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

IPM OF CITRUS PESTS IN GREECE
47
carnea (Chrysopidae) Stephens is a notable aphid predator in Greece too
(Katsoyannos, 1996a).
Conservation of these agents includes management practices e.g. avoiding
chemical treatment, especially between mid-spring and early summer. Long-term
positive effects on the naturally-occurring biological control of citrus aphids are
obtained by preserving existing habitats, which function as reservoirs of the natural
enemies, or by creating new ones where needed.
In general, preserving sufficient plant diversity in the agroecosystem is
desirable, since it ensures the continuous presence of other aphid species which
serve as alternative prey of coccinellids during the summer scarcity of citrus
aphids. Other important measures include preserving hibernation sites and
preventing ants (Formicidae) from tending aphid colonies and disturbing the
aphids’ natural enemies. Although, these methods are indirect and their effect is
difficult to be evaluated, they are cost effective and easy to implement
(Katsoyannos, 1996a).
A classical biological control case involved the release of the predator
Harmonia axyridis Pallas (Coleoptera: Coccinellidae) in citrus in experimental
fields in Marathon (Attica), on Chios island, in Leonidion (Peloponnese) and in
Chania (Crete) in 1994. The predator was highly efficient against aphid population
outbreaks (Katsoyannos, Kontodimas, Stathas, & Tsartsalis, 1995). However, when
sampling was contacted between 1995 and 1999 there was no evidence for the
establishment of H. axyridis in the release sites (Kontodimas et al., 2008). Only
small colonies of overwintered adults (