1. 2017 Corn and Sorghum Insect Update
Dominic Reisig NCSU Entomology and Plant Pathology

2. Sugarcane aphid distribution 2016

3. Potential yield loss if not managed
Grain producers
Pre-boot %
Boot %
Heading 67%
Soft dough 21%
Sweet sorghum producers
Brix can drop to unusable level in several days
Can reduce syrup amount recovered
Renders a bitter taste and off flavors to syrup

4. Simple threshold Pre-boot through boot Heading through dough stage
20% plants infested with localized areas of heavy honeydew and established colonies
Heading through dough stage
30% plants infested with localized areas of heavy honeydew and established colonies
Preharvest
Aphids on the flag leaf or grain head causing harvest problems with honeydew

5. Best insecticide for sugarcane aphidab ab a ab
abcd
abc
abcde ab
abc ab
abc
abc bc cd de ab b b e b bc c

6. entomology.ces.ncsu.edu

7. Current issues in corn Over-reliance on insecticidal seed treatments
Timely planting
Weed management
Rotate away from corn
Use starter fertilizer
Ensure proper drainage
Stink bugs
Corn earworm

8. Corn Insecticide Seed Treatments
Can I boost a seed treatment with an in-furrow?
Any new products out there?
What can we do if we lose insecticide seed treatments?

9. Wireworm – North Carolina – Corn
Conoderus lividus
Conoderus lividus
Conoderus vespertinus
Conoderus vespertinus
Melanotus communis
Melanotus communis
Glyphonyx spp.
Glyphonyx spp.

10. Wireworm – North Carolina – Corn 0 = No Control, 2 = Poor Control, 4 = Marginal Control, 6 = Fair Control, 8 = Good Control, 9 = Excellent Control
N = 4
N = 4
N = 1
N = 3
N = 4
N = 4
N = 4
N = 2
N = 2
N = 2
N = 1
Mean Rating

11. Untreated
Capture LFR 6.4oz
Counter 10lb
Poncho Counter 10lb
Poncho 500
Poncho Counter 10lb
Poncho 1250

12. Lumivia chlorantraniliprole
Labeled use rate from 0.25 to 0.75 mg per seed (250 to 750)
Offering on newer DuPont/Pioneer hybrids
Cruiser Lumivia 250
Anticipate no problems with maximum labeled season rate for chlorantraniliprole
Highest use rate of Lumivia still leaves room for nearly two sprays of Prevathon at 14 oz
“Do not apply other seed treatment products to seed already treated with Lumivia”

13. Summary of Five Greenhouse Trials
Treatment
Rate ug AI/seed
Mean ± SE
% damaged seeds
% wireworm mortality
% healthy corn seedlings
Lumivia™ 625FS + Cruiser 5FS
250 +
250
1.5 ± 0.6
50.5 ± 9.0
81.5 ± 10.9
Poncho Votivo
1,250
2.0 ± 0.9
62.5 ± 11.0
87.0 ± 8.1
Poncho 600FS
500
1.0 ± 0.6
58.0 ± 9.6
77.5 ± 5.8
Cruiser 5FS
2.5 ± 1.1
50.0 ± 9.7
87.0 ± 4.5
Untreated Check -
27.5 ± 9.0
6.5 ± 3.2
68.0 ± 10.1
Tom Kuhar, VA Tech

14. Virginia Beach- Moderate Wireworm Pressure
Treatment
Stand count/
25 row ft
26 DAP
% stunted plants
Mean plant height (cm)
43 DAP
Grain Yield
(lbs/25 row ft)
Lumivia™ 625FS + Cruiser 5FS
250 +
250
30.0
3.3 b
35.8 ab
Poncho Votivo
1,250
25.0
1.7 b
37.6 ab
Poncho 600FS
500
0.0 b
39.5 a
Cruiser 5FS
4.2 b
33.9 ab
Untreated Check -
29.8
50.4 a
29.7 b
Tom Kuhar, VA Tech

15. White Grub – North Carolina – Corn 0 = No Control, 2 = Poor Control, 4 = Marginal Control, 6 = Fair Control, 8 = Good Control, 9 = Excellent Control
N = 6
N = 3
N = 1
N = 1
N = 2
N = 2
N = 2
N = 1
N = 4
N = 1
N = 4
Mean Rating

16. Untreated
Capture LFR 6.4oz
Counter 10lb
Poncho 500
Poncho Counter 10lb
Poncho 1250
Poncho Counter 10lb

17. Effectiveness of Lumivia for White Grubsab ab ab ab
abc ab ab
abc b
abc bc c

18. Lumivia
Untreated
Poncho 1250

19. Seed Treatments vs. In-Furrow for White GrubsAB AB
ABC
ABC
ABC BC BC C

20. Lumivia- Hyde Co. 2014 a ab
abc
abc bc bc c c c

21. 2014
2015

22. Untreated
Poncho 1250
Cruiser 250 +
Lumivia 250

23. Cruiser Lumivia
Poncho 1250
Untreated

24. Untreated
Poncho/VOTiVO
Cruiser Lumivia
Poncho 1250

25. One trial
Two trials
Four trials
Four trials

28. bifenthrin at 6.4 oz/A =
0.025 lbs/A
zeta-cypermethrin at 4.0 oz/A=
bifenthrin LC50= 0.1 µg/ml
zeta-cypermethrin LC50> 1 µg/ml

29. Stink Bug Thresholds Georgia thresholds
Prior to VT - 25% infested plants
R1 - 50% infested plants
R % infested plants
Spray ~7 days after adjacent wheat harvest

30. Distribution of stink bugs on seedling corn (V4,V8 & V12)
Dotted horizontal line indicate the average height of the corn plant.
Each growth stage we searched 1200 plants. (4 field, from each field 100 plants from 5, 10, 15 m ie 300 plants/field * 4 = 1200). Random samples were taken, however plants which significantly lag behind the specific growth stage were replaced by an another random plant)
‘n’ = total number of stink bug/1200 plants.

31. Position of growing point in seedling corn in relation to soil level
Here is a box and whisker graph which shows the position of growing point inside the stem in relation to soil level. zero on y axis denote soil level and negative value indicate below soil level.
Notes:
All leaves and ear shoots that the plant will eventually produce are being initiated (formed) by V3, by V5 leaf and ear shoot initiation will complete and stem apex is just below or at ground level.
Early planting – relatively shallow planting to take advantage of higher soil temp near ground level but late planting temp is fav so deep planting to take advantage of soil moisture in deep

32. Vertical distribution of stink bugs on pre and post tasseling stages
Note: At R2 and R4, first 15 cm of x value is mostly due increased number of SB found on developing ear. See next slide

33. Stink bugs by plant part