Mortality and Aberrant Development of the Sugarbeet Root Maggot (Diptera: Otitidae) after Exposure to Steinernematid Nematodes

Third instar larvae of the sugarbeet root maggot (Tetanops myopaeformis von Röder) were challenged with three strains of Steinernema carpocapsae (Weiser), two strains of S. feltiae (Filipjev), and one strain of S. glaseri (Steiner). Steinernema carpocapsae "SCANMASK" (1.3%) showed the lowest level of infectivity, followed in ascending order by S. carpocapsae "ALL" (2.8%), S. carpocapsae "252" (4.4%), S. glaseni "326" (5.5%), S. feltiae "SN" (6.4%), and S. feltiae "UK" (8.6%). In several of the nematode challenges of diapaused larvae, resulting pupae gave rise to adult flies with gross abnormalities. Microscopic examination of these pupae gave no indication of nematode infection or an ensuing septicemia. Overall, 24.4% of the imagos arising from nematode-challenged larvae gave rise to aberrant adults. We have attributed these aberrant adults to an accelerated metamorphosis. These aberrant flies did not produce eggs, although mating attempts were observed.