Aphid pressure in the Yuma Valley has been quite low this season. However, alate (winged) green peach aphids have begun to show up on younger lettuce plants (1^st side-dress stage) and populations are beginning to colonize. Reports from Dome Valley and Wellton suggest that aphid populations are increasing there as well. This is common during February when produce acreage begins to rapidly decline and aphids tend to disperse to available crops. The key to effective aphid management with foliar insecticide is to initiate sprays at the time apterous (wingless) aphids begin to colonize. Of course, this requires diligent scouting and sampling. The UA action threshold for aphids recommends that applications be made when 10% of the plants sampled contain aphid colonies (4 or more apterous aphids). Fortunately, PCAs have numerous alternatives for foliar aphid control in the Aphid Control Chart 2012. Movento is highly effective and has the broadest-spectrum of activity against aphids commonly found on desert produce crops. In addition, because it is fully systemic, spray timing or application method is not as critical as with the other alternatives that are translaminar or require contact activity. Beleaf and Assail are also good foliar alternatives for aphids, and typically perform best with ground applications. Be sure to check that MRLs are established for export before using any of these products.

Remember: When in Doubt-Scout.

To contact John Palumbo go to: jpalumbo@ag.arizona.edu

For questions or comments on any of the topics please contact Marco Pena at the Yuma Agricultural Center.
College of Agriculture, The University of Arizona, Tucson, AZ.