BIOLOGICAL AND LIFE TABLE PARAMETERS OF Myzus persicae (Salz.)(Hemiptera: Aphididae) IN RELATION TO HOST PLANTS AND THERMAL REQUIREMENTS.

Abstract

The developmental times, growth index, developmental rate, survivorship, thermal requirements, longevity, fecundity, and life table parameters of Myzus persicae (Sulzer) were investigated on apricot and peach at three constant temperatures 20, 24 and 28 o C. The data revealed that there were significant differences among the three temperatures in developmental time of nymphal instars. Meanwhile, there were no significant variations of the developmental time between different host plants at the same temperature. The survival percentage differed significantly among the three tested temperatures. The higher survival percentage was observed at 28 o C. Minimum developmental thresholds for nymphal instars and nymphal stage of M. persicae were not similar on apricot and peach. M. persicae required 57.47 DD to complete its development from first nymphal instar to adult female on apricot and 56.82 on peach. There were no significant variations in the pre-reproductive, reproductive, and post-reproductive of M. persicae when reared on apricot and peach at the three tested temperatures (20, 24, and 28 o C). Meanwhile, there were significant differences in the total longevity of adult females at three tested temperatures. The mean total fecundity (mean number of offspring/female) was 25.6, 30.3, and 60.0 nymphs on apricot, and 25.0, 28.0, and 59.0 nymphs on peach at 20, 24, and 28 o C, respectively with significant different. The duration of mean generation time (T) of M. persicae was 19.55, 13.56, and 8.38 days at the three tested temperatures on apricot and on peach, 20.01, 13.32, and 8.30 days on peach. The population could be doubled (DT) every 4.65, 2.84, and1.41 days at 20, 24 and 28 o C on apricot and 4.51, 2.86, and 1.43 days on peach. The values of gross reproductive rate (GRR), net reproductive rate (Ro), intrinsic rate of increase (rm), and finite rate of increase (λ) were higher at 28 o C than at 20 and 24 o C on both host plants. The survivorship (Lx) for female age was higher at 28 o C than at 20 and 24 o C on apricot and peach.