Cowpea Curculio in Alabama: Lessons from the Field (Part 1)

Ayanava Majumdar, Ph.D.Ext. Entomologist

251-331-8416www.aces.edu/vegetableipm

Neil KellyRegional Extension Agent

Larry WellsDirector, Wiregrass Research and

Extension Center

Leaffooted bugs(Phyllopus spp.)

Aphids(Aphis spp.)

Thrips(Frankliniella spp.)

Frequent pests of southern pea

Caterpillars(various species)

Cowpea curculio(Chalcodermus aenus)

Potential crop loss or

contamination : 50% or more

Life cycle of cowpea curculio

Eggs are oval, white,

and laid inside the pea pods.

Larvae are pale yellow

and legless.

Body has stiff bristles.

Pupation occur in the

soil at about 1 to 3 inch depth

inside a pupal cell.

Adults are black with elongate

mouthparts. Dorsal surface appears dotted.

Images: ACES, UF/IFAS

Pod damage from cowpea curculio

Adults feed and lay eggs inside the pods.Larvae cause irreversible crop damage in a few weeks.

Curculio counts on southern peas(Headland, AL, 2015)

0

4.5

2.5

0

3

2.3

0.25

1.5

2

0

3.3

1.3

0

4

1

INDEX:

Untreated check

Botanigard 1qt/A + Bifenthrin 3.2 oz/A

Bifenthrin 6.4 oz/A + PBO8 8 oz/A

Beseige (lambda-cy + chlorantraniliprole) 10 oz/A

Botanigard 1 qt/A

Adults may become active in May and June if southern peas are available early in the season.Repeat weekly treatment before flowering stage delayed pod infestation in late July.

Cowpea variety: “Elite”

4 DAT3 (July 20) 7DAT4 (July 30) 7DAT5 (Aug 6)

4.6 5.2

34.9

5.1 4.9

36.5

3.9 4.6

43.5

4.75.6

39.7

4.1 4.6

40.1

Cowpea variety: “Elite”

Sample size = 20 pods per plot

Pest outbreak

Number of stings on pods(Headland, AL, 2015)

INDEX:

Untreated check

Botanigard 1qt/A + Bifenthrin 3.2 oz/A

Bifenthrin 6.4 oz/A + PBO8 8 oz/A

Beseige (lambda-cy + chlorantraniliprole) 10 oz/A

Botanigard 1 qt/A

Pre-bloom and bloom treatments appear to delay pod stinging by the first generation of curculios. However, second and overlapping generations may cause extensive stinging on pods.

July: 5 stings per pod (untreated check)

August: 35 stings per pod in untreated check

Rapid increase in pod damage by cowpea curculios

Pest outbreak

4 DAT3 (July 20) 7DAT4 (July 30) 7DAT5 (Aug 6)

14.9

27.0

79.4

17.919.4

82.6

11.8

21.0

91.5

14.9

23.5

91.4

13.7

28.5

88.3

Percent seed damaged due to curculios(WREC Headland, 2015)

Pest outbreak

Sample size = 20 pods per plot

Cowpea variety: “Elite”INDEX:

Untreated check

Botanigard 1qt/A + Bifenthrin 3.2 oz/A

Bifenthrin 6.4 oz/A + PBO8 8 oz/A

Beseige (lambda-cy + chlorantraniliprole) 10 oz/A

Botanigard 1 qt/A

Pre-bloom and bloom treatments appear to delay seed damage by the first generation of curculios. Seed damage and contamination in test plots averaged 85% in August.

Not all varieties are favored by cowpea curculios. Plant southern peas in relation to neighboring crops to reduce risk.

Start insecticide treatments two to three weeks ahead of flowering.

Mix PBO (synergist) with synthetic pyrethroids and rotate chemistries.

Spray frequently at 3-5 d intervals and follow the pesticide label.

Don’t quit spraying insecticides too soon! Scout intensively and keep records!

Overall lessons and IPM recommendations

There is a new sampling method available that can help detect the adults (developed by UGA). The yellow trap has not been evaluated in Alabama.

Check weeds around the field such as narrow-leaved vetch, purple cudweed, etc.

Look at the cowpea plants as they develop and intensify scouting when flowering begins.

Scouting for cowpea curculios

Capinera, J. 2009. Cowpea curculio. UF/IFAS Bulletin Number EENY-223. [Online] http://entnemdept.ufl.edu/creatures/veg/bean/cowpea_curculio.htm

Riley, D. G., A. Sparks, Jr., and J. Kicklighter. 2014. Cowpea curculio in southern pea. UGA Circular 1038. [Online] http://extension.uga.edu/publications/files/pdf/C%201038_1.PDF

Consult a Regional Extension Agent in Alabama for developing a site-specific IPM recommendations. Visit www.aces.edu/vegetableipm for additional IPM videos.

References

Commercial Horticulture REAs providing consultation to producers: Neil Kelly, Mike Reeves, James Miles, Doug Chapman, Chip East, Bethany O’Rear, Gary Gray

Video production team: Luke Knight, Ann Chambliss, Kristin Hinnant

Funding agencies:

Acknowledgement