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Key words. Hymenoptera, Aphelinidae, Cales noacki, parasitism, life table, biological control, woolly whitefly, population ecology
Abstract. Biological parameters of the woolly whitefly Aleurothrixus floccosus (Hemiptera: Aleyrodidae) and its parasitoid Cales noacki (Hymenoptera: Aphelinidae) were determined at 25.0 ± 2.0°C, 50.0 ± 10.0% RH and a photoperiod of 14L : 10D on three different Citrus host plants. The percentage survival of A. floccosus ranged between 40.23 and 44.44%. The highest mortality was recorded in the first nymphal instar with mortalities ranging between 36.36 and 39.39%. on C. aurantifolia the total development time was 39.83 ± 0.68 days and the pre-oviposition, oviposition and post-oviposition periods 2.45, 10.68 and 1.68 days, respectively. Adult longevity was 15.0 days and average fecundity 73.27 ± 9.07 eggs. For C. noacki the pre-oviposition period was 0.8 days, oviposition period 4.38 days and post-oviposition period < 1 day. Adult longevity of C. noacki was 5.18 days and average fecundity 31.25 ± 2.87 eggs. The intrinsic growth rate (r^sub m^) of C. noacki (0.160) was significantly greater ( p < 0.05) than that of A. floccosus (0.076). The value of the finite rate of growth (λ) was also significantly ( p < 0.05) greater for C. noacki (1.173) than for A. floccosus (1.079). The larger values of r^sub m^ and λ recorded for C. noacki under experimental conditions indicate that this aphelinid has the potential to decrease populations of A. floccosus.
INTRODUCTION
There are 20 species in the genus Aleurothrixus Quaint- ance & Baker 1914 of which 80% occur in the Neotropical Region (Mexico, Central and South America, Caribbean Islands). The species A. floccosus (Maskell) 1895, the cit- rus woolly whitefly, occurs in the following biogeographic zones: Nearctic, Neotropical, Palearctic West, Afrotropi- cal, Palearctic East, Eastern and Pacific Islands. It is absent in Australasia and Hawaii (Evans, 2008).
The body and two pairs of membranous wings of adult females and males of these insects are covered with a white waxy substance. The adult female is about 1.5 mm in length with the male slightly smaller. In Chile, their host plants are orange, mandarin, lemon, grapefruit and lime. In recent years, it has also been recorded on lucuma and guava (Rojas, 2005; Luppichini et al., 2008). The eggs give rise to nymphs, which, after...