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