1. Blinka, E., J. Bacheler, P. Roberts, J. Greene, M. Toews, D. Mott,
Evaluation of the relationship between stink bug pressure vs. yield under a regressive spray treatment.
Blinka, E., J. Bacheler, P. Roberts, J. Greene, M. Toews, D. Mott,
D. Robinson, J. Van Duyn
NCSU Clemson UGA

2. INTRODUCTION
Stink bugs can reduce yields and cotton quality (Barbour, et al. 1990, Bundy, et al. 1999, Greene and Herzog 2001, Willrich et al. 2003, Emfinger et al. 2004).
TAMU Extension

3. INTRODUCTION
Stink bug pest status continues to increase in cotton, infesting million acres and destroying 151,341 bales across the U.S. in 2006 (Williams 2007).
North Carolina: 51,607 bales lost.
South Carolina: 20,488 bales lost.
Georgia: ,000 bales lost.

4. INTRODUCTION
Bacheler et al. (2007) suggested that 3.5+ week old bolls or 1.25 inch diameter bolls are safe from stink bug feeding damage.
Bacheler et al. (2007) suggest that higher stink bug thresholds in cotton may be justified during both early and late periods of bloom.

5. OBJECTIVE
Evaluate the relationship between stink bug pressure vs. yield under a regressive spray treatment.

6. MATERIALS AND METHODS
Series of seven regressive spray treatment tests: two in NC in 2006 & 2007, two in GA in 2007, and one in SC in 2007. X X NC X X SC
X = 2007
X = 2006 GA X X X

7. MATERIALS AND METHODS 3 5 6 7 2 4 1
Figure 1. Number of applications per plot.
All plots were treated first week of bloom except Untreated Check plots (UTC).
Each week, another plot was removed from the spray schedule.

8. MATERIALS AND METHODS
Just prior to boll opening, 25 randomly selected bolls per plot (100/treatment) were assessed internally and deemed damaged if any internal warts, stained lint, or a combination of the two were found.
Middle two rows from all treatments at all locations were mechanically harvested and weighed to determine yields, except NC, Perquimans Co. in 2006 was hand harvested.

9. MATERIALS AND METHODS
Yield data were subjected to ANOVA and means were separated by LSD (p = 0.05)

10. RESULTS Location and Year % Damaged Bolls NC, Edgecombe Co. 2006 23%
Table 1. Percent Year End Boll Damage.
Location and Year
% Damaged Bolls
NC, Edgecombe Co. 2006
23%
NC, Perquimans Co. 2007
48%
NC, Wayne Co. 2007
32%

11. RESULTS a a a a a a a a

12. Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
RESULTS
(Yield Difference: Treated vs UT = lbs. lint/acre)
261.36
185.10
43.56
163.35
Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
-32.67
6-5
5-4
4-3
3-2
2-1
1-0
Week of Bloom

13. Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
RESULTS
(Yield Difference: Treated vs UT = 2.9 lbs. lint/acre)
44.7
36.6
29.9
Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
-10.8
-3.7
-49.1
-50.5
5-4
7-6
6-5
4-3
3-2
2-1
1-0
Week of Bloom

14. Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
RESULTS
(Yield Difference: Treated vs UT = 30.2 lbs. lint/acre)
113.03
72.60
9.88
Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
-31.94
-40.65
5-4
7-6
6-5
4-3
3-2
2-1
1-0
Week of Bloom

15. Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
RESULTS
(Yield Difference: Treated vs UT = lbs. lint/acre)
48.0
26.8
Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
-31.2
-44.3
-61.0
-70.4
-90.1
5-4
7-6
6-5
4-3
3-2
2-1
1-0
Week of Bloom

16. Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
RESULTS
(Yield Difference: Treated vs UT = lbs. lint/acre)
129.45
129.03
103.13
23.33
Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
-74.93
5-4
7-6
6-5
4-3
3-2
2-1
1-0
Week of Bloom

17. Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
RESULTS
(Yield Difference: Treated vs UT = lbs. lint/acre)
49.37
Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
-29.04
-27.59
-39.21
-55.17
-68.25
-78.41
5-4
7-6
6-5
4-3
3-2
2-1
1-0
Week of Bloom

18. Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
RESULTS
(Yield Difference: Treated vs UT = lbs. lint/acre)
145.31
93.77
Differences in Yield Based on Weekly Sprays (lbs. lint/acre)
47.92
-4.13
-43.79
-67.86
-86.89
5-4
7-6
6-5
4-3
3-2
2-1
1-0
Week of Bloom

19. RESULTS
Yield change from spray at designated weeks of bloom, NC & GA, under a progressive spray environment (n = 14 tests) Bacheler et al
62.6
Lb. Lint/Acre
17.1
15.3
-7.0
-9.2
-21.9
1-2
2-3
3-4
4-5
5-6
6-7
Week of Bloom

20. RESULTS
Yield change from spray at designated weeks of bloom, NC, SC, & GA, under a regressive spray environment (n = 7 tests).
31.48
19.62
17.83
-9.41
-4.38
-18.79
Lb. Lint/Acre
-86.56
7-6
6-5
5-4
4-3
3-2
2-1
1-0
Week of Bloom

21. RESULTS (Yield difference: treated vs. UT) (479) (762) (8) (-15) (106)
Relationship between stink bug damage to quarter-sized bolls and yield loss, 2005 – 2006 (Bacheler et al. 2007).
(Yield difference: treated vs. UT)
(479)
(762)
(8)
(-15)
(106)
Wayne, NC
2004 GA
2005
Union, NC
2005
Scot., NC
2006 SC
2006

22. CONCLUSIONS
2006 appeared to be a light stink bug year with 2007 being even lighter.
Yield data showed a numerical trend towards higher yields under 4 or more spray treatments.
High variation occurred between cotton lint gained or loss based on weekly spray treatments at all locations and years.

23. CONCLUSIONS
Reverse spray treatment data did not follow trends noted under a progressive spray treatment.
Light stink bug activity may explain some of the variation.
More Questions than Answers!

24. CONCLUSIONS
Is it possible that initial spray treatments reduced stink bug levels that were not able to rebound for remainder of experiment?
We need to gain more information concerning the impact of low stink bug levels on cotton.

25. “Identifying Practical Knowledge and Solutions
for Managing The Sucking-Bug Complex In Cotton: Research In The Southeast Region”
Southeast State Support Committees