Threshold Temperature and Heat Unit Summations for Seedcorn Maggot1 Development under Controlled Conditions2

The development of the seedcorn maggot, Hylemya platura (Meigen) (Diptera: Anthomyiidae), was studied in controlled-temperature chambers, and threshold temperatures and heat unit summations for egg, larval, and pupal development were determined. X-intercept estimates of the threshold temperatures for the egg, larval, and pupal stages were 2.42, 5.85, and 3.17°C, respectively. Similar results were obtained by using a least-variability method. An overall threshold temperature for egg-to-adult development was estimated to be 3.9°C. Heat unit summations above 3.9°C averaged 30, 204, and 142 for the egg, larval, and pupal stages, respectively; summations for egg-to-adult development were 376.