Best Practices for Ground Application

1 Pesticide Spray Drift Series—3 Parts

• March 15, 2018 webinar: “Strategies for Managing Pesticide Spray Drift” • Presented by Dr. Greg Kruger, University of Nebraska-Lincoln • Covers fundamentals of pesticide spray particle drift management • Materials available: https://www.epa.gov/reducing-pesticide-drift/strategies-managing- pesticide-spray-drift-webinar-materials

• September 27, 2018 webinar: “Best Practices for Aerial Application” • Presented by Br. Bradley Fritz, United States Department of Agriculture • Dr. Greg Kruger joined for the Q+A discussion • Webinar materials will be posted online

• Today’s webinar: “Best Practices for Ground Application” • Presented by Dr. Greg Kruger, University of Nebraska-Lincoln • Dr. Bradley Fritz will join for the Q+A discussion

4 Joining us for Q+A discussion

• Bradley Fritz, Ph.D • Agricultural engineer and Research Leader, Agricultural Research Service, US Department of Agriculture • Research areas: examining the role of spray nozzles, spray solutions, and operational settings in resulting droplet size of spray; exploring the transport and fate of applied spray under field conditions • Numerous publications: https://www.ars.usda.gov/people- locations/person?person-id=33323

5 Presenter Greg Kruger, Ph.D. • Weed science and pesticide application technology specialist • University of Nebraska-Lincoln, Department of Agronomy and Horticulture • Director of the Pesticide Application Technology Laboratory • Areas of research: droplet size and efficacy, spray drift deposition and canopy penetration, influence of nozzle type, orifice size, spray pressure, and carrier volume rate on spray droplet size • Weed Science Society of America liaison to EPA

6 Best Practices for Ground Application

Greg R. Kruger Weed Science and Application Technology Specialist WCREC, North Platte, NE

NeOiasMa I I ' 8 Definition of Drift:

Movement of spray particles and vapors off-target causing less effective control and possible injury to susceptible vegetation, wildlife, and people.

Adapted from National Coalition on Drift Minimization 1997 as adopted from the AAPCO Pesticide Drift Enforcement Policy - March 1991

9 Types of Drift:

Vapor Drift - associated with volatilization (gas, fumes) Particle Drift - movement of spray particles during or after the spray application

10 Particle Drift – Big 4

1. Wind Speed

11 Particle Drift – Big 4

1.Wind Speed 2.Boom Height

12 Particle Drift – Big 4 1.Wind Speed 2.Boom Height 3.Distance from Susceptible Vegetation

13 Particle Drift – Big 4

1. Wind Speed 2. Boom Height 3. Distance from Susceptible Vegetation 4. Spray Particle Size

14 Comparison of Nozzles

15 Relationship Between Drift and Efficacy

Efficacy

Drift reduction

16 Chemical Reactions Spray Tank Pump Shear Mixing and Agitation

Equipment Contamination Equipment/Application Atomization Physical Properties Drift Losses Atmospheric Conditions Interception by Non-targets Evaporation Volatilization Impaction Micrometerological Effects Redistribution Reflection, Shatter and Losses Spray and Surface Properties Splash Droplet Size and Kinetic Energy Retention Redistribution Run-off Dynamic Spreading Loss of Active Loss of Diluent Volatilization Spreading and Coalescence Deposit Formation Losses Weathering Absorption and Translocation Redistribution Surface Activity Pick-up and Transport to Encounter Probability Biological Effect the Site-of-Action

17 Ebert et al. 1999 TR Kochia Control 9 DAT with XR, DG, and TF Nozzles at 30 psi (2 bars) Paraquat + Atrazine (0.35 + 0.56 kg/ha)

XR Tee Jet DG Tee Jet Turbo Flood Jet

100

80

60 .3 .3 .5 .5 .25 .4 .4 .2 F C M C EC M C EC % Control 40

20 XR DG TF XR DG TF XR DG 0 10 gpa 7.5 gpa 5 gpa 94 L/ha 70 L/ha 47 L/ha 18 Carrier Volume Even at lower retention, large droplets showed uptake & translocation in RR corn

Total uptake Root translocation 60 20 48.9% Coarse dose 50 dose

15 Medium 40 35.1% 30.1% Fine • 30 10 recov'd

recov'd □ 20 Coarse (Avg 4 + SE) as % as (Avg 4 + SE) 10 Medium 5 Fine

0 Root 0 Uptake as % as Uptake 0 0.5 1 1.5 2 2.5 3 3.5 0 0.5 1 1.5 2 2.5 3 3.5 DAT after Roundup spray (32 oz/a) DAT after Roundup spray (32 oz/a)

Feng et al., Weed Science 2003 19 Impact of Nozzle Type on Droplet Retention I--" 0 0 0 )> I en 0 ■ I u, -...J 0 (µm) (thousands) I C, units n diameter I u, 0 0 ■ I w 0 mean fluorescence I N u, 0 Volume ■ I Relative 0 0 - - 20 Impact of Adjuvant on Droplet Retention

80 1000

A

vi"' "'C 60 - - 750 C: B B .,,n, ::::s 0 e .s::::. .::.. C -=... .,, QJ ·c- 1ij ::::s E QJ n, OJ C: 40 - - 500 !a QJ C: OJ n, .,, - QJ QJ - - ... E 0 - QJ ::::s - - ;:;:::: E D ::::s QJ > ~ -..:.n, cu a: 20 - E - 250

0 0 MSO NIS Sil i cone DRA NONE coc 21 Field Studies

Four locations in Nebraska Bancroft, Clay Center, Courtland, Elba Four replications per location Five planted species Amaranth, Flax, Velvetleaf, Soybean, Corn Five Nozzles plus an Untreated XR11002 (Fine), XR11003 (Fine/Medium), TT11002 (Medium), AIXR11002 (Coarse), AI11002 (Extremely Coarse)

22 Glyphosate

Amaranth 100 - ♦

90 (%) ■

Fine 80 Fine/Medium Efficacy ■ Medium Coarse Extremely Coarse ■70 ------r------.------.------.-----, 0 50 100 150 200 250 I ■ Droplet• size • (μm) • •

Creech et al. 2016 23 Dicamba

Amaranth 85 ■

■75 (%) ♦ ■ ~◊ ♦ Fine 65 Fine/Medium Efficacy Medium Coarse Extremely Coarse ■55 ------.------.------, I0 100 200 300 ---Droplet size (μm)

Creech et al. 2016 24 Fomesafen Amaranth 70 ■

60 (%) ■ ·◊ ♦ Fine 50 ♦ ♦ Fine/Medium

Efficacy ■ Medium Coarse Extremely Coarse ■40 ------r------.----~------r-----, 0 50 100 150 200 250 I ■ Droplet• size • (μm) • •

Creech et al. 2016 25 Fomesafen Flax 95 ■ . ◊

85 (%) ■

♦ Fine 75 Fine/Medium

Efficacy ■ Medium Coarse Extremely Coarse ♦ ■65 +------r------.------.------r- ~ ---, 0 50 100 150 200 250 I ■ Droplet• size • (μm) • •

Creech et al. 2016 26 Clethodim

Corn 55 ■ ◊ 45 (%) ♦ ■ ♦ Fine 35 ♦ Fine/Medium

Efficacy ■ Medium ♦ Coarse Extremely Coarse 25 ■ I0 100 200 300 ---Droplet size (μm)

Creech et al. 2016 27 Carrier Rate

• Herbicides • Soybean Management Field Day • Glyphosate (RoundUp PowerMax) – 3 GPA Locations • Glufosinate (Liberty) – 15 GPA • Lexington, NE • Lactofen (Cobra) – 20 GPA • O’Neill, NE • 2,4-D (Weedone) – 10 GPA • Platte Center, NE • Plots • David City, NE • 10’ x 30’ • Weed Control Ratings taken 14 and 28 DAT

28 Materials and Methods

Carrier Application volume Nozzle speed GPA mph 5 XR11001 4 7.5 XR11001 4 10 XR11001 4 15 XR110015 4 20 XR11002 4.8

29 Results

Velvetleaf NS 90 A A A A

B BC B 60 NS □ 5 GPA □ 7.5 GPA (%) C

□ 10 GPA C C ■ 15 GPA

Control 20 GPA 30 ■

0 2,4-D Lactofen Glufosinate Glyphosate

30 Results

Amaranth A A A NS 90 NS

60 □ 5 GPA -?fl. □ 7.5 GPA -0 ■ 10 GPA ....,'- C ■ 15 GPA 0 u ■ 20 GPA 30

0 2,4-D Lactofen Glufosinate Glyphosate

31 Lactofen 5 GPA Lactofen 10 GPA

32 300 300 2I 4-D Lactofen 100 100 250 250 - 90 E 90 ::1...... QI ~o 200 80 200 QI 0... E .... .!!! 0 u670 70 --control 150 --control 150 60 ---vMD 60 ---vMD

so 100 so 100 0 5 7.5 10 15 20 0 47 5 7.570 9410 140 15 187 20

300 300 Glufosinate Glyphosate 100 100 250 250 90 90 E ::1. ~ ... !!.. 80 200 ,2! 200 80 QI 0...... E C .!!! 8 70 70 0 150 150 --control 60 60 --control ---VMD ---vMD so 100 so 100 0 5 7.5 10 15 20 0 5 7.5 10 15 20 GPA GPA

Amaranth 33 Experimental Design

• Randomized Complete Block Design with 4 Replications • 10 inch tall Palmer amaranth • 25 Total Treatments: • 2 Carrier Volumes (5 and 20 GPA) • 6 Droplet Sizes (150, 300, 450, 600, 750, and 900 μm) • 2 Herbicides [dicamba (Clarity®) and glufosinate (Liberty®)] • 1 Nontreated Control • Applications were made using a Capstan PinPoint® Pulse-width Modulation (PWM) Sprayer • This allows for flow to be controlled by the relative proportion of time each electronically actuated solenoid valve is open (duty cycle)1 • Duty cycle was demonstrated to have minimal impact on droplet size2,3

1Giles and Comino, 1989. J. of Commercial Vehicles. SAE Trans. 98:237-249 2Butts et al., 2015. Proc. North Cent. Weed Sci. 70:111. Indianapolis, IN 34 3Giles et al., 1996. Precision Agriculture. Proc. of the 3rd International Conference. 729-738. Minneapolis, MN Nozzle type, orifice size, and application pressure combinations for each droplet size treatment. Application Herbicide Carrier volume Droplet size Nozzle pressure gal ac-1 μm PSI glufosinate 5 150 ER 110015 60 glufosinate 5 300 SR 11005 40 glufosinate 5 450 DR 11004 40 glufosinate 5 600 UR 11004 35 glufosinate 5 750 UR 11008 40 glufosinate 5 900 UR 11010 30 glufosinate 20 150 ER 110015 50 glufosinate 20 300 SR 11003 30 glufosinate 20 450 MR 11006 35 glufosinate 20 600 DR 11008 39 glufosinate 20 750 UR 11006 33 glufosinate 20 900 UR 11010 36 Butts et al. 2018 35 Nozzle type, orifice size, and application pressure combinations for each droplet size treatment. Application Herbicide Carrier volume Droplet size Nozzle pressure gal ac-1 μm PSI dicamba 5 150 ER 110015 60 dicamba 5 300 ER 11006 42 dicamba 5 450 SR 11006 35 dicamba 5 600 DR 11004 34 dicamba 5 750 DR 11008 35 dicamba 5 900 UR 11006 40 dicamba 20 150 ER 110015 60 dicamba 20 300 SR 11002 30 dicamba 20 450 MR 11004 39 dicamba 20 600 DR 11005 52 dicamba 20 750 DR 11006 38 dicamba 20 900 UR 11006 35 Butts et al. 2018 36 Best Droplet Size for Biomass % Reduction in Biomass Carrier Volume Reduction from Control 5 GPA 150 μm 80 Dicamba 20 GPA 600 μm 73 5 GPA 300 μm 93 Glufosinate 20 GPA 450 μm 80

• Glufosinate: • For both carrier volumes, 750 and 900 μm droplets were not different from nontreated control for biomass reduction • Dicamba: • For both carrier volumes, 900 μm droplets were not different from nontreated control for biomass reduction

Butts et al. 2018 37 GAM Model for droplet size and carrier volume effect on Palmer amaranth control

Glufosinate • • 4 57.5% Deviance Explained •

•

(J) (J) ro E 0 Zi >- "O 2 -0 • Ol _Q

• • • Carrier volume: 5 GPA -20 GPA 0 - 5.0 5.5 6.0 6.5 Natural log of droplet size(µ m) __:I Butts et al. 2018 p 38 Control 150 μm 300 μm Glufosinate

5 GPA

14 DAA

450 μm 600 μm 750 μm 900 μm

Butts et al. 2018 39 GAM Model for droplet size and carrier volume effect on Palmer amaranth control

Dicamba

4 • •

(/) (/) co E 0 :15 >, "O 0 2 0) .Q

~ ::::, -zco

• Carrier volume: 28.0% Deviance Explained 5 GPA - 20 GPA • - 250 500 750 Butts et al. 2018 Droplet size (µ m) 40 Control 150 μm 300 μm Dicamba

5 GPA

14 DAA

450 μm 600 μm 750 μm 900 μm

Butts et al. 2018 41 Optimum droplet sizes for maximum Palmer amaranth control

Dicamba Glufosinate

5 GPA 150 μm Fine 270 μm Medium Extremely 20 GPA 626 μm 488 μm Very Coarse Coarse

Butts et al. 2018 42 Tank Mixtures on Weed Control

• horseweeda, [Conyza canadensis (L.) Cronq] • kochiaa, [Kochia scoparia (L.) Schrad.] • common lambsquarters, (Chenopodium album L.) • grain sorghum, [Sorghum bicolor (L.) Moench subsp. bicolor.] aResistant to glyphosate

43 Treatments

Common name Treatment rate Glyphosate (Roundup PowerMax®) 600 g ae ha-1

Lactofen (Cobra®) 110gaiha-1

Fomesafen (Flexstar®) 65 g ai ha-1

Ammonium Sulfatea 17 lb/100gal

80% Crop oil concentrateb 1% v v-1

aAmmonium sulfate (AMS) was added to all treatments. bCrop oil concentrate (COC) was added to all treatments except for glyphosate applied alone.

44 Nozzle Selection

Common Name Nozzle Typea DRT Featureb Extended Range XR None

Air-Induction Extended Range AIXR Venturi, pre orifice • Venturi, pre orifice, anvil Turbo Teejet Induction TTI shaped

Venturi, pre orifice, off-set Guardian air GA angle

Venturi, pre orifice Ultra Lo-Drift ULD

Dual cap, venture, pre- TurboDrop® XL TDXL orifice aThe listed nozzle types were all orifice size “04” with a manufacturer-rated spray plume angle of 110° except for ULD nozzles that were 120°. bDrift reduction technology feature.

45 Herbicide Applications

Treatments were sprayed at:

• 187 l ha-1

•9.6kph

Nozzles spaced 50 cm • 276 kPa apart and at 50 cm above the plants.

Three-nozzle research track sprayer.

46 Results

ANOVA results based on biomass reduction at 28 DAT.

Type III Tests of Fixed Effects Effect Num DF F Value Pr-valuea Herbicide solution 4 109.43 <.0001 Nozzle 5 1.08 0.3688 Herbicide solution*Nozzle 20 0.88 0.6164 Species 3 632.04 <.0001 Herbicide solution*Species 12 166.74 <.0001 Nozzle*Species 15 0.89 0.5708 Herbicide solution*Nozzle*Species 60 1.09 0.3900 aSignificant value (3”).

47 Droplet spectra

Spray-droplet distributiona XR GA AIXR

b b b b b b Dv0.5 ”—m CCc Dv0.5 ”—m CCc Dv0.5 ”—m CCc Herbicide solution (μm) (%) (μm) (%) (μm) (%)

Glyphosate + AMS 240t 21.30a F 397r 5.35d C 487l 3.13g VC

Lactofen + AMS + COC 268s 12.05c M 443o 2.24i VC 481m 1.68j VC

Fomesafen + AMS + 265s 12.14c M 432p 2.31i VC 473n 1.70j VC COC l l

Glyphosate + Lactofen + 269s 11.96c M 393r 3.39f C 471n 1.83j VC AMS + COC

Glyphosate + Fomesafen 266s 12.37b M 409q 2.69h C 444o 3.81e VC + AMS + COC l l a Dv0.5 represents the droplet size such that 50% of the spray volume is contained in droplets of equal or lesser values. bMeans within a column followed by the same letter are not statistically different (3”). cThe classification category for this study was made based on reference curves created from reference nozzle data at the PAT Lab as described by ASAE 572.1 where F = fine, M = medium, C = coarse, VC = very coarse, XC = extremely coarse, and UC = ultra coarse.

48 Droplet spectra

Spray-droplet distributiona TDXL ULD TTI

b b b b b b Dv0.5 ”—m CCc Dv0.5 ”—m CCc Dv0.5 ”—m CCc Herbicide solution (μm) (%) (μm) (%) (μm) (%)

Glyphosate + AMS 505j 3.08g VC 610f 1.06l,m XC 787a 0.52q UC

Lactofen + AMS + COC 540h 1.04l,m XC 624e 0.71n,o,p,q XC 653c 0.58p,q XC

Fomesafen + AMS + 527i 1.17l VC 602g 0.70n,o,p,q XC 640d 0.60o,p,q XC COC l □l □l Glyphosate + Lactofen + 500j 1.41k VC 609f 0.81n,o XC 613f 0.76n,o,p XC AMS + COC

Glyphosate + Fomesafen 504j 1.24l,k VC 610f 0.85n,m XC 754b 0.50q UC + AMS + COC l Dt Dt a Dv0.5 represents the droplet size such that 50% of the spray volume is contained in droplets of equal or lesser values. bMeans within a column followed by the same letter are not statistically different (3”). cThe classification category for this study was made based on reference curves created from reference nozzle data at the PAT Lab as described by ASAE 572.1 where F = fine, M = medium, C = coarse, VC = very coarse, XC = extremely coarse, and UC = ultra coarse.

49 Driftable fines

- XR - AIXR - TTI - GA - TDXL - ULD 25 E :::1. 0 It) .... 20 VI !/) -Cl) C. 15 ...0 't:J .... 0 El Cl) E 10 ::I 0 > C: 5 -Cl) ...CJ Cl) a. 0 Lactofen Fomesafen Glyphosate Glyphosate + Glyphosate + Lactofen Fomesafen Solutions

50 Colby’s Equation

• The responses of herbicides applied singly are used in calculating the “expected” response when they are applied in combination (Colby 1967)

51 Colby’s Equation (X Y ) E = 1 1 1 100

•X1 = 100 – X (X = observed response by herbicide A)

•Y1 = 100 - Y (Y = observed response by herbicide B)

•E1 = 100 – E (E = expected response by herbicides A + B)

52 Example

Control (%) Herbicide Observed Expected A 30 Synergistic B 50 interaction A + B 80

(ହ଴כଡ଼ ଢ଼ ) (଻଴) E = ଵ ଵ = =35 1 ଵ଴଴ ଵ଴଴

E = 100 െ 35 = 65

53 Example

Control (%) Herbicide Observed Expected A 30 Additive B 50 interaction A + B 65

(ହ଴כଡ଼ ଢ଼ ) (଻଴) E = ଵ ଵ = =35 1 ଵ଴଴ ଵ଴଴

E = 100 െ 35 = 65

54 Example

Control (%) Herbicide Observed Expected A 30 Antagonistic B 50 interaction A + B 42

(ହ଴כଡ଼ ଢ଼ ) (଻଴) E = ଵ ଵ = =35 1 ଵ଴଴ ଵ଴଴

E = 100 െ 35 = 65

55 Tank-mixture Interactions

Horseweed Kochia

Controla (%) Controla (%) Herbicide Solution Observedb Expectedc CI (%) Observedb Expectedc CI (%)

Glyphosate + AMS 26.8 c 21.9 d

Lactofen + AMS + COC 53.0 a 91.9 a

Fomesafen + AMS + COC 39.5 b 84.7 b

Glyphosate + Lactofen + 42.0 b - 92.9 a - AMS + COC

Glyphosate + Fomesafen + 38.1 b - 77.0 c - AMS + COC l a Percentage of control based on the biomass reduction at 28 DAT. b 0HDQVZLWKLQDFROXPQIROORZHGE\WKHVDPHOHWWHUDUHQRWVWDWLVWLFDOO\GLIIHUHQW 3”  c Expected values were calculated as described by the Colby equation (1967); an asterisk adjacent to the expected control indicates antagonism.

56 Untreated Untreated

Glyposate + Fomesafen Fomesafen Tank-mixture Applied alone

At 14 DAT

57 Tank-mixture Interactions

Common lambsquarters Grain sorghum

Controla (%) Controla (%) Herbicide Solution Observedb Expectedc CI (%) Observedb Expectedc CI (%) Glyphosate + AMS 92.6 a 98.4 a I

Lactofen + AMS + COC 63.2 c 50.9 b Fomesafen + AMS + COC l72.9 b l49.7 b Glyphosate + Lactofen + 89.0 a - 97.2 a - AMS + COC

Glyphosate + Fomesafen + 90.4 a - 96.9 a - AMS + COC l l a Percenta ge of control based on the biomass reduction at 28 DAT. b 0HDQVZLWKLQDFROXPQIROORZHGE\WKHVDPHOHWWHUDUHQRWVWDWLVWLFDOO\GLIIHUHQW 3”  c Expected values were calculated as described by the Colby equation (1967); an asterisk adjacent to the expected control indicates antagonism.

58 Tank-mixture Interactions • Combination of glyphosate and fomesafen or sulfentrazone caused reduced efficacy of both herbicides (Starke and Oliver 1998)

• Flumiorac was antagonistic to glyphosate in Palmer amaranth (Nandula et al. 2012) 1 • Reduction of glyphosate absorption and translocation

59 Take Home Messages! C Particle drift can be influenced by formulation 7 C Nozzle selection has the greatest influence on particle size 7 C Adjuvants can reduce drift potential, but must be tested 7 C There is no substitute for common sense – if the wind is blowing droplets will move 7 C Pay attention to sensitive vegetation in surrounding areas 7 Drift WILL happen! Mitigating drift is essential! C 7 60 Questions?

• Greg Kruger • Cropping Systems Specialist • West Central Research and Extension Center • North Platte, NE • Website: pat.unl.edu • [email protected] • (308)696-6715

• Thank You!

61 ? w f'I, 1 whel\ who h-~f-why 7 - Swh~ how where- -who hy OW 7 whe

68