Transcript Western Flower Thrips - University of Florida

Control of Western Flower Thrips
Through
Integrated Pest Management in
Tomato and Pepper
Presented by: Dr. Charles Mellinger,
Glades Crop Care, Inc.
August 29, 2008
IPM of Western Flower Thrips
my discussion points
1. Vector of Tomato Spotted Wilt Virus (TSWV)
2. Current infestation areas of thrips & TSWV
3. IPM
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Correct identification required for correct response
Economic thresholds with and without TSWV
Control measures
Resistance management
Preventative practices
2. Current Situation - Thrips & TSWV
• TSWV reservoirs—inadequate knowledge
• Positive TSWV Identification in:
– Tampa area peppers & ornamentals
– Homestead tomatoes
– Emilia
– Georgia Transplants
• Summary – very little at this point
compared to Southeastern U.S.
TSWV Symptoms
Emilia with TSWV Symptoms
2. Current Situation - Thrips in South Florida
1985 - 2005
• Historically only Florida flower thrips
• Recently small pockets of Western flower thrips
• Homestead & adjacent areas with Thrips palmi
2006 - Present
• Populations changing and moving
• New large populations of WFT-east coast
• Significant population of other important thrips
• Summary – thrips are becoming very important
in South Florida crops
Thrips palmi
F. occidentalis
F. fusca
F. tritici
F. bispinosa
3. IPM
• Correct identification of thrips’ genus/species
required for correct response
• Economic thresholds are different
• Chemical control choices are different
• No pyrethroids
• Rotation and resistance management are
different
Insecticide Treatment for WFT
Larvae Control in Spring Tomatoes
Number of Thrips Larvae per 10 Leaves
45
40
35
30
25
20
15
10
5
0
3 DAT
7 DAT
8 DAT
UTC
Spintor 2SC
6 fl oz/A
Dr. Tom Kuhar – VA Eastern Shore
Baythroid
2E 2.8 fl
oz/A
Radiant
6 fl oz/A
WFT Adults & Minute Pirate Bugs
(MPB) Collected from Pepper Blooms
May
Ft. Pierce, FL, Spring 2007
Untreated
Pyrethroid
Intrepid
check
8
10
14
16
21
23
29
WFT
48
82
54
64
86
50
79
MPB
5
8
12
10
8
4
3
WFT
94
136
148
245
147
251
182
MPB
4
0
2
0
1
0
1
WFT
83
78
30
144
60
77
34
MPB
4
10
11
6
3
5
12
3. IPM-Preventive Practices
• Monitoring
– Pre-planting: weeds and surrounding fallow
– During crop production
– During crop and post crop destruct - Impact on
adjacent crops and fields
• Varietal resistance—few varieties in pepper to
TSWV
• Reflective mulch---reduced #’s and incidence
• Adjacent grower notifications
• Conservation of the Thrips predator—The
Minute Pirate Bug—Orius insidiosus
Minute Pirate Bug (MPB)
Orius insidiosus
Larva
Adult
Sunflowers
in pepper for
thrips control:
more Orius,
fewer thrips
Orius density in field without sunflower
Gray: <0.01-0.05
Green: 0.05-0.1
Blue: 0.1-0.5 Red: >0.5
Orius per pepper flower
Orius density in field with sunflower
Gray: 0.01-0.05 Green: 0.05-0.1
Blue: 0.1-0.5 Red: >0.5
Orius per pepper flower
Thrips density in field without sunflower
Gray: <1-5 Green: 5-15
Blue: 15-30 Red: >30
Thrips per flower
Thrips density in field with sunflower
Gray: <1-5
Green: 5-15
Blue: 15-30 Red: >30
Thrips per flower
0.25
0.2
Orius /pepper flower
40
35
30
25
20
15
10
5
0
Thrips - Sunflower
Thrips - No Sunflower
Orius - Sunflower
Orius - No Sunflower
0.15
0.1
0.05
0
8Ja
23 n
-Ja
n
6Fe
20 b
-F
eb
1Ma
15 r
-M
ar
1Ap
10 r
-A
16 pr
Ap
24 rl
-A
pr
1Ma
y
Thrips/pepper flower
Thrips and Orius density on pepper flowers
Dates
Impact of insecticides on prey:predator
ratios in peppers
Average thrips per sample
700.0
Gamma-cyhalothrin Treatments
600.0
500.0
Permethrin Treatments
400.0
Methoxyfenozide Treatment
300.0
200.0
Untreated Check
100.0
0.0
0.0
1.0
2.0
3.0
4.0
5.0
Average MPB per sample
6.0
7.0
8.0
Summary
• WFT expanding in South Florida
• WFT excellent vector of TSWV
• Augment pepper crop with sunflower
• Few WFT Pesticide controls
• Must ID thrips population for correct
response
• Must scout for correct response