Studied by 11 people
Biological selectivity of weeds
herbicide kills weed with minimal effect to crop because of natural tolerance or through GMOs
What amount of older herbicides were needed
lbs per acre
what amount of herbicide is needed now
ounces per acre
pre-emergence herbicide
before weeds emerge
pre-plant herbicide
before crop is planted
broad cast application
treat entire area
ground applicators
type of broadcast application using tractors
aerial application
broadcast application using crop dusters
herbigation
type of broadcast application using irrigation to distribute herbicide
Banding
application of herbicide on a specific region of the feild
what scenarios is banding used?
used in orchards, vinyards, and nurseries
Directed spray
spray that specifically targets weeds without touching crops
hooded boom
protects crop during directed spray
Spot spray
used primarily for post emergence application for targeting weeds in patches.
can have a 90% savings
advantage to spot spray
Rope wick applicator
touches weeds taller than crop and applies systemic herbicide to weed
Active Ingredient
herbicide doing the work
inactive ingredient
compounds that make the herbicide work better
Additives
designed to help herbicide not react in water and minimize off-target damage
disadvantages to tillage
can’t work in wet soil, and causes land to be more susceptible to dust storms
IWM Integrated weed managment
practices multiple techniques to keep weeds off balance and avoid resistance
elements to IWM
physical, cultural, biological, and chemical
Invasive definition
non-indignous species that becomes established in a natural plant community and replaces native vegetation and is likely to cause economic harm or environmental harm
noxious weed definition
native plant that is injurious to agricultural or horticultural crops and/or humans and livestock
how many noxious weeds in MO?
10 genera 12 species
what percent of species in MO are considered non-native
25%
most abundant invasive weed in US
downy brome. introduced in wheat from europe
are all non-native species a problem?
no, soybeans are fine
reasons plants may become invasive
comes to new area without predators
ability to grow rapidly
we do not recognize them as invasive since they are grown as ornamentals
prolific reproduction so native species out competed
ability to thrive in a wide variety of habitats
exhibit defense mechanisms that put other plants at a disadvantage
abiltiy to exploit limiting factors
invasive species are not recognized by native animals
serecea lespedeza history
brought over as erosion control but it got out of hand
novel weapon hypothesis
invasives produce chemicals that native plants are not used to
enemy release only the healthiest plants
people introduce non-sick plants thus don’t have any of the natural predators
Better competitors hypothesis
must be able to last longer in competition
Smeda theory
start at low levels and by the time people recognize them they are beyond our ability to handle them
where are invasive weeds the biggest problem in the USA
western states and right of ways
FIFRA (Federal insecticide Fungicide rodenticide act)
developed in 1947 from USDA and said that pesticides for shipment must be registered with the secretary of agriculture
What happened before FIFRA
no container guidelines
No restrictions on transport
no warrenty of product
no saftey or effectivess warnings
EPA (Environmental protection agency)
the fire of the OH river catelized the creation of this organization
Goal of pesticide labels
dictate how pesticide is to be used, number of applications, crop to be used on, pre-harvest, rentry intervals and disposal
Who is responsible for pesticide use and how long?
you the user forever
ways to reduce invasive weeds
-eliminate propigation factors
-use effective tools
-establish native species in the open spaces
-education of the public
-understand the weed
-organization of mutliple groups of people
meaning of label for manufacturer
it’s their permit to sell, and how they pay for research and development
meaning of label for buyer or user
how to use the product correctly
meaning of label to federal or state government
method of control, distribution, sale, use, and disposal
label meaning to physicians
source of informationg for treating patients
PIP
Plants incorperates Protectants
Trade name
name of pesticide copyrighted by the company (subject to change)
common name
simplified version of chemical name, can have same common name for different trade names
chemical name
IUPAC name that gives provides the proper chemical nomenclature
General use pesticides
will not cause adverse affects if used as directed
resitricted use pesticides
must possess proper license for each state you use it in
reciprocity
able to transfer restricted use license to ajoining states
Caution signal word
slightly toxic if consumed or inhaled or absorbed
warning signal word
moderately toxic if consumed inhaled or absorbed
danger signal word
very poisonous or irritating to skin or eyes, use with extreme care
who needs a license?
certified commercial applicators
certified non-commercial apllicators
certified public applicators
1A license
agricicultural plant pest control
3 license
ornamental and turf pest control
6 license
right of way pest control
why regulate pesticides
protect the public from adverse effects
ensure proper use of chemicals to reap the full benefits
legistlation ensures consistant use of chemicals
demonstrates to the public that it is safe to use
Food and drug act of 1906
first law specifically addressing pesticides, arsinec in the UK
Insecticide act of 1910
targeted unethecal selling of mislabed pesticides, did not address the toxic affects just made you label them
Federal Food Drug and Cosmetic Act (FFDCA) 1938
set standards for labeling products in response to food poisoning cases
FIFRA act of 1947
addressed the safety of pesticides and the environment. Started looking at residues in the environment and showed that the company was responsible for making safe pesticides
FIFRA ammendment (delaney clause)
stated that no substances known to cause cancer in humans or animals would be deliberately put in food.
problem with delaney clause
did not account for parts per trillion that are now able to be found in food since our technology is so much better.
Food Quality Protection Act (1996)
abolished delaney clause, set a new standard for reasonable amount regarding pesticides, created adult and child standards
Risk assessment cup
introduced with the Food quality protection act, has a risk cup for each pesticide that takes into account the exposure from all different avenues and will not allow the cup to get above a certain level
how are most pesticides discovered
serendipitously
computer assisted modeling (analogs)
Steps for getting a compound released
analog studies
mice studies
primary studies
secondary studies
field trials
EPA requriments for pesticide to be released
pesticide composistion is valid
EPA label good
no adverse affects on non-target organisms and the environment
best canditate for how to handle resistant plants?
non-selective, systemic herbicides and have your crop be resistant
PIP
plant incorperated protectants. plants are build with anti herbivory and weed suppressing chemicals
Early Use Permit (EUP)
can be issued by EPA if it is an emergency and you are going to use it on lesss than ten acres of land or less than one acre of aquatic, effective for 1 year
section 18 of FIFRA
allows the unregistered use of an herbicide for a limited use for a special cost. one year permit, must be an emergency and requires EPA support
Section 24c of FIFRA
special local need. a state can register the early used but it must have a special need. this can be longer than a year but EPA still must approve
4 phases of soil
liquid, solid, gaseous, living. all impact herbicide activity
concentration gradient rule for herbicide
must have high concentration outside plant so it will go to the inside
what happnes to the herbicide if the parent molecule changes
it is no longer the herbicide you started with
Adsorption
herbicide ions stick to the surface of soil particles
clay
the most potential adsorption locations as well as the most surface area since they are so small
size order of soil particles large to small
sand→silt→clay
Kd
soil sorption coefficient
what does kd measure
ratio of herbicide bound to the soil vs free in soil solution
does water solubility affect Kd?
nope, not really
a high Kd value means
more herbicide adsorbed to the soil than free in solution
Absorption
referes to the passage of an herbicide through the surface of a particle
Absorbed herbicides are
unavailable until the particle they are in breaks down
what soils need more herbicide in order to work?
soils high in clay or organic material since more absorption and adsoprtion means less herbicide in soil solution for plant to use
Desorption
the release of absorbed or adsorbed herbicides into soil solution
what is the most important process to initiate desorption?
RAIN it takes away the binding sites on the soil particles from the herbicide and forces the herbicide inot the solution
CEC (cation exchange capasity)
the higher the CEC the greater the ability to store plant nutrients in the soil
Soil CEC increases with
clay and organic matter. generally adsorption of herbicides increases as CEC increases
Acidic pH affect on adsorption
higher adsorption
photodegredation
UVB and UVA create changes in the parent molecules thorugh radiation from the sun
Microbes and herbicide effect
microbes will break down molecules or take pieces off of the parent molecule changing the shape/function
leaching
movement of herbicide with water
Koc
determines how subject an herbicide is to leaching
to find Koc
divide Kd by the wieght fraction of the organic carbon in the soil
high Koc value
correlates to less mobile herbicide (higher kd)
Note
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