The development, reproduction, and life history of Encarsia citrina Craw were studied in the laboratory on San Jose scale, Quadraspidiotus perniciostis (Comstock), at constant temperatures of 15,17.5,20,25,27.5, and 30degreesC at 60-70% RH, and a photoperiod of 16:8 (L:D) h. Larval development did not occur at 15 and 30degreesC. Total developmental time varied from 22.7 d at 27.5degreesC to 47.4 d at 17.5degreesC. The lower development thresholds for larval, pupal, and egg to adult periods were 10.4, 6.3, and 9.0degreesC, respectively. The number of degree-days required to complete development was 434.8. The average longevity of adults ranged from 34.3 d at 15degreesC to 8.0 d at 30degreesC. The average fecundity of females ranged from 96.3 eggs at 20degreesC to 40 eggs at 17.5degreesC. Life table parameters were also determined at four constant temperatures (17.5-27.5degreesC). The intrinsic rate of increase, r(m), values for E. citrina ranged from 0.074 at 17.5degreesC to 0.176 at 27.5degreesC. The highest net reproductive rate, R-0, of 93.7 female offspring/female was estimated at 20degreesC. The mean generation time, T, ranged from 49.3 d at 17.5degreesC to 23.4 d at 27.5degreesC. The results of this study emphasize E. citrina survival and population growth under varied temperature conditions.
