IPM for thrips in greenhouse ornamentals:Building a foundation using biocontrol

Michael Brownbridge, Ph.D.

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Western flower thrips: why are they so hard to control?

Adult to adult 20-30 days

• Resistant

• Which species do you have?

Development of thrips in 60 days at 20° C

What species do you have?

Western flower thrips or onion thrips? Both now common in ornamentals

Onion thrips Western flower thrips

Summerfield, A. and Jandricic, S. 2018. Simple key to important thrips pests of Canadian greenhouses. GreenhouseIPM.org/pests/thripskey

Biocontrol-based IPM

• NOT the same as a pesticide program (reactive)

• Preventative, long-term approach

‒ Applications/releases made before pests observed

‒ Repeated as-needed

• Pest ID essential, environmental conditions suit the BCA

• Where possible, production methods should support biocontrol

Components of a thrips biocontrol program

• Prevention

• Natural enemies (predators)

‒ Foliar, e.g. N. cucumeris, A. swirskii, A. limonicus, Orius

‒ Soil, e.g. S. scimitus, G. aculeifer, G. gillespiei, Dalotia (Atheta)

• Biopesticides

‒ Foliar, e.g. BotaniGard, BioCeres, Velifer, Met52

‒ Soil, e.g. nematodes (S. feltiae), Met52

• Cultural

Biocontrol in production: A case study in chrysanthemums

Integrated use of biocontrol agents from propagation thru’ finishing to shipping

Prevention – before and during production

Sanitation

• Clean up crop residues

• No pet plants

• Disinfect benches, flood tables, drip lines, etc.

• Minimize weeds outside the greenhouse (?)

Exclusion

• Keep out intruders

• Screen vents

• Know where hot spots occur

Misting and blackout stages

• BotaniGard® or Met52 EC

‒ Weekly sprays (3x)

• Nematodes (S. feltiae)

‒ Drench, weekly

• Predatory mites

‒ N. cucumeris

‒ Broadcast weekly (3x)

Mini Airbug

ProductionPots at final spacing, canopy not touching

• Predatory mites

‒ cucumeris mini sachets

‒ one per pot

• Nematodes (S. feltiae)

‒ Weekly until canopy closes

• Biopesticide sprays

‒ BotaniGard, BioCeres

FinishingCanopy touching

• Many switch to swirskii mini-sachets

• Possible to reduce sachets to one per 2-3 pots

There are many possible variations on this basic program

Use in other cropse.g. Petunia

Spring bedding plants

• Not economical to use one sachet/pot

• Two to four sachets per shuttle tray

Foliar predators (mites)How they work

Which predatory mite to use?

Neoseiulus cucumeris

The “old standby”

Amblyseius swirskii

The “enigma”The “rock star”

Amblydromalus limonicus

2-3x 2-3xCost:

Soil-dwelling predators

• Predatory mites, rove beetles (Dalotia)

• Apply once for a short-term crop; distribute manually soon

after planting, or on the planting line

Microbial biopesticides

• BotaniGard, BioCeres, Velifer, Met52EC – foliar sprays

Met52 plus N. cucumeris

0

100

200

300

400

500

600

700

800

4wks 8wks 4wks 8wks

Thrips Spider mite

control Success

Met52 EC Met/ cucu

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ests

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Vineland data; not to be reproduced without permission

Microbial biopesticides:Application equipment and method is critical to success

Cold foggers:Dramm AutoFog™

Hydraulic sprayers

Cultural practices: mass trappingSystem supports biocontrol

PHOTOS COURTESY koppert canada

Easiest way to take pests out of circulation

Which colour is best?

Images courtesy Dr. Sarah Jandricic, OMAFRA

Biocontrol for thrips in ornamentals:A basic program

SANITATIONEXCLUSION

© Ashley Summerfield, Vineland

michael.brownbridge@gmail.com