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

1. Vector of Tomato Spotted Wilt Virus (TSWV)

2. Current infestation areas of thrips & TSWV

3. IPM• Correct identification required for correct response• Economic thresholds with and without TSWV• Control measures• Resistance management• Preventative practices

IPM of Western Flower Thripsmy discussion points

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

• Historically only Florida flower thrips

• Recently small pockets of Western flower thrips

• Homestead & adjacent areas with Thrips palmi

• 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

2006 - Present

1985 - 2005

F. tritici

F. occidentalisF. fusca

F. bispinosa

Thrips palmi

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

05

1015202530354045

UTC Spintor 2SC6 fl oz/A

Baythroid2E 2.8 fl

oz/A

Radiant 6 fl oz/A

3 DAT7 DAT8 DAT

Dr. Tom Kuhar – VA Eastern Shore

WFT Adults & Minute Pirate Bugs (MPB) Collected from Pepper Blooms

Ft. Pierce, FL, Spring 2007May Untreated

checkPyrethroid Intrepid

WFT MPB WFT MPB WFT MPB8 48 5 94 4 83 4

10 82 8 136 0 78 1014 54 12 148 2 30 1116 64 10 245 0 144 621 86 8 147 1 60 323 50 4 251 0 77 529 79 3 182 1 34 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

Thrips and Orius density on pepper flowers

05

10152025303540

Dates

Thrip

s/pe

pper

flow

er

0

0.05

0.1

0.15

0.2

0.25

Oriu

s/p

eppe

r flo

wer

Thrips - SunflowerThrips - No SunflowerOrius - SunflowerOrius - No Sunflower

Impact of insecticides on prey:predator ratios in peppers

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

Average MPB per sample

Ave

rage

thrip

s pe

r sam

ple

Gamma-cyhalothrin Treatments

Permethrin Treatments

Untreated Check

Methoxyfenozide Treatment

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