Sorghum Tips

Being Practical—and Correctly Informed—about Sugarcane Aphid

High Plains & Rolling Plains

High Plains growers are getting their first ‘real’ taste of sugarcane aphid (SCA). It isn’t sweet. It is ironic that High Plains growers might have more issues in 2015 than did most Central & South Texas growers where SCA had to deal with a lot of cool, rainy weather, which seems to suppress the aphid, allow beneficials to keep it in check, etc. Dr. Ron Schnell (College Station) and Dr. Josh McGinty (Corpus Christi), others report that at most 10%, maybe 15% of acres in their areas were sprayed for SCA.

Where will we be in the High Plains? Especially since SCA was first reported here up to two months sooner than 2014.

As of August 5 a few thousand acres in the High Plains have been sprayed for SCA. I am not sure that all of these were the right acres. Indications, including comments from regional IPM agents, are that some acres were sprayed below threshold (misinformation, lack of proper scouting, poor recommendations from private scouts?), and some acres need spraying but haven’t been. Premature spraying is not a good idea as 1) you perhaps use some of your allotted insecticides sprays (especially Transform, which you can only spray twice), and 2) it is possible that you actually might not reach threshold.

I urge all—producers, scouts, chemical dealers—in your area:  be aware of SCA. There does appear to be some misinformation regarding SCA in the High Plains. All High Plains and Rolling Plains fields should be scouted at least weekly to identify the Presence of SCA. Here are two cases that highlight what can happen or what some producers might have in mind (nonchalance?):

  • Producer on Lynn-Dawson border:  He knew SCA was in the area (Presence), but since he planted a so-called ‘tolerant’ hybrid in early (mid-May) in the cropping season (a good strategy), he wasn’t too worried about things, or at least hadn’t gotten to follow-up on a couple of his own fields that he found some aphids about July 13. He did not check fields again until Wednesday, July 29, in late bloom (16-day gap), and the SCA’s were so bad that he actually wondered if he could save his field (he can). He sprayed 1,100 acres, all at or above threshold (50-125 aphids per leaf). This grower has other fields about 10 miles to the west that are a different purported tolerant hybrid, and though he hasn’t yet seen aphids there, he sure needs to check at least once per week, then go to two 2X/week once the initial presence is confirmed. What if you were this farmer’s neighbor and you have grain sorghum?—Do you need to spray? No, scout first!
  • August 3 I made a field visit to a producer at Wilson, Lynn Co., to assess another issue in grain sorghum. I asked the farmer if he was checking any for SCA on his grain sorghum.  “Some.”  He knows a few farmers are spraying, he has heard it is worse in one company’s hybrids (I don’t think so; no one brand is more susceptible than others—all hybrids, even those designated as ‘tolerant’ are still susceptible to SCA, e.g. the first grower above).  After we finished, I looked at two of his fields, and a neighbor’s across the road.  SCA on about 10% of plants.  Needs to be scouted every 3-4 days.

Kerry Siders, Hockley/Cochran/Parmer Co. IPM agent, k-siders@tamu.edu, (806) 894-3150, is in the midst of ten Extension meetings on SCA. Kerry noted August 4th that fields are highly variable with SCA, and he has yet to report a field in his service area that has reached the threshold for spaying. But a few of his growers have been told by scouts they have SCA (threshold or not) and told to “spray it all.” Whoa! That was bad advice. Kerry told his producer to ask the scout for the field SCA counts to verify what levels of SCA were in the field. Also, Kerry advised that you CAN NOT adequately evaluate SCA on field edges—you will have to walk the field. In one case he walked several hundred feet into the field, found a major hot spot with several plants with 1,000 or more SCA per leaf, but then in all directions from this hot spot couldn’t find ANY more SCA! Just as we would not want to spray a field at threshold SCA (or worse) late; likewise, we do not want to spray a field early. Field results will be variable. Hot weather fires off SCA, but cloudy, cool days like Saturday, August 1, in the South Plains can suppresses SCA growth according to Siders. Siders did note, however, that SCA is with us to the end of the season in the High Plains. Growers that planted early, knowing that SCA might be an issue, are probably glad they did so (this is similar to how we would manage for sorghum midge, by the way).

A special note for the Texas Panhandle — Common current aphids are not SCA:  Several SCA reports from the east and northeast Texas Panhandle proved to be not SCA but yellow sugarcane aphid (these are distinctly different). Yellow sugarcane aphids can be a damaging pest, but it is managed differently than SCA. For information on this insect review the Texas grain sorghum insect and pest guide (Extension publication E-1220) online here.

Sugarcane Aphid Resources—Summary & Key Documents, including “Scout Card”
This is a summary of key documents that entail numerous aspects of sugarcane aphid (SCA) biology, scouting, control options, etc. The documents listed below are found across four AgriLife websites so this will bring these to one location for your convenience.*Click the colored title to be directed to the website.

1) Sugarcane Aphid Management Guide, e.g. “The Sugarcane Aphid: A New Pest of Grain and Forage Sorghum” (April 25, 2015). Comprehensive guide to SCA in Texas grain sorghum.

2) Sugarcane Aphid Newsletter, e.g. Crop Management Newsletter 23:6,  (July 1, 2015). A good Dawson-Lynn summary from Tommy Doederlein on expectations with the earlier arrival of SCA in the South Plains (initial confirmation late June 2015 relative to 2014 (identified about 2 months sooner this year).

3) Sugarcane Aphid Scouting School PowerPoint,  (early 2015?). Summary of tips including specifics regarding labeled SCA insecticides Transform and Sivanto.

4) Recognizing the Sugarcane Aphid, (February 27, 2015). How to distinguish SCA from greenbug, corn leaf aphid, and especially the yellow sugarcane aphid (a different pest, which is currently prevalent in Texas Panhandle grain sorghum, late July 2015). You will need a good magnifying glass (and your reading glasses if you use them) to simplify aphid identification.

5) Sugarcane Aphid Field Scout Card, (April 2015). You can use this in the field to guide scouting, estimate SCA infestations and aphid numbers, etc. (approximate numbers without actually counting to comparable reference pictures).

6) Insecticide Selection for Sorghum at Risk to Sugarcane Aphid Infestations, (April 2015). The labeled and common pyrethroid insecticides for other common grain sorghum insects reduce beneficial insect populations thus enhancing potential increases in SCA. Options are discussed.

Updated News and Blog Post Notifications
High Pains growers, it is not too late to sign up on the right side of the page at http://txscan.blogspot.com/ to receive regular SCA news and blog update notifications to your e-mail.

Upcoming Texas A&M AgriLife Extension SCA Meetings in the High Plains
Friday, August 7
Brownfield – Terry County Extension Office – 8:30 am
Monday, August 10
Morton – Cochran County Activity Room, Cochran Co. Extension Office – 8:30 am