Oviposition Preference and Larval Host Range of the Sugarbeet Root Maggot (Diptera: Ulidiidae).

Abstract

The sugarbeet root maggot, Tetanops myopaeformis Röder (Diptera: Ulidiidae), is native to North America. However, its primary crop host, sugarbeet, Beta vulgaris L., was introduced to the continent from Europe in the late 19th century. This field and greenhouse research was conducted to compare the relative attractiveness of eight cultivated and wild plant species for oviposition by T. myopaeformis, and the suitability of these potential host plants for larval development to elucidate the potential native and current host range of this pest. Results indicated that females preferred ovipositing in soil immediately adjacent to or on the following plant species: sugarbeet; spinach, Spinacia olerocea L.; common lambsquarters, Chenopodium album L.; redroot pigweed, Amaranthus retroflexus L.; Palmer amaranth, Amaranthus palmeri S. Wats.; and to a lesser extent, spear saltbush, Atriplex patula L. Larval survival was greatest on spinach, sugarbeet, and spear saltbush, which all belong to the family Chenopodiaceae. Larval survival on these plants suggests that T. myopaeformis could have exploited wild chenopodiaceous plants or others within the order Caryophyllales before sugarbeet was introduced to North America. Low larval survival on common lambsquarters, redroot pigweed, and Palmer amaranth suggests that these species are suboptimal hosts, despite demonstrated attractiveness for oviposition. A general lack of oviposition preference by T. myopaeformis females was observed for sunflower, Helianthus annuus L., and common ragweed, Ambrosia artemisiifolia L. These results provide insights regarding the successful and somewhat rapid host preference shift by this insect to sugarbeet after cultivation of the crop began in the continent.