be mixed with water
Adv: easy to measure, less inhalation problem
Disadv: constant agitation, hard to mix
What are the (dis)advantages of micro encapsulated (ME)?
Dry or liz encaps. in polymer
Adv: slow-release, easy to mix
Disadv: constant agitation, bees will take
What are the (dis)advantages of soluble powder (SP) and granular formulations (G)?
Put out through spreaders, low AI 1-15%
Adv: ready to use, little drift or hazard, can treat soil
Disadv: can't treat foliage, needs rain
What is the purpose of an additive study?
evaluate weed densities on a fixed crop species
What can you use an additive graph for?
predict thresholds
crop response at varying weed densities
What can a replacement study determine?
Which species is more competitive
Understanding of weed-crop dynamics- interspecific vs intraspecific competition
Which competition graph starts with a monoculture of one species and gradually replaces that species with a second species until that species reaches a monoculture?
Replacement study
What does the Area of Influence determine?
the effect that a given weed distance has on crop growth/yield
What are the advantages and disadvantages of an additive study?
Adv: directly applicable to field production practices, conducted under producer conditions, known weed densities, good for determination of duration of weed-free and weed competition periods, can obtain growth and development data
Disadv: specific competitive relationships are difficult to determine
What are the (dis)advantages of replacement studies?
Adv: ideal for competition models, suited for greenhouse studies, determine weed/crop competitiveness, can determine specific parameters
Disadv: not directly applicable to field, difficult to conduct in field
What are (dis)advantages of the Area of Influence?
Adv: accurate measurement of single weed effects, develop weed models, can obtain growth and development data
Disadv: weed to weed variability, difficult to establish and maintain
What is the difference in adsorption and absorption?
Adsorption is when a herbicide attaches to surface of solid
Absorption is the uptake of a chemical
How can soil composition affect herbicide phytotoxicity and persistence?
through adsorption, leaching and volatilization
What is the difference between residual, persistent and highly persistent herbicide?
Residual has a halflife of 5-30 days
Persistent has halflife of 30-90 days
Highly persistent has halflife of over 90 days
How do you reduce volatilization?
Can incorporate it
Change formulation to granular
Change molecular formula
What is a rainfree period?
time after application of a herbicide that has to pass before rain falls or irrigation
How can herbicides by lost?
adsorption, degradation, leaching, runoff, chemical decomposition, photo decomposition, volatization
What factors determine the length of time herbicides persist?
soil factors, climatic conditions, herbicidal properties
What are characteristics of growth regulators?
Affects cell division, cell enlargement, protein synthesis and respiration
Act by upsetting normal hormone balance in plants
Systemic- phloem to meristem
Limited activity on grasses
What are symptoms of growth regulators?
Broadleaf-- cupping, crinkling, strapping, drawstring effect
Grasses-- rolling, crinkling, blasted grain heads
Epinasty-- uncontrolled growth
Death-- days to weeks
What are characteristics of photosynthetic inhibitors?
Inhibit photosynthesis at PSII--> build up of radicals
Most are PRE
Rapid burning of tissues
What are symptoms of photosynthetic inhibitors?
Interveining or veinal chlorosis
What are characteristics of amino acid synthesis inhibitors?
Most have soil and foliar activity
Soil residual activity
Low use-rate herbicide
Can be Branched Chain Inhibitors(Acetolacetate Synthesis inhibitors) or Arommatic AA Inhibitors
What are symptoms of Branched Chain inhibitors (ALS)?
Shoot meristem will yellow then die
Yellow streaks on leaves
Pink or purple veins
stunted root growth
What are the symptoms of Aromatic AA inhibitors (EPSP)?
Initial chlorosis
Followed by necrosis
Possible deformed leaves
Sometimes see multiple shoots as regrowth
Slow death
7-14 days for symptoms to appear
What are characteristics of Cell Membrane Disruptors?
Cell membrane disruptors
- destroy cell membranes
- desiccation of plant tissue
Organic Arsenicals
- Similar activity but eact MOA and site of activity unknown
What are symptoms of cell membrane disruptors?
- rapid yellowing and plant tissue desiccation
- usually appear on leaf tips 1st
- speckled leaf burn on off-target drift
What are characteristics of seedling growth inhibitors?
Root inhibitors
- interrupt cell division in seedling
- stops root growth
Shoot inhibitors
- disrupt protein synthesis, cell div, and cell enlargement
- weakens cell membrane
What are symptoms of seedling growth inhibitors?
- stubby roots
- plant stunting
- P deficiency
- Broadleaf: swollen hypocotyls
- improper leaf unfurling, crinkling
- puckering
What are characteristics of lipid synthesis inhibitors (ACCase)?
- disrupt lipid synthesis
- stops plant growth and eventual death
- only grass plants
- plant cells and cell organelles
- Systemic
What are symptoms of lipid synthesis inhibitors?
- discoloration and disintegration of meristem regions
- chlorosis --> necrosis
- leaf sheaths: brown and mushy
- affected areas become rotted
- symptoms over entrie plant
What are characteristics of pigment inhibitors?
- destroy green pigments by inhibiting carotenoids
- absorbed by roots
- translocated to shoots by xylem
What are symptoms of pigment inhibitors?
- Cause white foliage (albino growth)
- symptoms on cotyledons and true leaves
What are characteristics of PPO inhibitors?
- inhibits the precursor to chlorophyll (protoporphyrinogen)
- all membrane oxygen radicals produced
- very selective PRE but nonselective POST