Age-specific life tables of Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae) and its parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae)

Abstract

Biological parameters of the California red scale (Aonidiella aurantii [Maskell] [Hemiptera: Diaspididae]) were determinedunder laboratory conditions at 3 different temperatures (20, 23, and 27 °C) on butternut squash (Cucurbita moschata Duchesne exLamarck) (Cucurbitaceae), while the biological parameters of its parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae) wereconducted at 27 °C. The survival of A. aurantii ranged between 80.0% and 88.3%. The highest mortality was recorded during the adultstage, with mortalities ranging between 12% and 20%. On C. moschata, the total development time was 93.1 ± 9.73, 81.8 ± 7.13, and65.7 ± 6.37 days, while the adult longevity was 54.65 ± 0.71, 47.05 ± 0.97, and 39.35 ± 1.07 days at 20, 23, and 27 °C, respectively. Theoviposition period of A. aurantii was 44.3 ± 0.51, 40.65 ± 0.41, and 34.5 ± 0.45 days at 20, 23, and 27 °C, respectively. Average fecunditywas 73.25 ± 1.827, 109.7 ± 3.569, and 129.35 ± 4.564 individuals at 20, 23, and 27 °C, respectively. For A. melinus, adult longevity was19.24 ± 0.73 days, and average fecundity 62.7 ± 2.81 eggs at 27 °C. The preoviposition period was 0.82 ± 0.05 days, oviposition periodwas 15.7 ± 0.52 days, and postoviposition period was 2.21 ± 0.09 days. The intrinsic rate of increase (rm) of A. melinus (0.188 ♀/♀/day)was significantly greater than that of A. aurantii (0.080) at 27 °C. These laboratory results demonstrated that A. melinus is an effectiveparasitoid for decreasing A. aurantii populations. Fecundity of A. aurantii and A. melinus was determined with the Enkegaard equation.The best-fit parameters of fecundity were calculated as a = 0.410, b = 0.099; a = 0.624, b = 0.098; a = 0.661, b = 0.091; a = 1.190, b = 0.179for A. aurantii at 20, 23, and 27 °C, and A. melinus at 27 °C, respectively.