Estimates of Loss of Yield Caused by the Wheat Stem Maggot to South Dakota Cereal Crops

Populations of Meromyza Americana Fitch were studied in cereal crops in South Dakota east of the Missouri River between 1964 and 1967. Losses caused by this insect were assessed, and attempts were made to develop methods of predicting losses. Losses were highest in spring wheat, followed in descending order by winter wheat, rye, and barley. No estimate of loss exceeded 9%; most estimates in wheat and rye fell between 1 and 3%. Damaged heads tended to occur singly rather than in aggregates. Estimates of populations of gravid females early in the season were not reliable indices to crop losses later in the year.