The thermal constant for timing the emergence of the Red Palm Weevil, Rhynchophorus ferrugineus (Oliv.) (Coleoptera,Curculionidae)

The pupal duration of the red palm weevil, Rhynchophorus ferrugineus (Oliv.) at two different temperatures revealed that the thermal threshold is –?2.3?°C, while the thermal constant is 423 degree days. Around 20.7 cycles of weevil emergence per year have been predicted in Egypt. A temperature between 44?–?45?°C was found to be the higher threshold at which the pupae are killed. The heat units required for the pupal development were utilized to predict the dates of adult emergence throughout the year.