The latest Arizona Vegetable Integrated Pest Management Update from the University of Arizona (UA) Cooperative Extension in Yuma, Ariz., released Jan. 12, 2012.

Foxglove aphids begin to colonize desert produce

By John Palumbo, UA Research Scientist and Extension Specialist

Until recently, aphid pressure has been relatively light in most areas throughout the desert Southwest. There have been a few reports of alate (winged) green peach aphids on a few plants with minimal colonization.

However, last week a local pest control adviser brought in some aphids for identification from a celery field in the Yuma Valley. The terminal area of the plant had several immature apterous (wingless) aphids colonized within the crown of the plant. The aphids were identified as foxglove aphids (FGA), Aulacorthum solani.

In addition, FGA have been found on untreated lettuce at the Yuma Agricultural Center.

The apterous forms are pear shaped and the abdomen is green in color. The cornicles are moderately long, thin, and tapered; varying in color from almost colorless to dark and with dark tips. The distinguishing characteristic of FGA is the dark green patches at the base of the cornicles.

In lettuce, FGA are serious pests of all spring lettuce types (leaf, romaine, and head) and typically begin showing up in January under mild weather conditions and are generally most active in February and March.

The FGA is more mobile than green peach aphid and tends to disperse more throughout the plant. However, insect tends to colonize intensively in heads and hearts once plants begin to cup.

FGA is a serious pest of celery primarily colonizing the young growth protected within the plant. They contaminate celery hearts at harvest rendering it unmarketable.

An application of Movento (spirotetramat) at 5 ounces/acre is the recommended insecticide for FGA in celery and in lettuce once plants have begun to form heads.

FGA does not colonize cole crops or spinach.

For more information on FGA and other aphid species found on leafy vegetables, click on this link: Insect Management on Desert Produce Crops: Aphids.

Remember, when in doubt , scout.

Contact Palumbo: (928) 782-3836 or jpalumbo@ag.arizona.edu.