Review Efficacy Residual Impact on yield

S. D. Stewart, K. L. Willis, B. A. Hanks, and S. J. Steckel(University of Tennessee)

G. M. Lorenz and C. K. Colwell (University of Arkansas)

Thrips Control in Seedling Cotton

Thrips Potential Injury

Leaf and terminal injury• Stunting• Delay in squaring

Plant or terminal death• Maturity delay• Crazy cotton• Stand and yield loss

Pest Complex Tobacco thrips

(Frankliniella fusca) Eastern flower thrips

(F. tritici) Western flower thrips

(F. occidentalis)

Untreated Treated

Thrips Biology Multiple generation per year

Overlapping generations are typical In seedling cotton, population often peak in late May or

early June Numerous alternate hosts are sources of infestations

Thrips (Thysanoptera: Thripidae): A multi-state survey: summary of observations for Arkansas, Alabama, Georgia, Louisiana, Mississippi, and Tennessee

Univ. California IPM Program

Thrips Management Preventative in-furrow insecticides or seed

treatments are routinely recommended Temik 15G (aldicarb, 0.53-0.75 lb ai/acre = 3.5-5 lb/a) Gaucho Grande (imidacloprid, 0.375 mg ai/seed) Cruiser (thiamethoxam, 0.30-0.34 mg ai/seed)

• Avicta Complete Pack (0.34 mg ai thiamethoxam/seed) In-furrow Orthene or acephate (0.90-0.97 lb ai/acre)

• Seed treatment of 8-25 oz/cwt

Supplemental foliar applications as needed Orthene (0.20-0.25 lb ai/a), Bidrin 8E (1.6-3 oz/a),

Dimethoate 4E (4-6 oz/a)

Thrips Trial: Planted May 8Stewart et al., University of Tennessee, 2006

0

5

10

15

20

Thrips/5 Plants (23 DAP)2500

3000

3500

4000

Seed Cotton (Lb/A)

NS (P = 0.44, LSD = 419 lb) (LSD, P <0.05) a

bcbcc c

bcbc

b

bcbc

UTC Temik(3.5 lb)

Temik(5.0 lb)

KC791230(3.5 lb)

KC791230(5.0 lb)

Temik (3.5 lb)+ G. Grande

Acephate 90(25 oz/cwt)

Cruiser(0.34 mg ai)

Couraze 2F IF(17.8 oz)

Gaucho Grande(0.375 mg ai)

Thrips Trial: Early Planted (April 17)Stewart et al., University of Tennessee, 2006

UTC Gaucho Grande(0.375 mg ai)

Gaucho 600 (9 oz/cwt)+ Experimental

Cruiser(0.34 mg ai)

0

5

10

15

20

25

30

Thrips/5 Plants (21 DAP)

a

b b b 2200

2300

2400

2500

2600

2700

2800

2900

Seed Cotton (Lb/A)

b

a

aa

(LSD, P < 0.05) (LSD, P < 0.05)

Thrips Trial: Early Planted (April 19)Stewart et al., University of Tennessee, 2005

UTC Cruiser(0.34 mg ai)

Gaucho 600(6.4 oz/cwt)

Gaucho Grande(0.375 mg ai)

Acephate 97(25 oz/cwt)

Acephate 97 (25 oz/cwt) +Acephate 97 (0.2 lb @ 1st leaf)

Acephate 97IF (1 lb)

Temik(3.5 lb)

KC791230(3.5 lb)

0

500

1000

1500

Lint (Lb/A)

(LSD, P < 0.05)

a

bbbbab

bbb

0

5

10

15

20

Thrips/5 Plants (24 DAP)

(LSD, P < 0.05)

a

b b b b b b bb

Thrips Trial: Planted May 5Lorenz et al., University of Arkansas, 2005

UTC Temik(5 lb)

Temik (5 lb) +Temik SD (5 lb)

Temik(3.5 lb)

KC791230(3.5 lb)

KC791230(5 lb)

KC791230 (5 lb) +KC791230 SD (5 lb)

Gaucho Grande(0.375 mg ai)

Cruiser (0.32 mg ai)

0

10

20

30

40

50

Mean Increase in Thrips from PreviousWeek (No./10 Plants), 15-22 DAP

0

200

400

600

800

1000

Lint (Lb/A)

NS (P > 0.10)

b48

b14 b

10

b18 b

20 b15

b19

a51

a36

(P < 0.01, LSD)

Stand Loss and DelayStewart et al., University of Tennessee

Planted April 17, 2006

(LSD, P < 0.05)

DPL444 - Gaucho

PHY370 - Gaucho

STN4554 - Gaucho

DPL444 - UTC

PHY370 - UTC

STN4554 - UTC

0

10

20

30

40

50

60

70

Num

bers

Plants/34 Ft(51 DAP)

Squares/M(67 DAP)

a aab

bbc

d

a a a

b bb

Delay and Yield LossStewart et al., University of Tennessee

Planted April 17, 2006

(LSD, P < 0.05)

DPL444 - Gaucho

PHY370 - Gaucho

STN4554 - Gaucho

DPL444 - UTC

PHY370 - UTC

STN4554 - UTC

0500

1000150020002500300035004000

Seed

Cot

ton

(Lb/

A)

1st Pick(Sep. 20)

2nd Pick(Oct. 3)

TotalHarvest

a a a b b c c c bc a a a aba ab

ddcbc

Significant variety by trt. interactions

At-planting and Foliar Thrips TrialLorenz et al., University of Arkansas

Planted May 17, 2006

0

50

100

150

200

250

300

Seas

onal

Tot

al N

o. T

hrip

s

3 Ratings (3, 7, 10 Days after Foliar Trt)

UTCTemik (5 lb)Cruiser (0.34 mg ai)Intruder (0.6 oz)Intruder (1 oz)Acephate (0.25 lb)Bidrin (4 oz)BAS320 (32 oz)Dimethoate (8 oz)Centric (1.5 oz)Carbine (1.1 oz)Karate 2.08 (1.5 oz)

a

cd

d d d

cd

b

cd

bc

dcdcd

(Student Newman Keuls, P < 0.10)

(22, 26 and 32 DAP)

Foliar Thrips TrialStewart et al., University of Tennessee, 2006

Selected treatments shown

UTC

Orthene 97 (0.25 lb)

Orthene 97 (0.125 lb)

Orthene 90 (0.25 lb)

Orthene 90 (0.125 lb)

V-10191 2SL (0.25 lb)

Dimethoate (6 oz)b bb b bb

(LSD, P < 0. 05)

b b b b b ba

0

10

20

30

40

50

60

Mea

n N

umbe

r of T

hrip

s

3DAT-A(5 Plants)

3DAT-B(4 Plants)

a

Chemical Leaf BurnStewart et al., University of Tennessee

Planted May 8, 2006

* All Treatments with 22 oz/a Roundup Weather Max (selected treatments shown)

UTC*

Orthene 97SP (0.25 lb)

Orthene 90S (0.25 lb)

V-10191 2SL (0.25 lb)

Dimethoate (6 oz)

Orthene 97SP (0.25 lb) +Dual Magnum (16 oz)

V-10191 2SL (0.25 lb) +Dual Magnum (16 oz)

c c

(LSD, P < 0.05)

0

2

4

6

8

10

12

14

% L

eaf B

urn

3 DAT

c c

bab

a

Concluding Remarks Thrips can cause stand loss, stunting, delay in

fruiting and harvest, and yield reduction Dramatic yield reductions more likely when unfavorable

weather occurs after planting Temik provides longer residual control (particularly

at rates above 3.5 lb/acre) However, the "standard" thrips treatments provided

similar yield protection in most environments Several foliar insecticides provide good control of

thrips populations (80-90%) Some have the potential to cause leaf burn, usually

“cosmetic” (i.e., dimethoate) Some are known to flare aphids and or spider mites (e.g.,

pyrethroids and acephate)