Precision Electronic Dispenser for Application of Herbicide Sprays and Foam

1. Precision Applications of Herbicide Spray and Foam John Lampe Coeur d'Alene, IdahoDecember 12, 2019 Innovations in Invasive Species Management

2. Most herbicide spray technologies have been adapted from agriculture. .

3. Precision herbicide application not important with genetically-modified, herbicide-resistant corn. Corn WeedsWeeds

4. Native area management is different.

5. Native plants are not herbicide resistant.

6. Native plants are valuable: • Forbs can live 3-25 years • Grasses can live 5-39 Laurenroth et al. 2008.

7. For native area management “Transfer efficiency” is key: 1. target just the weed. 2. Keep the herbicide on the weed. 3. in the best form for absorption.

8. Compare transfer efficiency between: • Agricultural herbicide spray techniques • Green Shoots technology: • Foam herbicide • Ultra-low-pressure spray

9. Agricultural Spray Technology “Transfer efficiency”: 1. target just the weed. 2. Keep the herbicide on the weed. 3. in the best form for absorption.

10. Agricultural Model Uses High Pressure Spray

11. As Pressure Increases Drop Size Decreases “A simple rule that holds for all nozzles.” Bete Fog Nozzle, Inc.

12. Well known: small drops are drift prone and reduce ability to target.

13. Drift Studies with Backpack Sprayers – A Few • Snelder et al. (2008): • 0.5 m from field boundary, drift was 12% of applied dosage • 1.5-2.0 m from field boundary, drift was 2% • De Snoo et al. (1993): • 0.6 m downwind from field, drift was up to 10% • 0.9 m downwind from field, drift was up to 3% • Thistle et al. (2017): • 2 m downwind from swath, drift was 1%

14. Ideal study? • One that accounts for the entire volume released from a spray nozzle • For example: • 80% in the target area • 20% beyond target area • No study in the field comes close to that yet.

15. This case study looks at how high pressure affects spray coverage closer to the target area. This is critical when doing spot spraying among desirable species.

16. Theoretical spray coverage D Spray angle This illustration resembles ones in technical guides for nozzles. nozzle Actual spray coverage

17. For agricultural spraying, there’s overlap of spray patterns.

18. White paper Walking Direction Spray Coverage Centerline To explore spray coverage, we did indoor tests where we sprayed colored water onto white paper.

19. 10 in. White Paper The nozzle was held at a constant height of 10 in. Pressure was at 5 to 30 psi. Measured this distance Center Line

20. Theoretical Spray Coverage Area for Hypro VP-110-015 At 30 psi, many drops are deposited well beyond the “theoretical spray coverage area.” Center Line

21. 14.0 in. >35 in. At 30 psi, the “shadow spray coverage” extends more than 35 in. from the center line. 10 in. Nozzle: Hypro VP-110-015. ?

22. Hypothesis: the spray pattern is affected by the ground or other objects. Smaller lower velocity drops Smaller lower velocity drops

23. This big “shadow” spray coverage area may put nearby desirable plants at risk.

24. You may think you are avoiding the desirable plant in the middle.

25. Given the potential for off-target harm. . . Why does agriculture prefer high pressure?

26. Why preferred for agriculture? Generally, herbicide performance increases as droplet size decreases at constant tank volume. Knoche 1994.

27. Why might small drops perform better?

28. Agricultural Spray Technology “Transfer efficiency”: 1. target just the weed. 2. Keep the herbicide on the weed. 3. in the best form for absorption.

29. Small drops are generally retained better on leaves. Yao et al. 2014.

30. Traditional Agricultural Spray Technology “Transfer efficiency”: 1. target just the weed. 2. Keep the herbicide on the weed. 3. in the best form for absorption.

31. “300 μm diameter droplets had longer evaporation times per droplet volume and greater wetted area per droplet volume than the 600 μm diameter droplets.” Xu et al. 2010. 300 μm Drops 600 μm Drop Coverage area + wetted time Volume

32. For transfer efficiency with traditional agricultural methods: 1. target just the weed. 2. Keep the herbicide on the weed. 3. in the best form for absorption. Bad Pretty good

33. Green Shoots products use foam and spray technology to increase “transfer efficiency.”

34. Precision Electronic Dispenser for Foam and Spray Power Cap

35. Custom Backpack Frame

36. Ultra-low pressure •Pressure range: 1.5 psi to 12 psi. • Foam: 1.5 to 10 psi. • Foliar spray: 5 to 12 psi. • Basal spray: below 5 psi. • Increments of 0.2 psi.

37. Power Cap Lithium-ion battery: highest grade Panasonic® cells provide all day power. Rugged Handle: secure hold for carrying and opening tank. Power Switch: recessed to prevent inadvertent activation; blue light indicates “on.” Charging Port: easy access for power cord. www.greenshootsonline.com 37

38. Pressure Release: brass knob for easy grip. No-Drip Shut-Off: minimizes harm to non-target organisms. Anti-Kink Supports: prevent hose kinking at stress points. Thick Wall High Density Poly Tank: Absorbs abuse. Brass and Stainless Steel: Add strength at wear points. Nozzle: compatible with best nozzle tips from Hypro® Lechler® and TeeJet®. Other Features 38

39. Manual Foam Herbicide Dispensers

40. Foam Herbicide Technology “Transfer efficiency”: 1. target just the weed. 2. Keep the herbicide on the weed. 3. in the best form for absorption.

41. 12 days later. First, you can target just the weed with a low-volume-high-concentration application.

42. Low-volume-high-concentration applications: • Low carrier volume • High concentration of herbicide (typically above 2% a.i.)

43. Application to toadflax.

44. Application to cut-stem of thistle

45. Dead Canada thistle – early July application at Friends of Mississippi site.

46. Foam herbicide applied to a cut tree stem.

47. Electronic Dispenser with mesh brush attachment

48. Mesh brush with Large Handheld Dispenser

49. Stump applications using Electronic Dispenser and mesh brush

50. Foam herbicide applied to notches.

51. Effective

52. Large Foam Herbicide Dispenser with foliar nozzle.

53. Minnesota Dept Agriculture - application to Japanese knotweed.

54. Even this foliar application can be quite precise.

56. Foam can really keep herbicide on the weed.

57. Phragmites Application

58. Foam slides down grassy stems.

60. Minimal coverage, but application is very effective.

61. Even a tiny amount of glyphosate can do the job even though coverage is limited.

62. How can this be in light of Knoche? • Glyphosate is different. Low-volume-high-concentration applications have been found more effective. Cranmer et al. 1991; Feng et al. 1994. • Other low-volume-high-concentration application methods have been found highly effective using a variety of herbicides. • Drizzle technique: • DiTomaso 2016 (“drizzle” technique using concentrated triclopyr ester and surfactant). • Motooka et al. 2002 (Hawaii weed control guide including “drizzle” technique) • Splatter technique: • Brooks et al. 2014(aminopyralid/fluroxypyr, fluroxypyr and metsulfuron-methyl • to Siam weed). • Herbicide Wiping: • Harrington et al. 2016. (“Despite huge potential . . . only limited research.”) • Surfactants: Surfactants can improve results, potentially even for herbicides other than glyphosate as DiTomaso suggests.

63. For transfer efficiency using foam herbicide: 1. target just the weed. 2. Keep the herbicide on the weed. 3. in the best form for absorption. Improve At least maintain

64. What about a spray application system?

65. Ultra-Low- Pressure Spray Technology

66. Ultra Low- Pressure Spray Technology “Transfer efficiency”: 1. target just the weed. 2. Keep the herbicide on the weed. 3. in the best form for absorption.

67. 10 psi 30 psi 14 in. 18 in. 14 in. >35 in. Smaller shadow spray coverage area mean less off-target spray.

68. 9 psi 30 psi Bigger drops mean less drift.

69. 71 Ultra-Low Pressure : 3 psi With basal bark applications, you will get a consistent narrow stream at ultra-low pressure!

70. A lot of this applied herbicide is going to waste because of high pressure. Low pressure can reduce this waste. In calibrating our PED, we spray around 3-5 gallons per acre vs. 10-15 common with pump backpacks. Herbicide Waste

72. First, reducing the velocity of drops improves retention. Yao et al. 2014. Lower pressure creates lower velocity drops

73. Second, surfactants will help larger drops stick better to leaves.

74. Instead of bouncing off the leaf . . .

75. The drop sticks with added surfactant.

76. A 306 micron drop bounced off a leaf more than 50% of the time when pure water was used and bounced 0% when a surfactant concentration of 0.75% was used. Dong et al. 2015.

78. 30 psi – Glyphosate 4% ai; no surfactant; Hypro® 30HCX8 nozzle tip 5 psi – Glyphosate 4% ai; no surfactant; Hypro® 30HCX8 nozzle tip Given how glyphosate performs, the application at left might perform better than the one at right.

79. But . . . let’s assume you want better coverage than this.

80. Coverage can be adjusted to the desired level using surfactants.

81. No surfactant. 5 psi 10 psi 30 psi

82. With Surfactant – 0.5% a.i. alkyl polyglucoside (no anti-foam) 5 psi 10 psi 30 psi

83. 85 10 PSI 30 PSI www.greenshootsonline.com

84. For transfer efficiency using ultra-low-pressure spray: 1. target just the weed. 2. Keep the herbicide on the weed. 3. in the best form for absorption. Improve At least maintain

85. John Lampe: •Email: john@greenshootsonline.com •Cellphone: 651-245-4682 •Website: www.greenshootsonline.com