A Nursery Triptych Three studies in spraying

Dr. Jason Deveau ● OMAFRA Application Technology Specialist ● Winter 2015

The Garden of Earthly Delights - Hieronymus Bosch, c. 1500

Backpack vs.

Mistblower

Horticultural Crops Ontario, the grower co-operators, Vaughn Agricultural Research Services Inc., Ms. Kathryn Hoshkiw and Ms. Carly Decker are

gratefully acknowledged for making this research possible.

• Is there a significant difference in how spray is deposited when the same volume-per-hectare is applied using an air blast sprayer versus a hand boom versus a mist blower?

The question

• Air blast applications were compared to hand boom in mature highbush blueberry, apple and grape plants using water-sensitive paper (2012)

• Air blast applications were compared to mist blower in peach, raspberry and grape plants using water-sensitive paper (2013)

• If drift isn’t a concern, the mist blower resulted in the most consistent coverage, with a higher droplet density and par surface coverage compared to air blast

• Handboom coverage was typically poor

Typical Airblast Coverage

Typical Mist Blower Coverage

Thanks to Kristy Grigg-McGuffin (OMAFRA Pome Fruit IPM Specialist), summer students Taylor Wallace, Carly Decker, Megan Leedham, and Tara

Wiedeman, statistical expertise by Behrouz Ehsani, and the grower co-operators for making this research possible.

Crop-Adapted

Spraying

• Most pesticide label rates reflect the area of the planting (e.g. L/ha), not the area-density of the plant canopy

• A fixed, prescribed spray volume and/or rate is insufficient to match plant canopy variability

• An hectare of corn is a hectare of corn, but a hectare of whips or shrubs…

• An hectare of corn is a hectare of corn, but a hectare of whips or shrubs…

Possible impacts

Over Spraying Under Spraying

> Money in chemicals/time < Efficacy

> Unnecessary contamination > Pest resistance over time

> Spraying to compensate

• The CAS model adjusts the amount of pesticide per unit ground area to achieve consistent foliar coverage for canopies of varying shape and density

• When achieved with sufficient accuracy, pesticide efficacy is maintained

How does it work?

The method

• In Ontario, I’m testing this in apple orchards, but Dr. Heping Zhu is doing it in nurseries using his Intelligent Sprayer

• First, the operator has to calibrate the sprayer – preferably for each significantly different crop…

The goal is to achieve a minimum of

85 medium sized droplets per cm2 and a total area of 10-15% coverage for most foliar

insecticides / fungicides

2011 - Preliminary Trials

• Based on CAS, an Ontario apple orchard applied ~35% less Mancozeb© than label rate for one season (no control)

Saved $4,140.00 that year just for

one fungicide

Surplus Pesticide

Harvest Quality Harvest Quality

2011 - Powdery mildew in roses

• Similarly, in 2011 we controlled PM in roses using optimized rates

2012 – RIP Ontario apple blossoms

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2013 and 2014 - Full Trials

• Sprayer operators used the optimized settings and rates for the CAS (treatment) block, and their typical methods for the control blocks

• Students scouted each week for 13-15 weeks and apples were collected at harvest

Orchard saved 39% compared to control blocks

• Sometimes pest / damage counts were significantly higher for CAS and sometimes for control

• However, when the actual counts over the season were graphed, they never came anywhere near spray or economic threshold

Results

Two Spotted Spider Mite (2013)

• Leaves sampled and nymphs and adults counted under microscope

Two Spotted Spider Mite (2014)

• Leaves sampled and nymphs and adults counted under microscope

• CAS worked in both high density and semi-dwarf orchards – Heping showed this method can work in nurseries

Conclusions

• Orchardists reported that these methods were intuitive and that they would be willing to expand their use of use CAS

• Use water-sensitive paper and calibrate based on coverage

Horticultural Crops Ontario, Ground Covers Unlimited, Pentair (Hypro) and Nemapro are gratefully acknowledged for making this research possible

Nematode

Re-suspension

• Responded to grower claim that nematode applications were becoming less effective

• Determined that the concentration of nematodes was dropping significantly over the course of the spray application

The problem

Grower identity cleverly protected Grower identity cleverly protected

Pump

Strainer

Pressure

Gauge

Tank

Bypass

Boom and

Nozzle(s)

Agitator

Tip Strainers

• There’s only so many places they could be going…

• Maybe they’re stranded on the poly tank walls like soap scum… If so, can we rinse them off?

• Collected samples over the course of spraying and counted nematodes per ml

@ spray_guy Jason Deveau

THANK YOU QUESTIONS?