Biological Control of Insect Pests: Southeast Asian Prospects - EcoPort

4.15 Planococcus citri 305
When the ant Anoplolepis custodiens was excluded from guava trees
bearing P. citri at Nelspruit, the population of both ants and mealybugs
dropped to half. Without ants, the mealybugs were heavily preyed upon by
the ant-intolerant Exochomus flavipes and the ant-tolerant Scymnus spp.
Later, the mealybugs were almost eliminated by the fungus Cladosporium
sp. nr oxysporum (Samways 1983).
SPAIN
P. citri is parasitised by two indigenous encyrtids, Leptomastidea abnormis
and Anagyrus bohemani, but at a low level (Carrero 1980a). Cryptolaemus
montrouzieri was introduced and established before 1928 and produces
control in the warmer months (Gomez 1951; Carrero 1980b). Leptomastix
dactylopii was introduced in 1948 from California (Gomez 1951) and in
1977 from Italy, but did not become established (Carrero 1980b).
USA (OTHER THAN CALIFORNIA)
Florida
Cryptolaemus montrouzieri was introduced to Florida in 1930 for the control
of P. citri on citrus and bulbs. It became established but failed to overwinter
in sufficient numbers to achieve adequate control (Bartlett 1978; Muma
1954, Watson 1932).
Hawaii
P. citri (originally misidentified as P. kraunhiae) was the target of many
introductions (Swezey 1931), although not as severe a pest as on the
mainland. Cryptolaemus montrouzieri was introduced from Australia in
1894, Leptomastidea abnormis from California in 1915 and Leptomastix
dactylopii also from California in 1946. All became established.
Texas
In 1970, Coccidoxenoides peregrinus was the dominant parasitoid of 3
present on P. citri attacking grapefruit and Sympherobius barberi the
commonest predator (Dean et al. 1971). In 1977 Leptomastix dactylopii,
which had been introduced from California in 1970, and Anagyrus sp. nr
sawadai were found for the first time on P. citri in Texas. L. dactylopii was
the most abundant parasite in mid-August (parasitising 20.7% of P. citri),
the reputedly indigenous Coccidoxenoides peregrinus (with 48.5%) the
most abundant in late August, whereas Anagyrus sp. (with 4.3%) was the
only parasitoid recovered in mid-September. A hyperparasitoid
Prochiloneurus dactylopii attacked 1% of the primary parasitoids in mid-
August (Meyerdirk et al. 1978). Release of 5 encyrtid parasitoids on
glasshouse citrus resulted in the rapid suppression of P. citri. Leptomastidea
abnormis, Anagyrus pseudococci and Leptomastix dactylopii persisted for
periods between 24 and 32 weeks and maintained the host at low densities,
whereas Chrysoplatycerus splendens and Coccidoxenoides peregrinus