Forecasting Events in the Life Cycle of the Onion Maggot, Hylemya antiqua (Diptera: Anthomyiidae): Application to Control Schemes

Field studies in which onion maggot, Hylema antiqua (Meigen) (Diptera: Anthomyiidae), populations were monitored for adult emergence and peak activity, ovarian development, oviposition periods, and larval damage confirmed that a scheme of predictions of life cycle events based on day-degree accumulations could be used to determine reliably when sprays for control should be applied. The study was extended to include 11 onion growers who applied sprays based on these predictions. These growers obtained excellent onion maggot control with an average of 2 sprays during the growing season. Between 7 and 12 sprays had been applied by other growers and in other years.