Herbicide
* All herbicides are trademarks of their manufacturers
  - have weeds that they are strong on, and weeds they are less strong on
* Avoid use of broad spectrum herbicides.
* Be careful when applying lawn herbicides.
* Many herbicides adhere to organic material and are deactivated.
* Many herbicides are available for use in corn
  - to selectively remove weeds from turfgrasses
  - safe on a crop only when applied at a specific growth stage
  - become more or less tightly bound to soil particles
* Many herbicides have a narrow window of maximum effectiveness
  - growth regulator herbicides as part of their pre mix
  - prohibit application to crops in reproductive stages of growth
* More herbicides are available for soybeans than for sorghum.
* Most herbicides are ineffective if applied while fescue is dormant or after mowing
  - organic compounds and are therefore basically unstable in the environment
* Most herbicides are safe for wildlife
  - if used according to label directions
  - somewhat toxic to newly germinated turfgrass plants
  - become less effective when a plant is under stress
  - can cause eye irritation
  - cause serious injury
  - cross membranes by simple diffusion
  - have the potential for moving into ground water
* Most herbicides lose activity by degrading
  - through chemical and biological degradation
  - show limited effectiveness against melaleuca
  - work best if sprayed during hot weather
* Some herbicides are animal carcinogens
  - at less risk for resistance because they have multiple sites of action
  - available both as liquids and granules
* Some herbicides are available in both amine and ester formulations
  - combination with a fertilizer
  - under more than one trade name
  - mixed with toxic herbicides and diesel fuel
  - more effective if applied with irrigation water
  - selective and can be applied over trees to kill the targeted weed species
  - selective, killing only broadleafed plants or grass plants
  - toxic to fish or other wildlife
* Some herbicides are very damaging to young seedlings
  - persistent and mobile and can contaminate ground and surface water
  - residual, affecting plant growth for years
  - can be useful to spot treat smaller areas of infestation
* Some herbicides can cause corn to leaf out underground
  - similar injury to developing corn
  - control pest broomrapes but they develop herbicide resistance
  - damage desirable species as well
  - do have water use restrictions
  - even make kudzu grow better
  - exhibit both soil and foliage activity
* Some herbicides have a narrow margin of safety between injury and effective weed control
  - residual life in the soil of one, two, or more years
  - both preemergent and postemergent activity
  - swimming, drinking, fishing, irrigation, and water use restrictions
  - increase the activity of others
  - kill every plant they contact, while others kill only certain plants
* Some herbicides kill weeds by breaking down membrane structure
  - disrupting the manufacture of chlorophyll
* Some herbicides leave a residue in the soil that can damage subsequent crops
  - behind grass monocultures and little food for wildlife
  - literally burn up their target plants by over accelerating growth or metabolism
  - make kudzu grow better and many have little or no effect
  - persist in the soil and control all stages of plant growth
  - reduce the activity of others
  - require incorporation to obtain consistent weed control
* act by interfering with specific processes in plants.
* affect processes that occur when the plant grows.
* also control vegetation well
  - have a major affect on the wildlife
* appear to be a major pollutant at all times and locations
  - work better when combined with competitive crops
* applied by aircraft in forestry unavoidably appear in small quantities in forest waters.
* are a crucial tool in our efforts to control weeds
  - generic organic form of pesticides
* are also available to reduce the population
  - economical and effective
* are an effective tool where high quality turf is desired
  - essential component of crop production in Australia
  - available depending on the crop grown
* are available for control of dandelion seedlings in cereal crops
  - weed control in lettuce
* are available in broadleaf crops for suppressing quackgrass
  - cereal crops, canola and peas
  - most crops for control of redroot pigweed
  - several formulations
* are available to control grasses in glads
  - most weeds before and after planting
  - available, but there are no biological control agents
  - chemicals designed to kill weeds
* are chemicals that inhibit or interrupt normal plant growth and development
  - retard or kill plant growth
  - used for killing weeds or inhibiting plant growth
* are chemicals used to control weed growth
  - kill weeds in agriculture as well as household gardens
  - effective in eradicating the poison ivy plant
  - either foliar active, soil active, or both
  - especially dangerous when improperly handled, applied or disposed of
  - essential to sustain yields
  - exempt only when used as weed killers for the commercial production of plants
  - for emergencies
  - generally quite immobile in soil
  - growth regulators and different herbicides have different modes of action
  - made to target specific metabolic pathways in the target plant
  - major contributors to control of weeds in annual crops
  - more effective at lower weed densities
* are most effective if applied before weeds start to bolt in the spring
  - when integrated into a total package of control measures
  - much less effective once they have begun to head out
  - now available to control grasses in iris beds
* are often an important part of a weed control program
  - the most flexible and affordable option for thistle control in pastures
* are only necessary when clear cutting for coniferous reforestation is practiced
  - substitutes for hand labor and are only as effective when properly applied
  - place on grass in subdivisions to kill weeds
  - poison substances used to inhibit weed growth in gardens, lawns, and fields
  - safe and effective if product label instructions are followed
* are the favored method of weed control for most farmers
  - leading type of pesticides, in terms of both user expenditure and volumes used
  - most widely used treatment for leafy spurge control
  - primary pesticide inputs
  - therefore the preferred method of weed control
  - useful, effective tools in the control of weeds in turf areas
* boost soil water storage.
* breakdown more slowly than normal under dry soil conditions.
* can accumulate in insects through bioaccumulation
  - also control some common pasture weeds
* can be expensive and potentially dangerous
  - safe and effective when applied properly
  - toxic to aquatic plants and animals
* can be useful in controlling large sweet clover populations in degraded areas
  - managing persistent weeds
  - create significant economic damage to croplands in agricultural areas
  - damage valuable plants such as ornamentals, so use care
  - effectively eradicate giant reed
  - harm or destroy wildlife habitats
* can have both beneficial and harmful residual effects on the next crop
  - replanting restrictions
  - kill individual tufts, which are easily hidden by vegetation
  - occur in nature or they can be created synthetically
* can provide a simple killing method, but many farmers use other methods, such as tillage
  - cost-effective weed control with a minimum of labor
  - save a lot of labor
* cause burning or abnormal growth
  - infertility
  - prostate cancer
* containing MCPA and clopyralid provide effective control when applied as a foliar spray
  - triclopyr can also be useful
* control weeds effectively when applied in proper amounts at the right time.
* degrade in the soil by either chemical or biological processes
  - for a number of reasons
* destroy nitrate accumulating weeds, making pastures and forage crops safer.
* differ in the amount of time they require before becoming rainfast
  - translocation within a plant
* do so with devastating success.
* fall into three major categories.
* generally work best on young, succulent annual weeds, such as crabgrass.
* have different modes of action and can be selective in the type of plants they affect
  - several different modes of action
* is pesticide.
* kill mainly broadleaf weeds and grass
* kills weeds.
* play an important role in morning glory management.
* provide a convenient, economical, and effective way to help manage weeds
  - growers and land managers with a way to chemically manage weeds
* reduce some species of plants important as food for pheasants
  - the amount and diversity of food plants available, both browse and forbs
* refer to compounds that are used to destroy weeds and other undesirable plants.
* selectively control unwanted vegetation within the crop.
* tend to be more effective on smaller plants
  - work well
* treat the symptoms of the problem without correcting the cause
  - weed problems
* used in rotations with other crops are the best means for control in sunflower fields.
* used on coastal land can kill or damage eelgrass
  - lawn weeds also kill aquatic plants
  - lawns take a terrible toll on wildlife
* vary in their ability to translocate within a plant.
* work best during the fall
  - when the weed is actively growing
  - but are labor intensive
  - several ways to kill unwanted weeds
* works best on poison oak that has already formed berries.