[Edited_by_A._Ciancio,_C.N.R.,_Bari,_Italy_and_K.(Bookos.org)

CITRUS PEST MANAGEMENT IN ITALY
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Leafminers are most active from dusk to early morning. Soon after emergence
the female emits a sex pheromone that attracts males. Females lay 30–70 eggs
during their 2–12 days life span, deposited singly along the midrib on the lower
surface of new tender terminal leaves. Eggs hatch within 2–3 days at 26–27°C;
however, it may take up to 12 days at lower temperatures. Newly born larvae begin
feeding immediately in shallow, winding mines under the leaf cuticle. As the larva
increases in size, the mine becomes more visible because of the air that penetrates
and because of the central frass trace within the mine (Fig. 4). Larvae molt 4 times,
each larval stage lasting about 1 day, while the pupal stage lasts 7–10 days at 26°C.
Mature larvae pupate within the mine inside a silken chamber under the rolled edge
of the leaf. From egg to adult the life cycle takes about 15–17 days to complete at
26°C and 70–80% humidity, but it may last up to 7 weeks depending on temperature
and humidity conditions. Up to 13 generations per year occur in tropical areas. The
population dynamics and the activities of the Citrus leafminer vary in relation to
differences in climatic conditions and flushing of citrus trees. In Italy the spring
flushing escapes P. citrella infestation since temperatures are not suitable for the
leafminer development. The attacks of the pest occur during summer-fall.
Several predators, mainly spiders, bugs, lacewings and ants, have been observed
feeding on the pest (Browning & Peña, 1995). Besides, over 90 hymenopterous
parasitoid species, belonging to the families Braconidae, Encyrtidae, Eulophidae,
Eurytomidae, Eupelmidae and Pteromalidae have been reported (Heppner, 1993;
Hoy & Nguyen, 1997; Schauff, Lasalle, & Wijesekara, 1998). Among these species,
about 70 are considered as primary parasitoids and only 6 are classified as
preferentially living on P. citrella. Indigenous natural enemies, mainly parasitoids,
detected on the CLM never reached an effective control in all newly infested citrus
areas, such as Florida (Hoy & Nguyen, 1997), Israel (Argov & Rössler, 1996), Spain
(Garrido Vivas, 1995), Turkey (Uygun et al., 1996) and Italy (Barbagallo et al.,
1998; Caleca & Lo Verde, 1998; Giorgini, Pedata, & Viggiani, 1998).
Since in the native areas of the leafminer the host-specific enemies represent the
main biological mortality factor of the pest (Binglin & Mingdu, 1996; Morakote &
Nanta, 1996; LianDe, MinSheng, Jin, & Qing, 1999), a classical biological control
program has been started in 1995 in Italy by introducing exotic natural enemies.
Three Hymenoptera parasitoids [Ageniaspis citricola Logvinovskaya (Encyrtidae),
Quadrastichus sp. (now Quadrastichus citrella Reina & La Salle) and Citrostichus
phyllocnistoides (Narayanan) (Eulophidae)] have been introduced, reared and
released. Moreover, in 1998 the Australasian ectoparasitoid Semielacher petiolatus
(Girault) (Hymenoptera: Eulophidae) was recorded for the first time in Italy. The
species probably spread naturally after its introduction in other countries of the
Mediterranean basin (Mineo, Caleca, & Massa, 1998; Siscaro, Longo, Maugeri,
Reina, & Zappalà, 1999a).
Ageniaspis citricola (Fig. 5) is a poliembryonic koinobiont endoparasitoid of P.
citrella eggs and young larvae (Edwards & Hoy, 1998; Zappalà & Hoy, 2004). The
species shows several biological features which characterize effective parasitoids,
such as host-specificity, high reproductive rate (more than 180 eggs/female, femalebiased
sex ratio and short cycle), host discrimination capacity, high dispersal and
searching rate (Hoy & Nguyen, 1997; Zappalà & Hoy, 2004). Therefore, the