IPM for thrips in greenhouse ornamentals:Building a foundation using biocontrol
Michael Brownbridge, Ph.D.
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
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
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
a
cbc
ab
bb
a
c
aa
b
cMea
n n
0. p
ests
per
po
t (4
pla
nts
)
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
Biocontrol for thrips in ornamentals:A basic program
SANITATIONEXCLUSION
© Ashley Summerfield, Vineland