Hulstia undulatella
Pest description and crop damage Caterpillar is a dirty brown color with a green tint. Larvae feed on petioles at the plant crown and along the side of the taproot. They remain by day just below the soil surface within soil-coated silken tubes that extend 2 to 6 inches from infested plants. They are most damaging as first-generation larvae during May. This insect has historically been an important pest in the area, but not in recent years.
Management-biological control
Several species of parasitoid wasps and flies attack crown borers, but their importance in reducing populations is unclear. Limiting insecticide use should favor these natural enemies. No commercial formulations of biological control products are registered for this pest.
Management-chemical control
Few products are registered against the sugar beet crown borer in sugar beet (Tables 1-2).
Note: See University of Idaho publication CIS 845, The Sugar Beet Crown Borer in Idaho, for more details.