Sprayer prescriptions for protectant sprays on spring canopies Robyn Gaskin, Dave Manktelow, Bill May, Kevin Steele & Rebecca van Leeuwen

- 3 trials; Atom 2000 Turbo sprayer on post-harvest AUTUMN canopies - Trial 1: WSPs, 6 sprayer setups (AI-FF, AI-HC, ATR-HC, Article 58) - Trial 2: WSPs, 9 sprayer setups (ATR-HC, Article 58… & AI-FF) - Trial 3: measured deposits, 6 sprayer setups (ATR-HC, Article 58)

Atom Sprayer, front entry fan, 3.8 m rows Coverage potential as good as it gets?

Water sensitive paper (WSP) setups; in-canopy and plume height Upper & lower surfaces WSPs Pinned “in canopy” on top & bottom surfaces of leaves - upper, mid, lower canopy X row centre, leader zones WSPs mounted on poles at 1m intervals, 1-5 m high in leader zone

Hayward, post-harvest light autumn canopy, late May

ATR (fine HC) nozzles 400 L/ha, 100 ml adj/100L 6 km/h I= <10%, R= <10% Article 58 (HC) nozzles 1000 L/ha, 40 ml adj/100L 6 km/h I= 10%, R = 60% Article 58 (HC) nozzles 1000 L/ha, water 6 km/h Inadequate= <10%, Runoff= 30%

Water sensitive paper assessments WSPs do not show spray coverage on surfaces ! Each droplet contains the same volume WSP Hayward Leaf top surface No adjuvant Du-Wett 50 ml/100 L Du-Wett 100 ml/100 L mm mm 2

WSP comparisons Dilute spray e.g 800 L/ha, no adjuvant 2x concentrate spray e.g. 400 L/ha ml adjuvant Run-off Excellent Inadequate?? Each droplet contains 2x more chemical! and will spread 10x more on leaf surface

ml adjuvant/100 litres Spread area (mm 2 ) Performance of wetters & spreaders used in CPP: spreading on a difficult-to-wet leaf

STUDY 3: deposits (Hayward) Tmt # NozzlesSpray volu me Air outputTravel speed (L/ha)(m 3 /h)(km/h) 1*Article moderate6.0 2ATR600moderate6.0 3ATR400moderate6.0 4ATR400low6.0 5*ATR400high6.0 6ATR400high7.5 * Single leaf side deposits also measured 2 nozzle types, 3 spray volumes, 3 fan speeds, 2 travel speeds, All tmts contained Du-Wett at 400 ml/ha ( ml/100L)

All tmts contained Du-Wett adjuvant: 400 ml/ha b a Mean deposits on foliage a b b b CONTROL

All tmts contained Du-Wett adjuvant: 400 ml/ha abc a Mean deposits on foliage in upper/lower canopy zones ab bc c c d f d ef de CONTROL

All tmts contained Du-Wett adjuvant: 400 ml/ha b a Mean deposits on foliage in centre row and leader zones a bbcd b cd d bc cd bcd cd CONTROL

All tmts contained Du-Wett adjuvant: 400 ml/ha Mean deposits on foliage in all canopy zones CONTROL * * * * sig. diff. to control * * *

All tmts contained Du-Wett adjuvant: 400 ml/ha c Mean deposits on single leaves a c CONTROL = 40 ml/100 L DW b #5 = 100 ml/100 L DW

All tmts contained Du-Wett adjuvant: 400 ml/ha Mean deposits on single leaves: top surfaces only CONTROL = 40 ml/100 L DW #5 = 100 ml/100 L DW

All tmts contained Du-Wett adjuvant: 400 ml/ha Mean deposits on single leaves: bottom surfaces only CONTROL = 40 ml/100 L DW #5 = 100 ml/100 L DW a b bc bcd cd d

Surface tension (mN/m) Surface age (msec) water Du-Wett, 50 Actiwett, 60 Omniwett, 50 Nu-film 17, 60 ml/100 L Latron B, 60 Surface tension decay over time: adjuvants used in CPP

Surface tension (mN/m) Surface age (msec) water Du-Wett, 50 Actiwett, 60 Omniwett, 50 Nu-film 17, 60 ml/100 L Latron B, 60 Surface tension decay over time of adjuvant solutions used in CPP Du-Wett, 100

Effect of plant surface wettability & droplet surface tension on the adhesion of 500 μm droplets 77% 5% 47%

Video of a spray droplet impacting a bean leafbean (fluorescent dye under UV light) = Cu spray (no adj) on upper surface of a kiwifruit leaf (CA of both leaves = 68°)

Video of a spray droplet impacting Chenopodium albumalbum = Cu spray (no adj) on lower surface of a kiwifruit leaf (CA of both leaves = 130°)

Video of a spray droplet containing super-spreader adjuvant impacting Chenopodium albumalbum = Cu spray + Du-Wett on lower surface of a kiwifruit leaf (CA of both leaves = 130°)

Wetting of hairy surfaces (Hort 16A fruitlet) Water sprayed to runoff (+Brilliant Blue dye) Du-Wett Spray 0.1% (+BB dye)

Recommendations for protectant sprays on spring canopies  Spray run-off volumes in early spring canopies are L/ha; around bloom no more than 1500 L/ha  2x concentrate sprays are recommended for protective chemicals; L/ha early on, no more than 750 L/ha late spring  Sprayer calibration is essential!  Adjuvant: Du-Wett at 400 ml/ha to ensure coverage of leaf surfaces  Dilute; use recommended chemical rate/ha ml/ha DW (e.g ml/100 L adjuvant)  2x concentrate: use recommended chemical rate/ha in half the dilute spray volume ml/ha DW (e.g ml/100 L adjuvant)  Use low volume sprays only if concentrated and with Du-Wett

 permit concentrate spray applications, saving time and $$  improve adhesion of large spray droplets & on hard-to-wet surfaces  ensure complete & even coverage of foliage with protectants in low- volume sprays  reduce drying time, reduce phyto, improve efficacy  used in fully dilute sprays only at very low concentrations  will cause loss of sprays to run-off with excessive spray volumes, dew (rain?)  potential to increase crop damage at high use rates and/or high water rates (penetration) Horticultural SUPER-SPREADER adjuvants…