lecture 13 - 3/8/11 Classifica(on of Herbicides BTNY...

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Unformatted text preview: 3/8/11 Classifica(on of Herbicides BTNY 304 DuPont™ Classic® herbicide Dispersible Granules Active Ingredient By Weight Chlorimuron Ethyl Ethyl 2-[[[[(4-chloro-6-methoxypyrimidin2yl)amino]carbonyl]amino]sulfonyl]benzoate…. 25.0% Other Ingredients………………………………………………………………….75.0% Total………………………………………………………………………............100.0% EPA Reg. No. 352 - 436 EPA Est. 220  ­225 Different Chemicals Registered as Herbicides 60 Chemical Families (Classes) 26 Different Mechanisms by Which They Control Weeds 1 3/8/11 Sulfonylureas Classic Telar Option Permit Sedgehammer Autumn Ally Cimmeron Escort chlorimuron chlorsulfuron foramsulfuron halosulfuron halosulfuron iodosulfuron metsulfuron metsulfuron metsulfuron Accent Nic-It Samson Beacon Peak Westar Oust nicosulfuron nicosulfuron nicosulfuron primisulfuron prosulfuron sulfometuron sulfometuron Matrix Resolve Shadeout Harmony GT Harass Express Nuance rimsulfuron rimsulfuron rimsulfuron thifensulfuron thifensulfuron tribenuron tribenuron Premixes Containing one of the above: Accent Gold, Affinity, Basis, Basis Gold, Canopy DF, Canopy EX, Celebrity, Celebrity Plus, Chisum, Cimarron Plus, Cloak, Clarion, Chlormet, Curio, Envive, Equip, Expert, Finesse, Fallout, Halomax, Harmony Extra, Landmark, Lineage, Nimble, NorthStar, Oust, Report Extra, Spirit, Steadfast, Stout, Sulfomet Extra, Synchrony STS, Throttle XP, Valor XL and Yukon. ClassificaHon of Herbicides How herbicides are described or categorized is  ­ a ma9er of convenience  ­ depends on what the describer wants to emphasize in order to best understand herbicides and their proper use. Herbicide Classifica(ons A. Herbicides – by ac(on Selec(ve Non ­selec(ve Contact Translocated Foliar applied (Postemergence) B. Herbicides – by placement (within (me and space) Soil applied (Preemergence) Early preplant Burndown Preplant Early post Preplant incorporated Post Preemergence Directed post C. Herbicides – by ac(vity (ac(ve life) Non ­residual  ­ be9er used as a post applica(on Residual – ac(ve for one season or less Short ­residual – ac(ve from a few days to a few weeks, use in most crops Long ­residual – ac(ve from a few weeks to several months or more Persistent – ac(ve from one to two seasons Highly Persistent*  ­ ac(ve for two or more seasons *long ­residual (highly persistent) herbicides that remain ac(ve longer than two growing seasons, should be used in permanent crops, non ­crop areas, or as an industrial herbicide Environmental concerns and possibly crop injury concerns increase as the residual ac(vity of the herbicide increases. 2 3/8/11 Herbicide Classifica(ons 4. Herbicides – by modes of ac(on (families) 1. Growth Regulators 2. Amino Acid Synthesis Inhibitors 3. Lipid Synthesis Inhibitors 4. Pigment Inhibitors 5. Photosynthesis Inhibitors 6. Cell Membrane Disruptors 7. Cell Growth Inhibitors Mode of Ac(on(MOA) means the mechanism by which the herbicide kills the plant For example, the imidazolinones and sulfonylureas inhibit the synthesis of certain essen(al amino acids. Herbicide Groups According to Where or How They Injure Plants A. Herbicides that injure new growth and have the potential to move from leaves to roots B. Herbicides that injure old growth first and have the potential to move only upward C. Herbicides causing immediate localized injury with little or no movement D. Herbicides applied to the soil and have the potential to injure emerging seedlings ClassificaHon of Herbicides MOA 7 Classes Translocated Growth Regulators Amino Acid Inhibitors Lipid Synthesis Inhibitors Pigment Inhibitors Non ­Translocated Photosynthe(c Inhibitors Cell Membrane Disruptors Cell Growth Inhibitors 3 3/8/11 Herbicide Groups According to Where or How They Injure Plants A. Herbicides that injure new growth and have the potential to move from leaves to roots Translocated herbicides – moves in xylem and phloem, but mostly in the phloem Herbicides are both soil (pre) and foliar (post) applied but mostly foliar applied Injury to both shoots and roots B. Herbicides that injure old growth first and have the potential to move only upward Herbicides move mostly in the xylem Herbicides are both soil (pre) and foliar (post) applied, but mostly soil applied Injury to shoots only C. Herbicides causing immediate localized injury with little or no movement Herbicides do not move Herbicides applied foliar (post) only Injury to shoots only D. Herbicides applied to the soil and have the potential to injure emerging seedlings Herbicides have very limited movement into foliage of seedlings Herbicides applied soil (pre) only Injury to shoots or roots depending on herbicide class Primary Sites of Action of Some Common Herbicides A. Herbicides that injure new growth and have the potential to move from leaves to roots 1. Growth Regulators 2. Amino Acid Inhibitors 3. Lipid Synthesis Inhibitors (Grass Growing-Point Disintegrators) 4. Pigment Inhibitors B. Herbicides that injure old growth first and have the potential to move only upward 5. Photosynthetic Inhibitors C. Herbicides causing immediate localized injury with little or no movement 6. Cell Membrane Disruptors (Contact Herbicides) D. Herbicides applied to the soil and have the potential to injure emerging seedlings 7. Cell-Growth Inhibitors Site of Ac(on (Families) of Herbicides I. Herbicides that injury new growth and have the poten(al to move from the leaves to roots A. Growth Regulators (PGR)  ­ Post 1. Synthe(c Auxin Regulators (SA) – interferes with indole acidic acid (IAA) B. Amino Acid Inhibitors 1. Branch Chain Amino Acid (ALS) Inhibitors – Pre and/or Post Acetolactase Synthase Enzyme Inhibitors Three types of Branch Chain a. Imidazolinones b. Sulfonylureas c. Sulfonanilides 2. Amino Acid Deriva(ves (EPSPS) Inhibitor Post 5 ­ Enolpyruryl – Shikimate – 3 Phosphate Synthase Inhibitor C. Lipid Synthesis Inhibitors (ACCase)  ­ Grass Growing Point Disintegrators  ­ Post Acetyl ­CoA Carboxylase Enzyme Inhibitors D. Pigment (Carotenoid Biosynthesis) Inhibitors (CBI) – Bleachers  ­ Pre and/or Post 1. Diterpene Inhibitors 2. 4 ­HPPD Inhibitors (4 ­HPPD) 4 ­hygroyphrnyl ­ Pyruvate – Dioxygenase Enzyme Inhibitors 4 3/8/11 Site of Ac(on (Families) of Herbicides II. Herbicides that injure old growth first and have the poten(al to move only upward A. Photosynthesis Inhibitors (PSI) 1. Classical PSI – a number of different processes are involved  ­ Pre and/or Post 2. Rapid Ac(ng PSI (Acts Like Contacts with li9le or no movement)  ­ Post III. Herbicides causing immediate localized injury with li9le or no movement A. Cell Membrane Disruptors (Contact)  ­ Post 1. Bipryridilium Herbicides (PS1 Electron Diverters) 2. Protoporphyrinogen oxidase Inhibitors (PPO) 3. Glutamate Synthetase Inhibitor (GSI) IV. Herbicides applied to the soil and have the poten(al to injure emerging seedlings A. Cell Growth Inhibitors  ­ Pre 1. Microtubule Assembly Inhibitors (MAI) – Mostly root inhibitors  ­ Stops mitosis 2. Cell Division Inhibitors (CDI)  ­ Mostly shoot inhibitors – Stops cell division Most postemergence herbicides can also be divided into two basic groups: 1.  Contact herbicides  ­  usually cause rapid death of the plant  ­  do not translocate throughout the plant system  ­  need completely cover the weed to obtain adequate control  ­  Best results obtained when complete coverage is made to annual weeds 2 to 3 inches or less 2. Translocated herbicides  ­ move throughout the plant system before causing death to the plant  ­ kill plants slower than contact herbicides  ­ excessive rates may cause contact destruc(on of plant (ssue causing decrease weed control  ­ do not need completely cover the weed to obtain adequate control  ­ annual weeds can be larger than 2 to 3 inches 5 3/8/11 With perennial weeds, adequate growth before applica(on is required to ensure transloca(on of the herbicide into the underground food and reproduc(ve system. Misjudging the weed spectrum in a field can result in selec(ng and applying the wrong herbicides at the wrong (me, causing less than adequate weed control. ClassificaHon of Herbicides Knowledge About Herbicides To Ensure Maximum Performance 1. How they are properly applied 2. What weeds they control 3. What weed and crop growth stage restric(ons are on the label 4. What rates are needed for weed control 5. What herbicides can be mixed together 6. How environmental limita(ons affect herbicide performance. Herbicide Classifica(on Example Herbicide Herbicide Formula(on Product Rate Range Flexstar 1.88L 1  ­ 1.6 pints/A • Flexstar (fomesafen) is a contact herbicide that controls annual broadleaf weeds in soybeans, including ragweeds, cocklebur, pigweeds, waterhemp, annual morningglories, velvetleaf, Pennsylvania smartweed, and black nightshade. Flexstar will suppress Canada thistle, bindweeds, and climbing milkweed, but does not control lambsquarters. • Mode of ac(on: cell membrane disruptor • Maximum rates of Flexstar: north of I ­70  ­ 1.3 pints; south of I ­70  ­ 1.6 pints. • Apply in a spray volume of 15 to 20 gpa (use 20 gpa in dense foliage) with a spray pressure of 30 to 60 psi. • Apply with COC or MSO (0.5 to 1% v/v) or NIS (0.25 to 0.5%), plus liquid nitrogen fer(lizer (minimum of 1% v/ v) or AMS (minimum of 4 lbs/100 gallons) MSO is the preferred adjuvant. • Flexstar may reduce the ac(vity of postemergence grass herbicides, especially under drought ­stress condi(ons. To avoid a reduc(on in grass control, apply Flexstar 2 to 3 days aher the postemergence grass herbicide is applied, or wait about 7 days aher Flexstar is applied before applying the grass herbicide. See label for more informa(on. • Flexstar ohen causes temporary soybean leaf burn. • Do not apply Flexstar more than once every two years to prevent carryover problems to rota(onal crops. 6 3/8/11 Herbicide Classifica(ons A. Herbicides – by ac(on Selec(ve Non ­selec(ve Contact Translocated Foliar applied (Postemergence) Burndown Early post Post Directed post B. Herbicides – by placement (within (me and space) Soil applied (Preemergence) Early preplant Preplant Preplant incorporated Preemergence C. Herbicides – by ac(vity (ac(ve life) Non ­residual  ­ be9er used as a post applica(on Residual – ac(ve for one season or less Short ­residual – ac(ve from a few days to a few weeks, use in most crops Long ­residual – ac(ve from a few weeks to several months or more Persistent – ac(ve from one to two seasons Highly Persistent*  ­ ac(ve for two or more seasons *long ­residual (highly persistent) herbicides that remain ac(ve longer than two growing seasons, should be used in permanent crops, non ­crop areas, or as an industrial herbicide Environmental concerns and possibly crop injury concerns increase as the residual ac(vity of the herbicide increases. Herbicide Classifica(ons 4. Herbicides – by modes of ac(on (families) 1. Growth Regulators 2. Amino Acid Synthesis Inhibitors 3. Lipid Synthesis Inhibitors 4. Pigment Inhibitors 5. Photosynthesis Inhibitors 6. Cell Membrane Disruptors 7. Cell Growth Inhibitors By knowing a few characteris(cs of each MOA of herbicides, the injury from a par(cular herbicide can be iden(fied through a process of elimina(on. The specific herbicide may not be readily determined, but all herbicides that do not produce the characteris(c injury symptoms can be eliminated. This leaves a much smaller group of herbicides to consider. Many new herbicides today are prepackaged mixtures of two or more herbicides from different mode of ac(on groups. While injury to a given crop could be caused by each herbicide of the mixture, giving a variety of symptoms, it is most ohen noted that one class of herbicidal injury will be prominent. By checking records of the fields in ques(on, or by determining what was applied in adjacent fields, the herbicide which caused the injury can usually be iden(fied. 7 ...
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This note was uploaded on 04/03/2011 for the course BTNY 304 taught by Professor Staff during the Spring '08 term at Purdue University-West Lafayette.

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