Thermal requirements for development of Diaprepes abbreviatus (Coleoptera : Curculionidae)

The root weevil Diaprepes abbreviatus (L.) was reared on artificial diet un der controlled conditions of temperature and humidity. The Lower thermal th reshold for development of neonate larvae was estimated to be 15 degrees C. The growth rate of neonate larvae increased exponentially with increasing temperature up to 30 degrees C. The growth rate of later instars, however, was suppressed at 30 degrees C and mortality was higher than that of larvae reared at 26 degrees C. Larvae reared as late instars only ( >56 d old ), or continuously at 30 degrees C, had increased mortality and produced small er adults than larvae reared at 22 and 26 degrees C. Larvae reared as late instars only (>56 d) or continuously at 22 degrees C had similar survival r ates compared with those reared at 26 degrees C, and they emerged as larger adults compared with larvae reared at 26 or 30 degrees C. The time require d for development from neonate to pupation was 125 +/- 3 d (mean +/- SEM, n = 38) at 26 degrees C. Duration of the pupal stage was inversely proportio nal to temperature between 22 and 30 degrees C. Pupal mortality was higher at 30 degrees C than at 22 or 26 degrees C. The total time required for a s ingle generation from oviposition to adult emergence was estimated to be 15 4 d at 26 degrees C and adequate humidity. Cumulative mean air and soil tem peratures and rainfall for a location inr central Florida were analyzed and presented for the period October 1991 through January 1999.