2014 Spring: Updates and New Developments on the Sugarcane Aphid

in the Rio Grande Valley

Raul T. Villanueva, Danielle Sekula Ortiz Gabriela Esparza-Diaz

Weslaco, May 20, 2014

Sugarcane Aphid: Studies and survey of SCA in the LRGV

•Survey: 11 sites

•Transform® Studies: 3 grower fields

•Seed treatm.= 2

•Insecticide efficacy

•Economic threshold

•Cultivar resistance or tolerance

What are Sugarcane aphids?

• They are soft body insects that suck sap plant juices and produce a large amount of honey dew that can hinder a plants growth.

Sugarcane aphids

• All females and can live 28 days (range 10-37 days)

• 4 nymphal instars, can be adults in 5 days

• Nymphs can developed in 4.3 to 12.4 days

• Born alive (viviparous)

Life cycle

Exponential growth of populations Foundress

1st wk

2rd wk

3rd wk

Corn leaf aphid

Sugarcane aphid

Yellow sugarcane aphid

Greenbug aphid

Prefers young plants

Biotypes are reported

Other aphids species pests of sorghum

Yellow sugarcane aphid

Corn Leaf Aphid

Within these 2 past weeks we have been seeing an alarming amount of winged sugarcane aphids on the underside of the flag leaves.

Looking for Sugarcane Aphids

If SCA are not controlled, pest can move into sorghum panicles.

D. Sekula 2014

Seed treatment field trial 6 Different Treatments • Untreated 9562 • Untreated 9782 • Untreated 3707 • Cruiser 9562 • Cruiser 9782 • Poncho 3707 Was planted on February 17, 2014 Plants emerged on February 23, 2014 Began counts on February 28, 2014

0 500 1000 1500 2000

Untreated 9562Untreated 9782Untreated 3707

Cruiser 9562Cruiser 9782Poncho 3707

SCA counted on 25-Apr

0 500 1000 1500 2000

Untreated 9562Untreated 9782Untreated 3707

Cruiser 9562Cruiser 9782Poncho 3707

SCA counted on 2-May

0 500 1000 1500 2000

Untreated 9562Untreated 9782Untreated 3707

Cruiser 9562Cruiser 9782Poncho 3707

SCA counted on 16-May

• From February 28th through April 18th none to 1 or 2 SCA/plants were tallied.

• Other aphids species were found mainly the yellow sugarcane aphid and the corn leaf aphid, occasionally the green bug aphid

• Sugarcane aphids were mainly observed after April 25th.

No. of sugarcane aphids on sorghum with and without insecticide seed treatments

Seed treatments on two sorghum cultivars in potted plants Alex Navarro (intern from Step Up program: South Texas College)

• Two cultivars (Cv) with treated and untreated insecticides were planted on March 24th

Cv.1 + Cruiser & Cv.1-untreated Cv.2+ Poncho & Cv.2-untreated

• Plants germinated on April 1 • All these pots were kept in the green

house without SCA • Every week 4 plants of each treatment

were placed under a shade house and • Four aphids were placed in each sorghum

Cv every week from April 7th to May 19th

• The numbers of SCA were tallied every week

1. April 07 2. April14 3. April 21 4. April 28 5. May 05 6. May 12 7. May 19

4X/treatment

0

100

200

300

400

500

1-Apr 11-Apr 21-Apr 1-May 11-May 21-May

0

100

200

300

400

500

1-Apr 11-Apr 21-Apr 1-May 11-May 21-May

0

50

100

150

200

1-Apr 11-Apr 21-Apr 1-May 11-May 21-May

Seed treatments on two sorghum cultivars in potted plants N

º of

SCA

/pl

ant

1 week old

3 weeks old

5 weeks old

Week 1

Untreated Poncho

Week 3

Untreated Cruiser

SCA in the Rio Grande Valley: Spring 2014

• Sorghum was planted from February to mid March, probably most planting occurred in March due to rains and low temperatures

• SCA were not present in young plants in very few numbers until mid- April 2014

• By mid-April, we observed that sorghum fields that were planted in February were heavily infested by SCA

• Across the RGV, SCA populations started to appear on most of sorghum fields by the last week of April.

0

5

10

15

20

25

30

35

40

2-Mar 12-Mar 22-Mar 1-Apr 11-Apr 21-Apr 1-May 11-May 21-May

Numbers of SCA / plant : March 1st April 21st Numbers of SCA/ leaf: April 24t to this date

Mean SCA in 10 conventional & 1 organic field in the RGV

0 10 20 30 40 50

L1L2L3L4L5L6L7

Winged

0 10 20 30 40 50

L1

L3

L5

L7

L9

Winged

0 250 500 750 1000 1250

L1L2L3L4L5L6L7

Nymphs

0 250 500 750 1000 1250

L1

L3

L5

L7

L9

Nymphs

Booting, 05/09/14

Grain filling stage: 05/16/14

SCA distribution on leaves of two stages of sorghum plants without application of insecticides

• We found SCA on corn and sugarcane plants adjacent to sorghum in commercial fields

• SCA are producing offspring in corn plants • The same is occurring in sugarcane plants

SCA found feeding on sugarcane and corn

Sorghum

Corn

Sugarcane

SCA in sugarcane SCA in corn

• Winged SCA are producing offspring in both corn and sugarcane plants. We don’t know if SCA is going to persist on corn, become a secondary or severe pest.

• In sugarcane, we believe that SCA is going to be established permanently and it is well known that is a good vector of the yellow leaf sugarcane virus.

0

20

40

60

80

100

120

140

160

Winged Nymphs Winged Nymphs Winged Nymphs

Corn Sorghum Sugarcane

Suga

rcan

e ap

hids

/leaf

SCA (mean± SEM) on corn, sorghum, and sugarcane on May 14, 2014, after 1.6 in. of rain the previous day

Sugarcane aphids and the yellow sugarcane aphid in sugarcane plants

1. A spray with Transform® was completed in a Sorghum field (planted on Feb 2nd in Rio Hondo), on April 24th by broadcast: 0.75 oz/A

2. A spray with Transform® was conducted in North Edinburg on May 1st with hanging nozzles: 1.0 oz/A and 10 gal of water

3. A spray with Transform® was conducted in La Feria on May 7th by airplane: 1.0 oz/A and 5 gal of water

Control in commercial fields: 3 growers using different systems:

050

100150200250300350400450500

7-May-14 9-May-14 16-May-14 16-May-14

0

20

40

60

80

100

120

140

160

30-Apr-14 5-May-14 16-May-14

0

50

100

150

200

250

24-Apr 28-Apr-14 7-May-14 12-May-14 16-May-14

• Transform: 0.75 oz/A with 10 gal. of water

• Broadcast

•Transform: 1.0 oz/A with 10 gal of water

•Hollow-cone nozzles & drops

Transform: 1.0 oz/A Airplane with 5 gal water/A

Rio Hondo: 24-April

N. Edinburg: 1-May

La Feria: 7-May

• In general, SCA were effectively controlled by the Transform® sprays

• Grower Nº 2 had the best results although, data have not completely analyzed

• This grower couldn’t find aphids in his field for two weeks

• We are recommending large volumes of water for ground (>15 gal/A) and aerial (≥5 gal) sprays

Preliminary results on applications conducted by 3 growers using different systems:

0

200

400

600

800

1000

1200

1400

1600

Precount 7-DAA 14-DAA

Insecticide test in Weslaco, TX. Villanueva and Sekula Oct-Nov 2013 Field previously had been treated with 2 applications each of Warhawk® (2 pts/A), Prevathon® (2 pts/A) and Di-Syston® 8 (1.5 pts/A)

No.

of a

phid

s/le

af

Preliminary Results: Insecticide test-2014

0

50

100

150

200

250

300

350

400

450

3 daa

• Rains: we have not observed a decrease on the SCA populations due to rains, after1 and 1.6 inches on rain SCA were not affected

• We may need to adopt the name from Louisiana for this aphid: WHITE SUGAR CANE APHID to distinguish from the yellow sugarcane aphid.

• Seed treatments reduced SCA infestations earlier during the season

• Yield losses can be great if pest management is not conducted

• Natural enemies are no sufficient to control the high population growth of SCA

Final notes:

• Depending of the infestation level and developmental plant stage in sorghum we are recommending:

• 1 oz/A of Transform® followed by Dimethoate® or Lorsban® and if necessary another application of Transform®

• If there are heavy infestations two continuous spray of Transform® will be our recommendation, followed by Dimethoate® or Lorsban®

Final notes:

Acknowledgments • Thanks to the all sorghum growers and the

Cotton and Grain Producers of the Lower Rio Grande Valley for inviting us to their fields

• Beto Garza and all Texas A&M Agrilife Research who are providing great support for this program

• Drs. S. Armstrong, M. Brewer, M. Way, B. Rooney and D. Kerns, all collaborators in this program

• People that help collecting data: Sergio Davila, Alma Olguin, Cedric Galvan, Daniel Garcia, Joe Zamora, Justin Wendell, Alex Navarro and Alex Alaniz

• Thanks to industry for providing insecticide products.

• Many thanks to the Texas Grain Sorghum Board, and United Sorghum Checkoff for their encouragement to address this pest.

• Organic Transition USDA-NIFA grant