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

IPM OF CITRUS PESTS IN GREECE
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2.2.1. Sampling and Monitoring
An efficacious monitoring system is prerequisite for having a successful
forecasting/warning system for citrus scale insects. A number of monitoring tools
are available for citrus scales, which are used in Greece. Sex pheromone traps are
utilized for the detection, monitoring and forecasting outbreaks of the California
red scale A. aurantii. White sticky sex-pheromone baited traps are used for
monitoring purposes of other armoured scales. Pheromone traps are also available
for the citrus mealybug P. citri. Field observations and sampling are necessary for
the detection of other citrus scales. Various detailed sampling schemes have been
proposed for this area of concern (Katsoyannos, 1996a).
2.2.2. Biological Control
An extended trial has been directed toward classical biological control of citrus
scales in the past so Greece is a good example of a country where native scale
insects have been controlled by exotic natural enemies, both parasitoids and
predators. Eleven parasitoid species have been introduced, seven of them providing
sufficient control whereas several predators associated with classical biological
control of scale insects are frequently present in the Greek citrus orchards.
Five parasitoid species, Aphytis melinus DeBach, A. lingnanensis Compere,
A. coheni De Bach Compere (Hymenoptera: Aphelinidae), Encarsia perniciosi
(Tower) (Hymenoptera: Aphelinidae) and Comperiella bifasciata Howard
(Hymenoptera: Encyrtidae) were introduced and released in field trials against
A. aurantii between 1962 and 1970. A. melinus is the leading parasitoid targeting
the California red scale but its efficacy is reduced in cases of outbreaks.
Comperiella bifasciata had a minor establishment whereas A. lingnanensis and A.
coheni failed to be established (Katsoyannos, 1996a).
Aphytis lepidosaphes Compere and Aphytis melinus DeBach were established
after introduction in 1962 and they sufficiently controlled L. beckii and
Chrysomphalus dictyospermi Morgan (Hemiptera: Diaspididae) respectively,
which were major pests of citrus in the past (Katsoyannos, 1996a).
The parasitoid Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae) was
released in Crete twice (in 1975 and 1981) for the control of the citrus mealybug
P. citri but failed to get established (Katsoyannos, 1996a). Moreover, three
coccinellid predators were introduced, Nephus reunioni (1977), Nephus sidi (1992)
and Cryptolaemus montrouzieri Mulsant (several attempts: 1933, 1964, 1965,
1969, 1977). Establishment of the Nephus spp. was not reported, however, C.
montrouzieri Mulsant, which was the most effective of the three species, could not
overwinter in most regions (Katsoyannos, 1996a).
Four parasitoid species, Metaphycus helvolus Compere, M. bartletti Annecke &
Mynhardt, M. swirskii Annecke & Mynhardt (Hymenoptera: Encyrtidae) and
Diversinervus elegans Silvestri (Hymenoptera: Encyrtidae) targeted the control of
Saissetia oleae with relatively sufficient results (Argyriou, 1986). The coccinellid
predator Rhyzobius forestieri (Mulsant) was released 25 years ago on the island of
Chios and it is now the most abundant coccinellid found in citrus orchards. The