consider when climatic conditions favor an epizootic. The timing for epizootics would most likely occur in the spring and fall. I have talked exclusively V. lecanii but there are other fungi that attack SCA. Several have been identified from diseased SCA on sorghum in Mexico. Unfortunately, there are no entomologists investigating fungal pathogens of SCA in the U.S. Predicting SCA outbreaks. Experiences with SCA over the past four seasons suggest SCA outbreaks commonly occur during dry conditions and moderate temperatures (mid-70’s to upper 80’s/low 90’s). The aphid demonstrates explosive reproduction potential under these cimatic conditions. Company Hybrid Maturity Alta AG1203 Medium-late B&H Genetics BH 4100 Medium Sorghum Partners SP 7715 Medium-full Warner W7051 Medium-late DKS48-07 DeKalb Medium REV9782 Terral Medium-full Hybrid resistance: Evaluation of commercial hybrids has been important for identifying/confirming an ever growing list of hybrids with resistance/tolerance to SCA. A short list of products identified as SCA ‘tolerant’ from 2016 field trials in north, central, and south Texas can be found in the table below. This is in no way an exhaustive list of sorghum hybrids with resistance to SCA but those that have been evaluated in Texas A&M AgriLife Research and Extension trials. Also, it is likely that SCA will occur on any of these hybrids but population growth will be much lower when compared to susceptible hybrids. Although SCA resistant hybrids are available, it is important that you select products that have the right agronomic mix to ensure a high probability of achieving production goals. The SCA can easily be managed with insecticides when routinely scouted and timely insecticide applications are made once the aphid reaches the economic threshold. Spray Tip Summary: SCA populations colonizing the the underside of leaves, often beginning at the base of lower leaves. We continue to see good efficacy of Sivanto and Transform WG, but we wanted to look at some of the commonly used and available spray tips to see if there were differences in spray coverage and canopy penetration, as those may be important points of consideration for expected efficacy of an insecticide application. This season, we were able to look at seven spray tips in two trials – one in Rosenberg in boot-stage sorghum on 40”
rows, and one in Corpus in headed sorghum on 38” rows. Spray coverage was measured at the base of the plant, lower canopy, mid canopy, and upper canopy. In the Rosenberg trial, which was made with a Spra-coupe at 10 gpa, there was no difference in spray coverage at any level of the canopy. In the Corpus trial, where the application was made with a plot sprayer at 20 gpa, there was no difference in percent coverage at the lower, middle, and upper canopy. However, at the base of the plant, percent coverage of the TeeJet TXR Conejet (8004) was more than double that of any other tip. Due to wet conditions when aphid populations were highest, we were unable to perform any insecticide efficacy studies comparing different spray tips. Hopefully we will be able to look at that next year to see if coverage and canopy penetration translate into improved efficacy. Closing thoughts. Often times we get caught up in our busy lives and forget to take time for ourselves, our families, and our friends. I hope all of you find time to spend with those closest to you during this holiday season. I would like to say “Thank you!” to all those that made this a great year for me and I am looking forward to another successful year in 2017. ACKNOWLEDGEMENT: I would like to thank John Gordy for reviewing this newsletter and providing the update on spray nozzel tip research. Better Yield in the Field You can now follow south Texas insect and production news on Facebook and Linkedin (Better Yield in the Field) and our website is coming together (). Check us out as we grow and expand our offerings. Robert Bowling, Ph.D. Assistant Professor and Agrilife Extension Entomology Specialist Texas A&M Agrilife Research and Extension Center at Corpus Christi 10345 Hwy 44 Corpus Christi, TX 78406 wk. (361) 265-9201