2014 Spring: Updates and New Developments on the Sugarcane Aphid in the Rio Grande Valley

Transcription

1 2014 Spring: Updates and New Developments on the Sugarcane Aphid in the Rio Grande Valley Weslaco, May 20, 2014 Raul T. Villanueva, Danielle Sekula Ortiz Gabriela Esparza-Diaz

2 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

3 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.

4 Sugarcane aphids All females and can live 28 days (range 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

5 Exponential growth of populations Foundress 1 st wk 2 rd wk 3 rd wk

6 Other aphids species pests of sorghum Corn leaf aphid Yellow sugarcane aphid Prefers young plants Biotypes are reported Sugarcane aphid Greenbug aphid

7 Yellow sugarcane aphid

8 Corn Leaf Aphid

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

10 Looking for Sugarcane Aphids

11 D. Sekula 2014 If SCA are not controlled, pest can move into sorghum panicles.

12 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

13 From February 28 th through April 18 th 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 25 th. No. of sugarcane aphids on sorghum with and without insecticide seed treatments Poncho 3707 Cruiser 9782 Cruiser 9562 Untreated 3707 Untreated 9782 Untreated 9562 Poncho 3707 Cruiser 9782 Cruiser 9562 Untreated 3707 Untreated 9782 Untreated 9562 Poncho 3707 Cruiser 9782 Cruiser 9562 Untreated 3707 Untreated 9782 Untreated 9562 SCA counted on 25-Apr SCA counted on 2-May SCA counted on 16-May

14 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 24 th 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 7 th to May 19 th The numbers of SCA were tallied every week 4X/treatment 1. April April14 3. April April May May May 19

15 Nº of SCA /plant Seed treatments on two sorghum cultivars in potted plants Apr 11-Apr 21-Apr 1-May 11-May 21-May Apr 11-Apr 21-Apr 1-May 11-May 21-May week old 3 weeks old 5 weeks old Week 1 Untreated Poncho Week Apr 11-Apr 21-Apr 1-May 11-May 21-May Untreated Cruiser

16 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.

17 Mean SCA in 10 conventional & 1 organic field in the RGV Numbers of SCA / plant : March 1st April 21 st Numbers of SCA/ leaf: April 24t to this date Mar 12-Mar 22-Mar 1-Apr 11-Apr 21-Apr 1-May 11-May 21-May

18 SCA distribution on leaves of two stages of sorghum plants without application of insecticides Winged Booting, 05/09/14 Nymphs L7 L6 L5 L4 L3 L2 L1 L9 L7 L5 L3 L7 L6 L5 L4 L3 L2 L Grain filling stage: 05/16/14 Winged Nymphs L9 L7 L5 L3 L L

19 SCA found feeding on sugarcane and corn 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

20 Sorghum Corn Sugarcane

21 SCA in corn SCA in sugarcane 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.

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23 SCA (mean± SEM) on corn, sorghum, and sugarcane on May 14, 2014, after 1.6 in. of rain the previous day 160 Sugarcane aphids/leaf Winged Nymphs Winged Nymphs Winged Nymphs Corn Sorghum Sugarcane

24 Sugarcane aphids and the yellow sugarcane aphid in sugarcane plants

25 Control in commercial fields: 3 growers using different systems: 1. A spray with Transform was completed in a Sorghum field (planted on Feb 2 nd in Rio Hondo), on April 24 th by broadcast: 0.75 oz/a 2. A spray with Transform was conducted in North Edinburg on May 1 st 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

26 Rio Hondo: 24-April Transform: 0.75 oz/a with 10 gal. of water Broadcast Apr 28-Apr-14 7-May May May-14 N. Edinburg: 1-May 30-Apr-14 5-May May-14 La Feria: 7-May 7-May-14 9-May May May-14 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

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

28 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) Precount 7-DAA 14-DAA No. of aphids/leaf

29 Preliminary Results: Insecticide test daa

30 Final notes: 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

31 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

32 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