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 (rm ) 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 rm and λ recorded for C. noacki under experimental conditions indicate that this aphelinid has the potential to decrease populations of A. floccosus.
Highlights
There are 20 species in the genus Aleurothrixus Quaintance & Baker 1914 of which 80% occur in the Neotropical Region (Mexico, Central and South America, Caribbean Islands)
Specimens of C. noacki were initially collected in the field in November 2011 from a population of A. floccosus in an orchard located in Pica (20°29 ́S, 69°19 ́W; 1.348 m a.s.l.), Chile
Stock cultures of A. floccosus were kept on three species of Citrus: sweet orange (C. sinensis), Mexican lime tree (C. aurantifolia), and alemow (C. macrophylla), in the laboratory of the Facultad de Recursos Naturales Renovables (FRNR), Tarapacá Region
Summary
There are 20 species in the genus Aleurothrixus Quaintance & Baker 1914 of which 80% occur in the Neotropical Region (Mexico, Central and South America, Caribbean Islands). The species A. floccosus (Maskell) 1895, the citrus woolly whitefly, occurs in the following biogeographic zones: Nearctic, Neotropical, Palearctic West, Afrotropical, Palearctic East, Eastern and Pacific Islands. It is absent in Australasia and Hawaii (Evans, 2008). The eggs give rise to nymphs, which, after walking a short distance, insert their stylets into the mesophyll tissue of leaves. During their development they pass through four nymphal stages, during which thin waxy filaments are secreted that gradually cover the body. Prefer to feed and oviposit on the undersides of young leaves that sprout when their host trees are actively growing (Ripa et al, 1999; Giliomee & Millar, 2009)
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