Arizona Agriculture

Ayman Mostafa

After last year’s invasion of sugarcane aphid (SCA), Melanaphis sacchari in sorghum, PCA’s and growers in Arizona should be on the look out for this insect this season. The SCA can be confused with other aphids that are occasionally found on sorghum.  One is the corn leaf aphid, Rhopalosiphum maidis, that is small with bluish green body color with darker strips on the abdomen. The head, legs, cornicles, and antennae are black in color. The corn leaf aphid is usually found deep in the whorl of the middle leaf of preboot silage sorghum, but may also be on the underside of leaves, stems, or in panicles. Sorghum plants generally can tolerate many corn leaf aphids without being significantly damaged and control seldom is justified.

Another similar aphid is the greenbug, Schizaphis graminum. The greenbug is yellow to green in color with a dark green stripe down the middle ofits back. The greenbug can be found occasionally on sorghum and other grain crops, and there is no record of it causing significant damage in Arizona.

The following picture has the three aphids, SCA, corn leaf aphid and greenbug.

******For IMMEDIATE DISTRIBUTION******

Attention SORGHUM producers and PCAs! Through the Arizona Department of Agriculture, the state of Arizona has sought and received a Section 18 Emergency Exemption that permits the use of Transform WG insecticide within Arizona for the control of sugarcane aphid in sorghum. This new pest to Arizona is known to be highly invasive and difficult to control in sorghum with many older chemistries. Because of the imminent economic harm that this pest represents to our sorghum producers and the dairies that they serve, you may now apply for a permit from ADA and use Transform WG immediately to control sugarcane aphid. It is important that you follow and comply with all instructions provided by ADA and on the Section 18 label for Transform WG.

Steps

1. Obtain the ADA permit form online at: https://agriculture.az.gov/sites/default/files/Transform%20Use%20Application.pdf
2. Fill out and return the form to ADA licensing by email to: licensing@azda.gov
3. ADA will provide you a Section 18 label that you must maintain in your possession when using Transform WG under this exemption
4. Bring your approved permit to your local retailer and purchase Transform WG
5. Report all applications of Transform WG to sorghum on ADA’s Form 1080 and submit to ADA
6. Call ADA if you have any questions about the permitting, reporting or Section 18 label for Transform WG: 602-542-3578, anyone there can help you, including Carlos who is lead on this.

Our Thanks & Gratitude

We are grateful for the ADA’s work to facilitate the approval of this important Section 18 Emergency Exemption! On behalf of all stakeholders, we also thank:

• Director Mark W. Killian for requesting this Section 18 through his letter of request to US-EPA
• Mike Buben, Independent PCA, for supplying a letter of support and other economic risk information for the submission
• Ken Narramore, Independent PCA, and the Arizona Crop Protection Association for supplying a letter of support, economic data and other insights for the submission
• Greg Green, Sorghum Grower and PCA, for his letter of support
• KC Gingg, Sorghum Grower and Dairyman, for his letter of support
• Ana M. Kennedy Otto, Government Relations Manager, and the staff of Arizona Farm Bureau for supporting the submission package with a letter of support
• Brian L. Bret, State Regulatory Manager & Dow AgroSciences for supporting this request and moving materials into distribution swiftly for use by sorghum producers right away
• Drs. Ayman Mostafa and Peter Ellsworth, as “qualified experts”, and to the staff of University of Arizona’s Arizona Pest Management Center for the Section 18 submission by ADA and for helping to document the need required by this process.

Here are some links with local information about sugarcane aphid in sorghum.

• Sugarcane Aphid: A New Threat to Sorghum in Arizona.
• Pest alert: Heavy infestation of sugarcane aphid in Arizona, California sorghum.
• California & Arizona strategize on sugarcane aphid control.

Any products, services or organizations that are mentioned, shown, or indirectly implied do not imply endorsement by the University of Arizona.

Ayman M. Mostafa and Peter Ellsworth

University of Arizona, College of Agriculture and Life Sciences, Cooperative Extension

Over the last two weeks the UA Cooperative Extension IPM team received reports from pest control advisors of an aphid heavily infesting sorghum in many fields. The UA members of the Arizona Pest Management Center collected and field identified several samples from the Maricopa / Stanfield areas. The identification by Gene Hall UA Insect Diagnostician confirmed this invader as sugarcane aphid, Melanaphis sacchari. This is a new pest report for our state.

External identification characteristics of sugarcane aphid.

The infestation in many fields was overwhelming with the plants completely covered in stickiness from the honeydew excreted by the aphids.

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Given this heavy infestation, it is likely this aphid has been in the state for longer than just this year, although reports extended only as far west as eastern New Mexico last year. The sugarcane aphid is distributed over the South, Texas and New Mexico; where it is one of the most important insect pests of grain and forage sorghum. Until recently the sugarcane aphid fed only on sugarcane in the US, but in 2013 it was found feeding on sorghum in southeast Texas near the border with Louisiana. This sorghum-feeding sugarcane aphid biotype spread over north Texas, southern Oklahoma, Louisiana, and Mississippi. Sugarcane aphids survived the 2013 winter in south Texas and spread throughout much of Texas and 12 other southern states during the spring and summer of 2014. In 2015, the sugarcane aphid spread through Texas into Oklahoma and Kansas, eventually infesting 17 states. This area encompasses 90 percent of the US sorghum acreage (Click here for 2015 distribution of sugarcane aphid). Giving the severity of this infestation and the rapid distribution of sugarcane aphid in Texas, this could become a serious impediment to sorghum production in Arizona with serious consequences on forage and dairy industries in the state. Giving the challenges facing forage crops, like alfalfa and now sorghum, in the last few years, it is important to bring different interested parties in the forage and dairy industry together for discussion.

Click here for more information from Texas A&M Agrilife Extension and Research about identification biology, damage, sampling and management.