General Situation Very little rain fell on the area this week as we were treated to 60 degree mornings and finally reached 90 degrees today. If the cool weather continues it may prove difficult to finish out the crops as we had hoped, but for the most part both dryland and irrigated fields are looking good in the region. The 10-day forecast is more of the same, with little to no precipiation, lows in the 50s and highs in the 80s.

From the Field Cotton

Cotton aphids are still sticking around Lubbock and Crosby fields. Beneficials have helped in many instances, but some fields are still hovering at threshold and require treatment. This is especially true if bolls are starting to crack – it doesn’t take more than a few aphids to make honeydew that will cause sticky lint!

While it appears most of the bollworms are in sorghum now (see more below!), it is still good to keep an eye out for bollworms in both Bt and non-Bt cotton. This cooler weather lately means that we will have to watch out for insect pests longer than usual because we don’t have the heat units required to get cotton to that safe stage. Some of the earliest planted cotton fields just started cracking bolls this week and I imagine more will follow suit soon.

Sept 1, 2017 Vol. 2 – No. 14

Southern High

Plains IPM

Integrated pest management

updates in Lubbock and Crosby

Counties from Katelyn Kesheimer

Rainfall for last 7 days in Lubbock and Crosby counties. Pin on left is Lubbock Co Extension office and pin on right is Crosby Co Extension office. Map: http://water.weather.gov/precip/#

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Sorghum – Sugarcane Aphids

Sugarcane aphids are showing no signs of slowing down; fields all over Lubbock and Crosby county are requiring treatment. Additionally, winged adults are re-infesting fields that have already been sprayed and continuing to reproduce. It is crucial that you scout your sorghum no matter what stage it is.

Sorghum – Worms

We had been picking up some moderate worm activity recently in sorghum from both fall armyworm and bollworm/corn earworm. This week, however, we visited some fields in southern Lubbock county that had extremely high worm numbers. The following is written by Dr. Pat Porter, Extension Entomologist, and discusses some of the control options and complications with this pest complex. Feel free to contact me if you have questions.

Sugarcane aphids on the underside of a leaf this week in Lubbock. Their reproductive capability is no joke.

We encountered fields at panicle exertion or already booted that had as many as six worms per head, with an average of 2-3 mid-sized worms being the norm. For the most part these were fall armyworms in southern Lubbock County, but corn earworms seemed to increase in frequency as we went south. In a field 6 miles west of Tahoka we were seeing something like the 70% fall armyworm and 30% corn earworm.

Normally the control options for caterpillars would be a pyrethroid like 6.0 oz of Karate with a pint of Lorsban added to the tank. Pyrethroids are not very effective on fall armyworms over 1/2 inch in size, so the Lorsban would act as a synergist. Area crop consultants like Greg Cronholm, former Extension Agent IPM, have used this combination to good effect. HOWEVER, WE FOUND SUGARCANE APHIDS IN ALL OF THESE FIELDS. The use of a pyrethroid and Lorsban would eliminate the biological control agents in the field that are suppressing the sugarcane aphid population.

What we have now in these areas is a real problem. By rights we should go after the worms with a soft insecticide that does not kill the biological control agents that keep sugarcane aphid in check. These insecticides would be Blackhawk or Prevathon. Blackhawk is approximately half the price of Prevathon, but DowAgroSciences has told us that there are no supplies of Blackhawk left in the warehouses because of brisk sales this year in the mid-South. So that leaves Prevathon, which is excellent on both caterpillar species. However, an application of 14 oz/acre of Prevathon, the lowest labeled rate, would cost on the order of $18 per acre + application costs. We cannot recommend less than labeled rates, but area Independent Crop Consultants tell us that 10 oz of Prevathon with 5 GPA by air provides good control of both caterpillar pests. This rate would cost approximately $12.80 per acre + application costs.

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Upcoming Events – Crop Tours Thanks to Mary Jane Buerkle at Plains Cotton Growers for this list!

September 6 - Texas Alliance for Water Conservation Field Day, 8 a.m.-2 p.m., AgriSearch Farm near Edmonson (Hale County). Site directions and more information available at http://www.tawc.us.

September 6 - Americot/NexGen Field Day, 10:30 a.m., Texas Tech Quaker Farm, 200 N. Quaker (just north of the intersection of Fourth Street and Quaker Avenue), Lubbock. Lunch to follow tour. Questions: contact any NexGen sales representative.

September 7 - On-Farm Water Efficiency Field Day hosted by Crop Production Services and North Plains Groundwater Conservation District, 9:30 a.m.-2 p.m., North Plains Water Conservation Center, 6045 Co. Rd. E., Dumas. More information available at http://northplainsgcd.org/events/.

September 12 - Americot/NexGen Hockley/Cochran County Field Day, 4 p.m., meet at Len Stanley's barn. Questions: contact Mark Foster, Paxton Pugh or Gary Sanders.

September 14 - PhytoGen/Enlist Field Tour, Shallowater Community Center, 1009 Avenue H. Registration 7:30 a.m., tour begins at 8 a.m. Lunch provided at conclusion of tour. Questions: Ken Legé, 806-773-7310, or your local PhytoGen sales rep.

If one chooses to follow the pyrethroid + Lorsban path in a field with sugarcane aphids, then it is likely that a follow-up application will be needed for the aphids; at least 5 oz/acre of Sivanto or 1.25 oz/acre of Transform. But this is not a given; the aphids south of Lubbock County do not seem to be increasing as fast as they did in years past.

At this point we do not know what to recommend with so many headworms in the system and aphids in the field; it comes down to economics. The fundamentals say to treat the insects that reach the economic threshold and try to conserve the beneficial species that suppress other pests. By the book we would recommend treating the worms with a "soft" insecticide like Blackhawk or Prevathon, and then monitor sugarcane aphids closely and treat them if necessary. Stepping away from the book, we would go after the headworms with Karate and Lorsban and then add 5 or more ounces of Sivanto to control the sugarcane aphids, but this cocktail would be very expensive. We know there are no good options here, and we can't predict the future.

We have a sorghum headroom treatment threshold calculator here: http://bug.tamu.edu/apps/sorghumheadwormcalculator/index.html. Our written thresholds are here on page 23: http://lubbock.tamu.edu/files/2015/08/Sorghum_Guide_2007.pdf.

Another unknown is sorghum midge. The late planted crop is at risk, and with Blackhawk out of the picture we will have to resort to pyrethroids, which in turn will increase the risk of sugarcane aphid while not being much use on fall armyworm.

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September 20 - Perryton Field Day hosted by North Plains Groundwater Conservation District, Ochiltree County Expo, 402 Expo Drive, Perryton, 9:30 a.m. More information available at http://northplainsgcd.org/events/.

September 21 - Americot/NexGen Field Day, 10 a.m., AgriSearch Farm near Edmonson (Hale County). Questions: contact Gary Sanders or Jerry Montgomery.

September 26 - Deltapine Field Day, 11 a.m., Robbie Harkey Farm, Interstate 27 Exit 43, Hale Center. More information: Alyssa Spruill, (806) 500-5003.

September 26 - Americot/NexGen Lubbock/Lynn County Field Day, time TBA, Matt Caswell Farm. Questions: contact Cody Reep, Dale Schaffner or Hayden Alexander.

September 28 - Bayer CropScience West Texas Field Day, location in the Lubbock area to be determined. Questions: contact your local Bayer CropScience sales representative.

October 3 - Swisher County Cotton Tour, 9 a.m., Kress. Questions: John Villalba, Swisher County CEA-Ag/NR, (806) 995-3721.

Southern High Plains IPM is a publication of the Texas A&M Agrilife Extension Service IPM Program in Lubbock and Crosby Counties. Educational programs of Texas A&M Agrilife Extension Service are open to all citizens without regard to race, color, sex, disability, religion, age, or national

origin. The information given herein is for educational purposes only. References to commercial products or trade names are made with the understanding that no discrimination is intended and no endorsement by Texas A&M Agrilife Extension Service is implied.

The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating

Katelyn A. Kesheimer, Ph.D.

Extension Agent – Integrated Pest Management 916 Main Street, Lubbock, Texas, 79404

Questions, comments, concerns?

Office: 806-775-1740, Fax: 806-775-1758, Mobile: 806-474-5092

Email: katelyn.kesheimer@ag.tamu.edu Lubbock Co. Extension: http://lubbock.agrilife.org

Crosby Co. Extension: http://crosby.agrilife.org

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http://lubbockcountyipm.blogspot.com