1. J. H. Temple, P. L. Bommireddy, P.Marcon, S. Micinski, & B. R. Leonard
Rynaxypyr™ (DPX-E2Y45) & Cypermethrin: Susceptibility of a Selected Lepidopteran Cotton Pest
J. H. Temple, P. L. Bommireddy,
P.Marcon, S. Micinski, & B. R. Leonard

2. Bollworm Sampling Sites
Collection sites ( )

3. Trends in Midwest: Pyrethroid Efficacy in CEW Declines: % Larval Control in Sweet Corn (Capture/Warrior; WI, MN)
Year
Mean
1997 93
1998 88
1999 81
2000 49
2001 17
2002 41
2003 40
2004 69
2005
2006
2007 61 35
Looks like the % larval control is going down over time. From later slides, mostly adults are being tested for resistance to pyrethroids. I thought there was not necessarily a link between adult resistance and larval resistance, is that not accurate? Not always a good link; That is why I also included slides for Direct Larval Assays (cypermethrin and Warrior, which are showing resistance too). (as per slide 9)
Hutchison et al.
Univ. of Minn.

4. Objective Evaluate Bollworm Susceptibility to: 1. Cypermethrin
2. Rynaxypyr (DPX-E2Y45)

5. Adult Vial Test
5 & 10 μg/vial
Cypermethrin

6. Collection Sites Across LA
Cotton Acreage
Sampling Sites

7. Historical Bollworm Survival (AVT)
May-Sept 1988 to 2006
May-Sep 2007*
Cypermethrin 5 µg/vial
% Survival
Louisiana
* 8 collection sites, 1000 moths tested

8. Annual Bollworm Survival (5 µg/vial)
Cypermethrin
Percent Survival

9. Annual Bollworm Survival (10 µg/vial)
Cypermethrin
Percent Survival 0%

10. Average Bollworm Survival (AVT) 2005-2007
Late Season Field Collections
Cypermethrin 5 µg/vial
Percent Survival

11. TOPICAL APPLICATION

12. Louisiana Bollworm Topical Results
Colony N
LC501
95%CL
Slope RR
Winnsboro-04
160
6.12
2.92±0.37
7-22
Winnsboro-05
115
3.48
3.15±0.41
4-12
LSU Lab-06
240
0.20
2.56±0.36 NA
Winnsboro-06
220
3.50
2.69±0.34
Winnsboro-07
190
2.80
2.23±0.28
3-10
DuPont Lab-07
0.21
2.83±0.41
Resistance Ratios (RR) calculated from LD50 data (0.28 to 0.88 µg/g larval weight) derived
from Louisiana lab and field collections 1998 (Unpublished Data, J. Adamcyck and J. Gore LSU Dept. of
Entomology). 1µg/g larval weight.

13. Summary Pyrethroid Monitoring
LA BW susceptibility to pyrethroids continues to decline.
Widespread concerns (Midwest, TX, Southeast)
Continue monitoring program during 2008.
Alternative control strategies:
Transgenics and Alternative Insecticides (Rynaxypyr)

14. Coragen™ SC & Altacor™ WG
Rynaxypyr™ (DPX-E2Y45)
Coragen™ SC & Altacor™ WG
Novel insecticide chemistry
Class: Anthranilic diamides
MOA: Muscle Functions
Calcium Channels
High toxicity to Lepidoptera at very low rates, long residual
Feeding cessation, lethargy, paralysis,
and death

15. Bollworm Colonies Rynaxypyr LSU Lab DuPont Lab Georgia Field
North Carolina Field
Virginia Field
Delaware Field
Louisiana Field

16. Diet Incorporation Methods
Formulated Rynaxypyr (35 WG) dissolved in distilled water to create stock solution 100 µg/ml
Nine serial dilutions created µg/ml diet
3rd instar larvae placed on range of treated diet doses
Mortality rated at 24, 48, 72, 96 HAE
Mortality analyzed using Polo-Plus Probit Analysis to create LC 50’s

17. Diet Incorporation of Rynaxypyr
LSU Lab Bollworm
Percent Mortality
0.069
LC50 Range ( )
Dose (µg/ml of diet)

18. Bollworm Diet Incorporation Results
Colony N
LC501
95%CL
Slope Χ2
LSU Lab
280
0.07
2.85±0.31
11.82
Georgia
240
0.04
3.15±0.41
1.80
North Carolina
180
0.05
2.56±0.36
3.43
Virginia
2.69±0.34
2.90
Delaware
210
0.09
2.23±0.28
4.27
Louisiana
0.06
2.83±0.41
3.12
DuPont Lab
2.78±0.35
2.69
1µg/ml diet

19. Lab and Field Bollworm Survival (AVT)
Cypermethrin 5 µg/vial
Percent Survival 0%

20. Lab and Field Bollworm Survival (Diet)
Cypermethrin 5 µg/vial
Percent Survival
LC50 values to Rynaxypyr (Diet incorporation)
0.069
0.061 0%

21. Rynaxypyr Summary Toxic at relatively low doses
Activity: Contact and Ingestion
All Bollworm colonies had similar LC50’s (5-states,
2-Lab colonies)
No Cross-resistance to pyrethroids observed

22. Acknowledgments
Sandy Stewart, Brandi Woolam, Karla Emfinger, Trey Price,
Sierra Jones, Sara Lowe, Nick Cannady, Josh Russell,
and numerous other student workers at the Macon Ridge
Research Station.
Bollworm collections: Kathleen Heldreth, Glenn Hammes,
Tom Kuhar, John Van Duyn, Bob Williams, Chris Williams,
Joe Saienni, and Greg Hannig.