Almost Everything You Want to Know About Stink Bugs and What You Better Know about

Roundup Ready Cotton

Certified Crop Advisor Training

January 22, 2002

Macon, Georgia

Insecticide Applications per AcreGeorgia Cotton, 1986-2001

15.8

7.8

10.511.912.6

7.4

54.2 4.7 4.5

23.4 2.6

1.32.2 1.9

0

5

10

15

20

1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

No.

Ins

ecti

cide

App

lica

tion

s

Beltwide Cotton Conferences

Boll Weevil Era

--Active BWEP-- (does not include BWEP sprays)

--Boll Weevil Free-----------------------low populations

---------Bt Cotton--------

Survey MethodsInsect Boll Damage Survey: Georgia 2001

• Ten fields per county.– 5 Bollgard and 5 Non-Bt

– Fields had cutout

• Collected 100 bolls per field.– Approximately 50 bolls collected from

two locations.

– Sampled all harvestable bolls from

individual plants.

• Examined bolls for insect damage.– Worm Damage

– Bug Damage

• Insecticide application history.– Target Pest(s)

Counties Surveyed:

Appling, Brooks, Bulloch, Burke, Colquitt, Decatur, Dooly, and Terrell

Survey Methods• Green bolls examined

internally.

• Bolls with at least one lock with significant rot were considered damaged.

• Worm Damage

• Bug Damage

Percent “Bug” and Larval Damaged BollsInsect Boll Damage Survey: Georgia 2001

2.67 2.96

0

2

4

6

8

10

Worms Bugs

Per

cent

Dam

aged

Bol

ls

39 Bollgard and 43 Non-Bt Fields

Percent “Bug” Damaged BollsInsect Boll Damage Survey: Georgia 2001

3.21

2.7

0

1

2

3

4

5

Bollgard Non-Bt

Per

cent

Dam

aged

Bol

ls

• Complex of “Bugs” may feed on developing bolls.

** Prob |t| <0.0139 Bollgard and 43 Non-Bt Fields

Mean Insecticide ApplicationsInsect Boll Damage Survey: Georgia 2001

Bugs 1.16 0.31

Worms 0.24 2.48

Bollgard Non-Bt

1.22

2.52

** Prob |t| <0.0137 Bollgard and 42 Non-Bt Fields

**

Stinkbug “Complex”

• Predominant species include Southern Green Stink Bug and Brown Stink Bug

• Other true bugs such as Tarnished Plant Bug and Leaf Footed Bugs cause similar damage

• There are predaceous species such as the Spine Soldier Bug

Southern Green Stink Bug

Brown Stink Bug

Striped LeafFooted Bug

Bug Damage--What Does it Look Like?

• Fruit abortion

• Hawk-billed bolls

• External boll punctures

• Internal boll punctures, warts

• Internal rot

Misshapen or hawk-billed bolls result from poorpollination or poor seed development in one or more locks.

Bug feeding can result in external punctures. These sites serve as ameans of pathogen entry into thedeveloping boll. External sites donot always indicate internal entry or punctures.

Internal damage initially appearsas warty growth (within 24 hr).Discoloration and rot proceeds toa single seed, lock, or throughoutthe entire boll.

Stink Bug Threshhold

• Depend on reliable scouting procedures

• They are shy, mobile creatures

• What is damage?

• Adjacent crop has significant impact

• Best approach: Boll DAMAGE Count

Aren’t they shy!

Cotton / Peanut Interface

When should we spray?

0

200

400

600

800

1000

1200

10% 20% 30% 1bug/6 ft Unt

Threshold Level

lb L

int p

er A

cre

ab a abc bc c+109+93 +66 +32

4.2Bidrin

2.0Bidrin

0.6Bidrin

1.0Bidrin

0appl

$48.48*$20.90* $34.61* $10.89*

*Net= $0.60/lb - $8.31/appl

J. Greene, summary of 5 locations

“Bug” Threshold

• When 20% of medium sized bolls (the diameter of a quarter) display internal signs of feeding and stink bugs are observed. OR

• Treat when stink bugs number 1 per 6 row feet.

Stink Bug Control

Stink Bug Trial 2000Irwin County GA - Tyler

Stink Bug Trial 2000Irwin County GA - Tyler

19

40

71

54

199 8

20

0

20

40

60

80

100

26-Jul 2-Aug 9-Aug 16-Aug

Per

cent

Dam

age

Untreated Karate

744866

0

250

500

750

1000

Untreated Karate

Lin

t (l

bs

per

acr

e)

Treated July 27

Stink Bug Field TrialLang Rigdon Farm - 2001

0

2

4

6

8

10

12

14

16

Untreated Decis 2 ozs Bidrin 8 ozs

Bug

s pe

r 18

Row

Fee

t

SG Adults Brown Adults Brown Nymphs OtherLSD (p=0.05) 4.4Treated Sept 2

14.33

3.33

0.67

2 row cotton plots in peanuts.

4 DAT

Southern Green vs. BrownInsecticide Susceptiblity

Pyrethroids Bidrinmethyl parathionVydate

OP’sBidrinmethyl parathionOrthene

Pyrethroids are weak on Brown Stink Bug

When does a bollreach the point thatit will not sufferdamage from bugs?

About 25 days

Top 12 Varieties and Technology in 2001 GA Crop

B/RR RR B Conv DP 458 BR ST 4892 BR DP 451 BR DP 655 BR

DP 5415 RR DP 5690 RR SG 521 RR DP 436 RR DP 425 RR

NuCOTN 35B

DP 5415 FM 989

Distribution across technology (% of total acreage)

41.5 40.8 4.6 12.1

(USDA Ag Marketing Survey, August 2001)

Top 12 Varieties in 2001 GA Crop

B/RR RR B Conv DP 458 BRR (20.6) ST 4892 BR (5.2) DP 451 BRR (4.8) DP 655 BRR (2.5)

DP 5415 RR (16.5) DP 5690 RR (15.0) SG 521 RR (3.4) DP 436 RR (3.2) DP 425 RR (2.7)

NuCOTN 35B (2.0)

DP 5415 (2.3) FM 989 (2.0)

USDA Ag Marketing Survey, Aug 2001

Technology Distribution (%) of 2000 vs 2001 GA Crop

0

10

20

30

40

50

(%)

B/RR RR B Conv

2000 2001

Roundup Ready Cotton Issues

• Variety performance

• Mechanism of crop “tolerance”

• Weed management programs

• TIMING of applications

RR Cotton Variety Performance

• Glyphosate (properly applied) does not affect the yield of RR cultivars

• In terms of yield potential, RR cultivars are not superior

• Conventional, Bollgard/RR, and Bollgard varieties outperform RR varieties

In variety trials in high yield environments, RR varieties are rarely in the top 20 percent.

RR Cotton Mechanism of Crop Tolerance

• A genetically altered enzyme system provides tolerance to glyphosate in the production of shikimic acid (amino acids)

• Glyphosate is not degraded within the plant

• Excellent vegetative tolerance but marginal tolerance in developing flower

• Can sterilize pollen

Roundup Ready Weed Management...

there are many, many options.

Roundup Ready Programs

Options (6) Preferred StandardPPI / PRE Dinitroaniline

OTT 1-2 LF

OTT 2-4 LF

glyphosate orglyphosate + Staple

PDIR 6-10 LF

LAYBY

diuron or prometryn +MSMA

RR Cotton Weed Management--Reasons to Include

Conventional Herbicides in Program

• Reduce potential for early competition

• Improve control spectrum

• Reduce selection pressure for weed shifts and resistance

• Avoid phantom fruit loss with (mis) directed applications

Not Precise Enough!

Timing is Everything!

4-Leaf Cotton

5-Leaf Cotton

Too Late?

Not Precise Enough!

Precision is critical with directed applicationsof glyphosate in RR cotton!