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Management of vegetable pests in the Salinas Valley
Shimat Joseph University of California
Salinas, CA
Pests covered
Springtails – Lettuce
Cabbage maggot – Brassicas
Bagrada bug - Brassicas
Overview
Subterranean springtail - Protaphorura fimata
Cabbage maggot – Delia radicum
Bagrada bug – Bagrada hilaris
Questions
1. What is causing the inconsistent lettuce stand?
Monitoring
Garden symphylans?
Method - Experiment design
80 inch
12 beds
Untreated check Insecticide treatment
Application 1 (2-3 days before planting) Warrior II (Lamda-Cyhalothrin) : 1.6 fl oz Mustang (Zeta-Cypermethrin): 4.0 fl oz Widespread max: 2.0 fl oz
Application 2 (at planting) Warrior II (Lamda-Cyhalothrin) : 1.6 fl oz Widespread max: 2.0 fl oz
Application 3 (20 days after planting) Warrior II (Lamda-Cyhalothrin) : 1.6 fl oz Mustang (Zeta-Cypermethrin): 4.0 fl oz Widespread max: 2.0 fl oz
Untreated check Insecticide treatment
Results
Untreated check
Insecticide treatment
Results
Untreated check Insecticide treatment
Results
Untreated check Insecticide treatment
Results
Springtail: [Protaphorura fimata (Family:
Onychiuridae)]
Results: Springtail counts
0
50
100
150
200
250
300
350
7 March 15 March 22 March 28 March
Untreated check
Insecticide
a a
b
a
a
a
a a
9 March: First treatment
11 March: Second treatment
30 March: Third treatment
No. of springtails per trap
Results: Fresh weight
0
5
10
15
20
25
30
35
4 April
0
200
400
600
800
1000
1200
22 April0
5
10
15
20
25
30 May
Untreated check
Insecticide
Fresh weight (g/Kg) of lettuce per 61.3 square meter
g g Kg
a
b
a
a
a
b
(Pre-thinning) (Post-thinning) (Near harvest)
Questions
1. What is causing the inconsistent lettuce stand?
2. Would springtails really feed on geminating seeds/plants?
Germination of leafy lettuce
Without springtail With springtail
Seed predation
0
2
4
6
8
10
12
14
16
18
0 20 50 100
Number of seeds injured
Springtail in soil bioassay
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
No springtail Springtail
Fresh weight (g)
0
0.005
0.01
0.015
0.02
0.025
0.03
No springtail Springtail
Dry weight (g)
Leaves
Stem
Crown
Root
Site of feeding
0
0.5
1
1.5
2
2.5
Leaves Stem Crown Root
a
b
b
c
Questions
1. What is causing the inconsistent lettuce stand?
2. Would springtails feed on geminating seeds/plants?
3. How to monitor springtail in lettuce and what are the best traps?
4. How long we should deploy the traps in the field?
Trap comparison
Beet Potato Berlese funnel
Trap comparison 1
0
5
10
15
20
25
30
Beet Potato Berlese funnel
Crop: Romaine lettuce Planting date: 1/2/2014 Date of deployment: 2/27/2014 a
b
b
Number of springtails captured
Trap comparison 2
0
0.5
1
1.5
2
2.5
3
3.5
Beet Potato Berlese funnel
a
b
b
Number of springtails captured
Trap comparison 3
0
20
40
60
80
100
120
Beet Potato Berlese funnel
a
b
b
Number of springtails captured
Trial 1: Beet trap age
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1 2 3 4 5
Crop: Romaine lettuce Planting date: 1/2/2014 Date of deployment: 3/4/2014
Days after deployment
a
a a
a
a
Number of springtails captured
Trial 2: Beet trap age
0
5
10
15
20
25
1 2 3 4 5
Days after deployment
Date of deployment: 3/11/2014
a
a a
a
a
Number of springtails captured
Summary
The white springtail (Protaphorura fimata) is a pest of lettuce
They feed on the germinating seeds of lettuce
Beet is the better bait than potato for monitoring this springtail
Do not leave the beet more than 3 days for monitoring
Cabbage maggot
Diptera (Anthomyiidae)
Delia radicum L. – cabbage maggot
Delia antiqua (Meigen) – onion maggot
Delia platura (Meigen) – seed corn maggot
Delia floralis (Fallen) – turnip maggot
Delia florilega (Zetterstedt) – bean seed maggot
Delia brunnescens (Zetterstedt) – carnation maggot
Delia echinata (Seguy) – carnation tip maggot
Cabbage maggot
Brooks 1951
Root maggot - Larvae
Cabbage maggot Onion maggot Seedcorn maggot
Life history
Feeds on roots of cool season vegetables
Root collar region
Root maggots feeding
New roots
25 January 2013
Research
• Stringent regulation with the use of organophosphate insecticides such as chlorpyrifos and diazinon
• OPs are usually applied “at planting along with seeds”
• With alternate insecticide being used - Timing the insecticide application is critical to protect initial phase of plant development
• In Salinas – broccoli is mostly seeded
Exclusion cage study
Method: example
Treatment 1st 14-d 2nd 14-d 3rd 14-d
Always exposed
Exposed in 1st 14-d
Exposed in 2nd 14-d
Exposed in 3rd 14-d
Never exposed
CRB design with 50 reps
At emergence
Results: summer Seeds planted: May 14 Traps set: May 23
0
20
40
60
80
100
0 1-14 15-28 29-42 43-56 57-70 1-70
Exposure periods (Days after emergence)
% cabbage maggot injured plants
Incidence of CM eggs
0
20
40
60
80
100
1 2 3 4 5 6 7 8 9 10 11
Border
Center
Mean No. eggs per 15 plants per zone
Week after planting seeds
Crop: Broccoli Sites (Reps): 3
*
Adults
0
100
200
300
400
500
600
1 2 3 4 5 6 7 8 9 10 11 12
Border
Center
Mean number of flies per trap per zone
Week after planting seeds
Insecticide application timing - turnip
Insecticide: Chlorpyrifos
0
0.5
1
1.5
2
2.5
3
3.5
4
At Planting 3WAP
0
0.5
1
1.5
2
2.5
3
At Planting 3WAP
0
0.2
0.4
0.6
0.8
1
At Planting 3WAP
Severity of cabbage maggot infestation
Summary
For seeded-broccoli: First peak of cabbage maggot egg laying occurred three week after plant emergence
Cabbage maggot adults were present throughout the growing period
Insecticide application at three week after plant emergence looked better on cabbage maggot suppression
For transplanted-broccoli: cabbage maggot infestation was observed at second week after planting
Cross-vane trap
Look for info at:
Blog: Salinas Valley Agriculture
Facebook: UCCE Monterey
Acknowledgement
Pest control advisors and growers
Christian Ramirez, Jesus Martinez, Chris Bettiga, Jorge Zarate
Funding: CA Leafy greens Research Program and UC IPM
