1. Initial Identification of Issues with Spray Coverage in south Georgia Blueberries
Renée Allen
Area Blueberry Agent
Extension, Alma, GA
Dr. Glen Rains, P.E.
Department of Entomology
Dr. Phil Brannen
Department of Plant Pathology

2. Growing Concern Regarding Spray Coverage & Efficacy
Wide range of sprayers available but not much data…which is the best?
What kind of coverage are we getting and is it efficacious?
Pest location?
Exobasidium
Spotted Wing Drosophila
Pathogens in different locations (in buds, soil, etc.)
SWD hangs out under leaves during hot days?

3. Goals for Field Day
Compare coverage among commercial and grower-modified sprayers
Determine spray coverage in blueberry canopy with operator’s current settings
Assess droplet size at different locations and orientations within canopy
Consider what spray coverage and droplet size data mean with regards to control of various pests

4. Vision Pink Foam Marker Dye placed in each sprayer’s tank
Temperature, humidity, wind speed/direction recorded
Operator ran sprayer
Poles holding Kromekote cards captured droplets V
B F
Top
Bot H L2 L1 R1 R2 Hi
Med
Low Hi
Med
Low
L1 and L2 – Left side bushes with collection cards
R1 and R2 – Right side bushes with collection cards
B – Back card
F – Front Card
Top – Top Card
Bot – Bottom Cards
Hi – highest measurement
Med – mid height measurement
Low – Lowest measurement
V – Vertical Card
H – Horizontal Card
Tractor View

6. Airblast Sprayer Top View Sprayer Direction R2 R1 R3 R4 Canon Sprayer
Airblast Sprayer
Top View
Sprayer
Direction R2 R1 R3 R4
Canon Sprayer
Top View L2 L1 R1 R2
Sprayer
Direction

7. Airblast Sprayer Wind 5.7 mph L1 R1 L1 Tractor View V: 4.4%, 321 VMD
HB: 4.4%, 280 VMD
HB: 21.1%, 383 VMD
V: 10.1%, 353 VMD L1 R1
V: 27.0%, 514 VMD L1
H: 2.5%, 263 VMD
V: 13.4%, 343 VMD
H: 1.6%, 201 VMD
V: 29.7%, 398 VMD
V: 32.9%, 547 VMD
H: 12.4%, 224 VMD
H: 5.5%, 281 VMD
Tractor View

8. Airblast Sprayer Wind 5.7 mph L2 R2 Tractor View V: 15.7%, 320 VMD

9. Airblast Airblast Sprayer
Good coverage high, middle, and low heights in plants in rows beside sprayer
Wind greatly affected coverage on 2nd row over from sprayer
2nd row over in direction of wind had more coverage
2nd row over not in direction of wind had very little to no coverage
Wind speed 5.7 mph

10. Cannon Sprayer R4 R3 R2 R1 * * Row 1 Row 2 Row 3 Row 4 * *
May be good for systemic or going down every other row?
Row 1
Row 2
Row 3
Row 4

11. Cannon Sprayer
Good coverage top of first row, top to middle of 2nd row, really good coverage middle to bottom of 3rd row, and little bit of coverage bottom of 4th row
May be good for going down every other row
May be good for application of systemic pesticides (cover multiple rows quickly)

12. Boom Sprayer
Boom sprayer L2 C R1 R2
Sprayer
Direction

13. R2
4.9%, 539
66.2%, 0
2.5%, 434
0.14%, 276
1.3%, 316
38.2%, 633 L2
13.1%, 575
13.5%, 481
7.1%, 340
1.6%, 253
4.8%, 217
1.3%, 264

14. R1
4.5%, 263
24.4%, 492
16.4%, 580
13.2%, 464
10.0%, 290
0.2%, 246 C
0.2%, 186
3.6%, 334
5.9%, 350
7.2%, 348
2.1%, 301
1.0%, 260

15. 18”
Object to be sprayed should be like 1 ft above object to be sprayed

16. Alternate Row Middle Study
*Tim Varnedore (Jeff Davis county ag agent): not pictured

17. V 2’ 2’ B F Top Bot H I1 O1 O2 I2 Hi Med Low Tractor View
L1 and L2 – Left side bushes with collection cards
R1 and R2 – Right side bushes with collection cards
B – Back card
F – Front Card
Top – Top Card
Bot – Bottom Cards
Hi – highest measurement
Med – mid height measurement
Low – Lowest measurement
V – Vertical Card
H – Horizontal Card
Med
Low
Tractor View

18. 2 mph
Airblast Sprayer
Top View
Sprayed from left side only
62 GPA I1 O2 I2 O1
Tractor
Direction – 3 mph

19. Airblast Sprayer I2 O2 O1 I1 I1 I2 Tractor View *13.0%, 259 15.5%, 316
*47.9%, 684
31.5%, 475
64.1%, 0
*17.4%, 403
18.5%, 257
18.2%, 265
97.9%, 0
70.5%, 0
70.1%, 0
77.4%, 0
Tractor View

20. I1 O2 I2 O1
0.02%, 106
2.0%, 214 O1
0.06%, 73
3.3%, 168 O2
0.07%, 97
4.3%, 246
0.27%, 327
11.8%, 268
Wind was blowing in that direction towards 02 so heavier droplet coverage
2.7%, 154
11.2%, 245
6.8%, 186
3.3%, 238

21. Alternate Row Middle Results

22. Conclusions Wide variation on droplet size and coverage among sprayers
Cards close to nozzles have large droplets
Wind speed can have a significant effect, especially further away from sprayer
High pressure produces a lot of small droplets that can produce drift
Alternate row middle spraying tremendously limits spray coverage on rows sprayer does not travel down
Big droplets can actually be repetitive hits that accumulate from small droplets hitting it multiple times

23. Next Steps Initiate research projects
Choose 2 or 3 sprayers
Conduct efficacy studies in spring for control of SWD
Test different chemistries & rates
Conduct sprayer calibration workshop
Early February
Review possible issues with sprayer nozzles such as wear, pressure, speed, placement
Green leaf air induction nozzles boom sprayer that’s vertical on both sides
This works and this is the type of coverage so then compare to your particular sprayer

24. Blueberry Specialists
Dr. Glen Rains (ag engineer)
Dr. Phil Brannen (pathologist)
Dr. Ashfaq Sial (entomologist)
Dr. Erick Smith (horticulturalist)
Dr. Dan Horton (entomologist)
Blueberry Farmers
Retired UGA Ag Agents
Danny Stanaland (Four Seasons Consulting)
John Ed Smith (MBG)
James Clark (Southeastern Gin & Peanut)
County Agents
James Jacobs (Pierce/Ware)
Benjamin Shirley (Bacon)
William Lovett (Brantley/Charlton)
Jeremy Taylor (Lanier/Clinch)
Tim Varnedore (Jeff Davis)
Sponsors
Bennett’s Tractor Service
Crosby Equipment Company
BASF
Crop duster pilot Shelton Souther
We also had retired agents there who were extremely supportive: Danny Stanaland (Four Seasons Consulting), John Ed Smith (MBG), & James Clark (Southeaster Gin & Peanut)