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Technical Aspects of Paddy Weedicides

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Training module for the new comers who enter in to Sri Lankan Agrochemicals industry

Publié dans : Sciences

Technical Aspects of Paddy Weedicides

  1. 1. Presents by: Krishan F. Motha B.Sc.(Agric) Hons (Sp) TECHNICAL ASPECTS & ADDRESSING FIELD ISSUES OF KISEKI
  2. 2.  Basic Technical Aspects of Pesticides  Development of Herbicide Resistance & Resistance Management  Technical Aspects of Kiseki  How to Address Field Issues of Kiseki
  3. 3. • How would you claim a product is superior in quality than the other products? Ex:- Round Up over other Glyphosate brands? Ex:- Nominee over other Bispyribac sodium brands?
  4. 4. • What decides the qualityof a product? Answer: An unique formulation of the product decides the superior quality
  5. 5. • Then what is a formulation ? A mixture of chemicals which effectively controls a pest Eg: Nominee product is a formulation, and bispyribac sodium is its Active Ingredient
  6. 6. • Formulation •AI + Inert ingredients Decides the Efficacy, Toxicity & Stability of the product
  7. 7. Active ingredient/s - listed in the product label Inert ingredients -are the company secrets But Decides storage, handling, safety, application, or effectiveness
  8. 8. • What do manufacturers consider when creating a formulation? • The type of surface • Habits & Nature of the pest • Stability, Toxicity, Safety • Price • Spray equipment • Runoff & Drift
  9. 9. AI (Liquid or Solid) Inert Ingrediants Surfactants-Dispersants,Wetting agents Solvents Emulsifiers Defoamer Stabilizer Anti-microbials Anti-freeze Pigments/Colorants Buffers etc. Formulation Commercial Product Formulation
  10. 10. FORMULATION TYPES Liquid Sprayable SL –Soluble Concentrate SC –Suspension Concentrate EC –Emulsifiable Concentrate SE- Suspo Emulsion ME -Microemulsion OD –Oil Dispersion CS –Microencapsulated Particles Dry -Sprayable WP –Wettable powders WG or WDG –Water dispersible granule Dry –Spreadable Granule GR –Soil applied Granule on inert or fertilizer carrier
  11. 11. SUSPENSION CONCENTRATE (SC) • A stable suspension of solid pesticide(s) in a fluid usually intended for dilution with water before use • Suspension is stable & not settling out AI= 0.1- 60%
  12. 12. EMULSIFIABLE CONCENTRATE (EC) • A solution of a pesticide with emulsifying agents in a water insoluble organic solvent which will form an emulsion when added to water • Complete Hydrophilic-lipophilic balance is reached for stable formulation AI= 0.1- 40% Eg: Matari Metamifop 10% EC
  13. 13. SUSPO EMULSION(SE) • A solution of a pesticide with two AI components which one is in a emulsifying agent in a water insoluble organic solvent which will form an emulsion when added to water and the other AI is suspended in the same water • Practiced when mixing two AIs when one is water soluble and one is soluble in organic solvents. Eg:- Kiseki Bispyribac-sodium 4% + Metamifop 10%
  14. 14. • What is herbicide Mode of Action? How a herbicide affects a plant at the tissue or cellular level Herbicides with the same mode-of- action will have the same absorbance type, translocation (movement) pattern and produce similar injury symptoms
  15. 15. PADDY SELECTIVE MOA IN SRI LANKA Mode of Action Importance Examples Amino acid synthesis (ALS) inhibitors Total killers Sulfonyl ureas- Sedge killers Bispyribac sodium, Sulfonyl ureas, Pyribensosim, Phenoxylam Lipid synthesis (ACC ace) inhibitors All are grass killers High doses cause phytotoxicity Fenoxyfop-p-ethyl, cyhalofop- butyl, Metamifop Cell division inhibitors Form a thin layer on soil Pretilachlor, Pendimethilene Inhibition of emerging shoots Stop cell elongation Thiobencarb Photosynthesis inhibitors Propanil Pigment inhibitors Cause to bleaching effect Clomazone Synthethic auxins Hormonal effect MCPA, Quinclorac
  16. 16. • What are the pesticide Interactions when mixing different MOA molecules together? 1. Additive effect 2. Synergistic responses 3. Antagonism 4. Enhancement 5. Incompatibility
  17. 17. PESTICIDE INTERACTIONS 01.Additive effect • Mixture’s response is as the combined effects of each material applied alone • The products neither hurt nor enhance each other • These mixtures save time, labor & equipment use 02.Synergistic responses • When two pesticides provide a greater response than the added effects of each material applied separately 03. Antagonism • When two pesticides applied together produce less control than if applied each material separately • In addition antagonistic responses also may increase damage, or phytotoxicity, to plants antagonism is one kind of incompatibility • Eg: Fenoxyfop-p-ethy + MCPA mixture cause antagonism
  18. 18. 04. Enhancement • Occurs when a pesticide is mixed with an additive to provide a greater response than if you applied the pesticide alone • Eg:- Mixing a surfactant with a pesticide 05. Incompatibility • Two or more pesticides, or a pesticide and a fertilizer, are compatible if no adverse effects occur as a result of mixing them together • Conversely, deactivation of an active ingredient often occurs with chemical incompatibility • Most affected by temperature, tank pH and length of time that you hold a spray mixture in the tank • Physical incompatibilities occurs by inert ingredients of a formulation • Mixture may become unstable, forming crystals, flakes, gel, oil, grease or sludge that may clog spray equipment. PESTICIDE INTERACTIONS
  19. 19. • What is Herbicide Resistance? Inherited ability of a weed to survive against a herbicide application to which the original population was susceptible
  20. 20. HERBICIDE RESISTANCE
  21. 21. HERBICIDE RESISTANCE •How does it occur?
  22. 22. Season 1
  23. 23. Season 2……7, 8
  24. 24.  284 Resistant weeds  171 Species (101 dicots & 69 monocots)  Over 270,000 places/fields HERBICIDE RESISTANCE AROUND THE WORLD
  25. 25. HERBICIDE RESISTANCE AROUND THE WORLD
  26. 26. WEED CHARACTERISTICS THAT FAVOR RESISTANCE • High reproductive rate • Seed dispersal mechanisms
  27. 27. Most Important Resistant Weeds  Cyperus spp.  I. rugossum  E. crusgalli
  28. 28. HERBICIDE CHARACTERISTICS THAT INFLUENCE WEED RESISTANCE • Using herbicides with a single site of action • Use one herbicide multiple times during the growing season • Use same herbicides consecutive growing seasons • Herbicides used without other control strategies • Repeated use of a product for more than 2 years could develop a herbicide resistance problem!!
  29. 29. HERBICIDE RESISTANCE SHOULD ONLY BE SUSPECTED WHEN .……... • Other causes of herbicide failure have been ruled out • The same herbicide or herbicides with the same mode of action have been used for years • One weed that is normally controlled is not controlled while other weeds are • A patch of uncontrolled weed is spreading
  30. 30. CAUSES OF HERBICIDE FAILURES • Weed density • Moisture level • Temperature • Humidity • Rate • Application method • Organic mater content • Run off etc.. All possible reasons for poor performance should be investigated before considering the possibility of resistance!!!
  31. 31. STRATEGIES FOR CONTROL / PREVENTION • Proactive vs. reactive • Utilize other good weed control tactics • Rotate herbicides with different MOA • Rotate crops • Prevent seed production • Clean tillage and harvesting equipment
  32. 32. PROACTIVE MEASURES TO OVERCOME 1. Avoid continuous application of same AI for consecutive seasons 2. Do not mix two critical mode of action chemicals for consecutive seasons • Sulfonyl urea + ALS inhibitors • Sulfonyl urea + Sulfonyl urea 3. Avoid resistant management through increasing the dose of the chemical • 10% 20% 40% 4. Avoid mixing two incompatible formulations together • Fenoxyprp-p-ethyl + MCPA
  33. 33. 120ml70ml 100% Weed control Formulation volume 5. Always avoid underdose
  34. 34. 6. Always tank mix 02 compatible different MOA chemicals • ACCase + ALS inhi • Cell division inhi + ALSinhi • Cell divi + Photosynthesis inhi • Photosynthesis inhi+ Photo pigment inhi 7. Apply chemicals at correct time & weed stage
  35. 35. Presented: Krishan F. Motha B.Sc. Hons (Sp)

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