Reeves Petroff MSU Extension Pesticide Education Specialist

1. Knowledge, Information & Links Reeves PetroffMSU ExtensionPesticide Education Specialist http://mtpesticides.org

2. Water Quality & Pesticide Performance

3. How water quality affects certain pesticides Goal • Minerals • pH • Dirty Water

4. How water quality affects certain pesticides Goal • Weak acid herbicides • Insecticides • Organophosphates • Carbamates

5. + + + + H H H H O O - - Water - Covalent Bonds – shared electrons pH of 7 = neutral • Universal Solvent – Dissolves & attracts many substances

6. Hydrological Cycle Adds minerals and pH to water CO2 + H20 = carbonic acid Carbonate CO3Alkaline Bicarbonate HCO3Alkaline Minerals

7. Water Primary diluent New Term • Why water quality is important! • 1 pint or 1 quart per acre • 30 GPA application volume • 99% and 93% of spray solution

8. Minerals Hard Water

9. Total Dissolved Solids ppm grains * 17 ppm per grain TDS

10. Positive Charge (cations) Negative Charge (anions) Calcium (Ca++) Sulphate (SO4-) Magnesium (Mg++) Chloride (Cl -) Sodium (Na+) Bicarbonate (HCO3-) Common mineral elements in Montana water Ions - Charged atoms nitrate (NO3-) potassium (K+) iron (Fe++, Fe+++),

11. ppm/Gal Grains/Gal Soft 0 - 60 0 – 3.5 Mod. Hard 60 - 120 3.5 – 7.0 Hard 120 - 180 7.0 – 10.5 Very Hard Over 180 Over 10.5 Reference: Montana Environmental Health Association – Sanitarian’s Field Guide What is hard water?

12. How is TDS measured? Calcium = 666 ppm Sulphate = 2434 ppm Magnesium = 234 ppm Chloride = 32 ppm Sodium = 130 ppm Bicarbonate = 346 ppm • Weight • EC • Chemical reaction (Test Strips) 3842 ppm. TDS > 500 mg/L (ppm) is salty to taste

13. Types Of Water •  Drinking water <500 TDS (EPA) •  Fresh Water : <1,000 TDS •  Brackish : 1,000-5,000 TDS •  Highly Brackish : 5,000-15,000 TDS •  Saline : 15,000-30,000 TDS •  Sea Water : 30,000-40,000 TDS •  Brine : 40,000-300,000+ TDS

16. Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Understanding Water HardnessWater Softening – Ion Exchange • Resin Beads • anionic (-) • hold cations(+)

17. Mg++ Ca++ Na+ Ca++ Na+ Mg++ Mg++ Na+ Mg++ Na+ Na+ Mg++ Flow Ca++ Na+ Mg++ Ca++ Mg++ Na+ Na+ Ca++ Na+ Ca++ Na+ Na+ Ca++ Na+

18. Glyphosate(Roundup) use rate Maximum Water Hardness Grains/US gal. ppm CaC03 equivalent Low Rates for Annual Grass Weeds 20 350 Higher rates for Perennial Weeds 40 700 Water Quality Effects on Herbicides Hard Water

19. Weak Acid Herbicides • Most affected by hard water and pH • Acids release H+ ions in water • Weak acids release H+ slightly Glyphosate – Roundup Paraquat – Gramoxone Clethodim – Select Sethoxydim – Poast Many 2,4-D products

20. C-O- C C-CH3 C Weak Acid Herbicides CH3 |+NH2 | CH3 Dissociation – splitting of the molecule

21. C-O- C-O- C C C-CH3 C-CH3 C C Weak Acid Herbicides CH3 |+NH2 | CH3 +Ca+

22. - Herbicide molecule - • Penetrate the target weed intact • Travel to the site of action • Kill the plant.

23. CH3 |+NH2 | CH3 C-O- C C-CH3 C Intact molecule = more plant penetration

24. Water pH & Herbicides What is pH? • Measures H+ ions • potential Hydrogen • More H+ = lower pH = more acid

25. Logarithmic

26. pH and Herbicides • Acidic conditions for most herbicides • pH 3 to 6 • Lower pH avoids dissociation • The exceptions • Ally • Escort • Read the label

27. C-O- C C-CH3 C pH Hard Water High pH = dissociation Molecule is vulnerable CH3 |+NH2 | CH3 +Ca+

28. Bicarbonate Waters • Associated with sodium • > 500 ppm & high pH • Affects 2,4-D • Affects “dim” herbicides • Poast - sethoxydim • Select – clethodim • Achieve -tralkoxydim

29. …dim herbicides

31. Bicarbonate Waters- Solution - • Use maximum allowed rate • Apply during optimal growth stage • Adjuvants • - Non-ionic Surfactant (NIS) • - Acidifiers/buffers

32. Total Suspended SolidsTSS Water Quality Effects on Herbicides Turbidity • diquat (Reglone, Reward) • paraquat (Gramoxone) • glyphosate (Roundup, Touchdown, etc. Dirt Organic MatterOM

33. Water Quality Effects on Herbicides • Binds the herbicide + + Roundup ++ - - OM -- Herbicide not absorbed • Clogs screens • Pumps?

34. Filters Settle basin TSS – Solutions • Clean water supply • Filtering

35. pH & Insecticides • Organophosphates • Malathion • Parathion • Carbamates • Sevin

37. Solutions? 1. Test the water • Test strips • Meters • Labs

38. Test strips • Easy to use • Cheap - $8 to $20 • Some combine ph & hardness • Improved accuracy

39. Meters pH, EC, TDS $179.00 • Accurate • Calibrated • $100 + www.gemplers.com

40. Labs • Collection guidance • Tests performed • How to interpret results • $50 – $100+ http://mtpesticides.org  Links  Labs

41. Less ions present • Example: • 25 to 15 GPA • Only if practical • pH still a problem • Label? 1. Test the water 2. Reduce Water Volume

42. More pesticide ions present • More costly • Non-target damage? 1. Test the water 2. Reduce Water Volume 3. Use maximum allowed rate

43. Mix what you need • Smaller areas • Planning • Scouting • Good notes 1. Test the water 2. Reduce Water Volume 3. Use maximum allowed rate 4. Spray ASAP after mixing

44. 1. Test the water 2. Reduce Water Volume 3. Use maximum allowed rate 4. Spray ASAP after mixing 5. Adjuvants

45. pH HardWater Adjuvants • Additives to improve performance • Acidifiers • Buffers • Conditioners • Ammonium Sulfate (AS) • Non-ionic surfactants (NIS) www.herbicide-adjuvants.com