ALERT: sugarbeet root aphids

Published online: Aug 23, 2010 PNWPestAlert.net
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A new sugarbeets alert was posted to PNWPestAlert.net. Alert Information: UI Extension Entomologist Erik Wenninger is reporting that sugarbeet root aphids have been observed on the roots of common lambsquarters within sugar beet fields in Kimberly. Aphids have not yet been observed on adjacent beets, but they are expected to move to beets soon. Sugar beet root aphids may be pinhead sized and up to 5/64-inch (2 mm) long. They are pale whitish yellow and broadly oval to pear shaped. They secrete white, waxy strands, which give beets a distinctive "moldy" appearance. Severe infestations may reduce tonnage and sucrose levels. There are no rescue insecticide options available; when root aphids are found attacking beets, cultural control practices should be followed (see below). Sugarbeet root aphids feed on the roots of sugarbeet plants, but will also attack closely related species, including spinach, table beets, common lambsquarters, and pigweed. Pulling alternate weed hosts found within or adjacent to sugarbeet fields and inspecting the roots for aphids and distinctive wax secretions may be a convenient method of preliminary scouting. If aphids are found on weeds, then nearby sugar beets should be examined as well. When root aphid infestations are found on sugarbeets, careful maintenance of a proper irrigation schedule is the single most important cultural control tool available. Damage by root aphids is exacerbated when plants are drought stress (conversely, diseases are encouraged when plants are over irrigated), so an optimal irrigation schedule will enhance the ability of the crop to resist attack from aphids. In addition, good management of alternate weed hosts (including lambsquarters, dock, pigweed, and prostrate knotweed) is important, and care should be taken to avoid contaminating uninfested fields with soil or irrigation water from an infested field. The use of resistant sugarbeet varieties may be considered for future plantings. To view the full alert, and to download any attached files, please go to www.pnwpestalert.net