Life history and demography of Psyllaephagus zdeneki (Hymenoptera: Encyrtidae), a potential candidate for biological control of olive psylla, Euphyllura pakistanica (Hemiptera: Psyllidae)

Abstract

Life history and demographic parameters of Psyllaephagus zdeneki Noyes and Fallahzadeh (Hymenoptera: Encyrtidae) were studied on its host the olive psyllid, Euphyllura pakistanica Loginova (Hemiptera: Psyllidae). Experiments were conducted in a growth chamber at 20±1 °C, relative humidity of 60±5%, and a photoperiod of 16:8 (L: D) hours. Four different olive cultivars (Fishomi, Shenge, Oil and Yellow) were used to test possible host plant influence on parasitoid performance. The pre-imaginal developmental period of female P. zdeneki varied from 24.96 (on Fishomi) to 26.34 (on Shenge) days, and for males from 21.63 (on Fishomi) to 24.44 (on Yellow) days. Adult female longevity differed significantly among the four cultivars, ranging from 12.46 (on Fishomi) to 14.97 (on Shenge) days. For each cultivar, adult female longevity was significantly greater than male longevity. Life table parameters showed survival rates (l x ) in newly emerged females were 84.61, 82.25, 85.71 and 78.12% on Fishomi, Yellow, Shenge and Oil, respectively. Female egg deposition was highest on Yellow (138.4 eggs per female) and lowest on Fishomi (116.3 eggs per female). The highest and lowest intrinsic rate of increase were 0.28 (on Shenge) and 0.24 (on Oil), respectively. The mean generation time ranged from 14.6 (on Shenge) to 16.7 (on Oil) days. These results are discussed with respect to the potential impact P. zdeneki as a natural enemy of E. pakistanica, the most important pest of olive in the Fars province of Iran, as well as the influence of olive cultivar on parasitoid life table parameters.