Biological Control of Insect Pests: Southeast Asian Prospects - EcoPort

304 Biological Control of Insect Pests: Southeast Asian Prospects
ITALY
Infestations of P. citri develop on citrus in Sicily, Procida, Sardinia and parts
of mainland Italy, especially where it is protected by ants from its native
parasitoids, Leptomastidea abnormis and Anagyrus pseudococci (Zinna
1960). Cryptolaemus montrouzieri has been imported a number of times
since 1908 and has become established in some warmer areas, but is so
reduced in numbers during winter that satisfactory control is not obtained
without supplementations (Constantino 1935; Liotta 1965; Liotta and Mineo
1965). Coccidoxenoides peregrinus and Leptomastix dactylopii were
introduced to Procida in 1956Ð57, but did not survive the winter (Bartlett
1978). L. dactylopii was reintroduced in 1974 to this island, to the mainland
(Campania, Calabria), and to Sardinia and Sicily. At almost all 15 release
sites it afforded, initially, a high level of parasitisation (Viggiani 1975a,b).
Small overwintering populations, reduced further by hyperparasitoids and
fungus diseases, persisted in some areas, but required supplementation for
control (Mineo and Viggiani 1975a,b). L. dactylopii was again released in
1979 on Sicily and gave good results (5% of fruit infested), but it is unclear
whether or not it is able to overwinter (Barbagallo et al. 1982; Longo and
Benfatto 1982). Release of L. dactylopii in a mainland orange orchard in
Calabria led to a reduction in infested fruit from 80.9% to 12% and only
7.3% of the fruit was unmarketable (Luppino 1979). It now seems that
L. dactylopii and Cryptolaemus montrouzieri are mass reared and released
each year against P. citri (Raciti et al. 1995).
Insecticides are seldom required against P. citri in Sardinia, where
L. dactylopii may cause 96% cumulative parasitisation and where
Cryptolaemus montrouzieri and Nephus (= Scymnus) reunioni may increase
to more than 100 individuals per tree (Ortu 1982; Ortu and Prota 1983).
PAPUA NEW GUINEA
Mealybugs, including P. citri, were causing up to 75% reduction of coffee
yield in the highlands near Wau in the mid fifties. Introduction of
Cryptolaemus affinis in 1957 from the lower Markham Valley resulted in its
rapid spread and a substantial reduction of the infestations within one season
(Szent-Ivany 1963).
PERU
Very good control of P. citri is given in some areas by the encyrtid
Coccidoxenoides peregrinus, which is restricted to the citrus mealybug and
appears to have arrived accidentally in 1963 (Salazar 1972).
SOUTH AFRICA
The history of introductions to South Africa against P. citri is confused
because of misidentifications of other mealybugs for this species. However,
Bedford (1976) reports that P. citri is under biological control.