1. Reducing pesticide risk with Win-PST and 595
Dean P. Moberg
Resource Conservationist
USDA-NRCS
Hillsboro, OR

2. Risk assessment Labels not sufficient Monitoring expensive
Process models time consuming
Windows pesticide screening tool (Win-PST) and 595.

3. Risk assessment Labels not sufficient Monitoring expensive
Process models time consuming
Windows pesticide screening tool (Win-PST) and 595.

4. Win-PST NRCS risk screening tool. Available free (search “win pst”).
Also need to download soils data.

5. Risks Win-PST does NOT address
Worker safety
Risk to birds
Effect of soil pH

6. Risks Win-PST DOES address
Risk to humans, fish.
Groundwater leaching.
Surface water runoff
adsorbed
dissolved

7. Win-PST: soils Erodibility Slope Organic matter Leaching Surface depth
Cracking
Water table
Hydrologic group
Leaching
Dissolved runoff
Adsorbed runoff

8. Leaching potential Woodburn: low (Hydro C, 4% OM) Laurelwood: interm.
Woodburn is hydrologic group C, 4% OM, 0.37 K, 16 inch surface depth, no cracks, no high water table
Laurelwood is hydrologic group B, 3% OM, 0.37 K, 11 inch surface, no cracks, no high water table
Woodburn: low
(Hydro C, 4% OM)
Laurelwood: interm.
(Hydro B, 3% OM)

9. Dissolved runoff potential
Willamette: interm.
(Hydro B)
Wapato: high
(Hydro D)

10. Adsorbed runoff potential
If slope > 15%, adsorbed runoff potential is greater.
Jory B: interm.
(Hydro C, K = 0.20)
Delena C: high
(Hydro D, K = 0.37)

11. Win-PST: pesticides Koc Solubility Half life Leaching Toxicity
Application method
Foliar vs soil
Rate
Leaching
Dissolved runoff
Adsorbed runoff
Koc is the soil organic C partitioning coefficient. It equals the ratio of sorbed pesticide to the ratio of pesticide in solution: (g pesticide/g C) / (g pesticide/ml water)
Thus units cancel out to a ratio with units of ml water / g C
Higher Koc means more pesticide is partitioned to the soil C.

12. Leaching potential Garlon 3A = high Garlon 4 = intermediate
Half life rating 46 days
Solubility high
Koc = 20 ml/g
Garlon 4 = intermediate
Solubility low
Koc is 780 ml/g

13. Leaching potential Garlon 3A = high Garlon 4 = intermediate
Half life rating 46 days
Solubility high
Koc = 20 ml/g
Garlon 4 = intermediate
Solubility low
Koc is 780 ml/g
Koc is the soil organic C partitioning coefficient. It equals the ratio of sorbed pesticide to the ratio of pesticide in solution: (g pesticide/g C) / (g pesticide/ml water)
Thus units cancel out to a ratio with units of ml water / g C
Higher Koc means more pesticide is partitioned to the soil C.

14. Dissolved runoff potential
Transline = high
Half life rating 40 days
Solubility high
Koc = 6 ml/g
Milestone = intermediate
Half life rating 35 days
Koc = 13 ml/g
Transline is clopyralid
Milestone is aminopyralid

15. Dissolved runoff potential
Transline = high
Half life rating 40 days
Solubility high
Koc = 6 ml/g
Milestone = intermediate
Half life rating 35 days
Koc = 13 ml/g
Transline is clopyralid
Milestone is aminopyralid

16. Adsorbed runoff potential
Accord = high
Half life rating 47 days
Solubility high
Koc = 24,000 ml/g
Habitat = intermediate
Half life rating is 90 days
Koc = 100 ml/g

17. Adsorbed runoff potential
Accord = high
Half life rating 47 days
Solubility high
Koc = 24,000 ml/g
Habitat = intermediate
Half life rating is 90 days
Koc = 100 ml/g

18. Toxicity Accord (glyphosate) Habitat (imazapyr)
Human: very low (700 ppb)
Fish: low via water (MATC 168 ppb)
Fish: very low via sediment (STV > 4 x 106 ppb)
Habitat (imazapyr)
Human: very low (17,500 ppb)
Fish: very low via water (MATC 22,602 ppb)
Fish: very low via sediment (STV > 2 x 106 ppb)
Human toxicity is based on exposure adjusted toxicity classes, which is similar to EPA’s toxicity classes (for example, using LD50 concentrations for longterm ingestion, the 1 in 100,000 probability of contracting cancer for long-term ingestion).
MATC* is the maximum acceptable toxicant concentration, representing long-term toxicity of pesticides dissolved in water to fish.
STV is Koc * MATC (i.e. the max. acceptable toxicant conc in sediment for fish).

19. Toxicity Accord (glyphosate) Habitat (imazapyr)
Human: very low (700 ppb)
Fish: low via water (MATC 168 ppb)
Fish: very low via sediment (STV > 4 x 106 ppb)
Habitat (imazapyr)
Human: very low (17,500 ppb)
Fish: very low via water (MATC 22,602 ppb)
Fish: very low via sediment (STV > 2 x 106 ppb)
Human toxicity is based on exposure adjusted toxicity classes, which is similar to EPA’s toxicity classes (for example, using LD50 concentrations for longterm ingestion, the 1 in 100,000 probability of contracting cancer for long-term ingestion).
MATC* is the maximum acceptable toxicant concentration, representing long-term toxicity of pesticides dissolved in water to fish.
STV is Koc * MATC (i.e. the max. acceptable toxicant conc in sediment for fish).

20. soil rating + pesticide rating + rainfall risk
Win-PST: risk ratings
soil rating + pesticide rating + rainfall risk
Rain–Auvers (Van Gogh)

22. Soils: user adjustments
Organic matter
Surface layer depth
Slope (> 15%?)
Cracks
High water table

24. Pesticides: user adjustments
Broadcast, band, spot spray.
Soil or foliar application.
Standard, low, ultra low rate.

30. 595: NRCS Pest management worksheet
“Play” with mitigation activities.
Available free:
search “efotg” and navigate to Section IV (specifications) or

36. Azadirachtin is neem, bifenthrin is Brigade, Carbaryl is Sevin

37. Azadirachtin is neem, bifenthrin is Brigade, Carbaryl is Sevin

38. Azadirachtin is neem, bifenthrin is Brigade, Carbaryl is Sevin

41. Table describes IPM techniques and required applicator records.

42. This is next page of 595. Needed if existing IPM techniques not sufficient. Uses MCPA as example. Solution runoff risk is still red.

43. Select planned mitigation until all cells turn green.

44. Conclusions: Win-PST benefits
Easy and quick.
Consistent.
Written documentation.
Records for you.
Communication with contractors.

45. Conclusions: Win-PST cautions
Pesticide database updates (once/year?).
Few surfactants.
Bird effects not supported.
Pollinators, volatilization only partially supported.
Mitigation techniques somewhat limited.

46. A word about pH pH can influence half life and Koc.
pH often a parameter in process models such as GeoPEARL1 and MACRO.
E.g. sulfonylurea herbicides (acidic) sorb onto soil carbon more when pH low2.
Practical applications?
Van der Linden et al Influence of pH-dpendent sorption and transformation on simulated pesticide leaching. Science of the Total Environment, 407:
Brown et al Exposure to sulfosulfuron in agricultural drainage ditches: field monitoring and scenario-based modelling. Pest Management Science, 60:
1 van der Linden et al
2 Brown et al

47. No pollinators were harmed in the making of this slide show.

48. USDA-NRCS
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49. Questions