Bionomic and life table parameters of olive psyllid, Euphyllura straminea on olive seedlings under three constant temperatures.

Abstract

Bionomic and life table parameters of Euphyllura straminea Loginova were carried out at three constant temperatures (20ºC, 25ºC and 30ºC) on olive seedlings throughout one complete generation. Durations and percentage of mortalities for different developmental stages were estimated. Results revealed that egg incubation period, durations of nymphal stage and the five nymphal instars were decreased as temperature increased from 20ºC to 30ºC. Moreover, the highest percentage of mortality was occurred throughout 1st 4th nymphal instar at 30ºC, while the lowest percentage was occurred throughout nymphal instar. The values of zero of development for different developmental instars were 11.96, 13.30, 13.40, 13.10, 15.40 and 14.50 for egg 1st, 2nd , 3rd and 5th nymphal instars and nymphal stages, respectively. Results showed that the highest percentage of , 4th adults' emergence and sex ratio were occurred at 25ºC being 92.6 % and 1: 1.8, respectively. Also, results revealed that temperature had highly significant effects on durations of pre oviposition, oviposition and post-oviposition periods as well as adult longevity for both sexes. These durations were decreased as temperature increased from 20ºC to 30ºC. Female fecundity and egg hatchability were affected by prevailing temperature. The highest numbers of deposited eggs was 277.2 eggs/ female and egg hatchability was 87.66 % occurred at 25ºC. Results of life table parameters showed that the highest percentage of egg hatchability and the lowest percentages of apparent and real mortality as well as the highest numbers of adult’s survival were occurred at 25ºC. The highest net reproductive rate (R) was occurred at 25ºC being 88.91 eggs / female. The shortest generation time (GT) was 46.66 day occurred at 30ºC. Both intrinsic rate of increase (rm) and finite rate (λ) were occurred for those reared at 25ºC and 30ºC. Both values were 0.03 and 1.03 occurred at the two tested temperatures. The shortest population doubling time (Dt) was occurred at 25ºC being 27.95 days. All these parameters revealed that 25ºC seemed to be optimal temperature for rearing E. straminea.