peratures in southern California’s coastal val-
leys and, although it was able to survive
along the immediate southern California
coast, its numbers were often insufficient to
effect mealybug suppression (Bartlett, 1974).
With the discovery and spread of the cit-
rophilous mealybug in 1913, the citrus indus-
try was faced with a serious problem that
threatened the crop’s viability. In response to
the problem, the citrus industry promoted the
establishment of insectaries to mass-produce
the beetle (Smith and Armitage, 1920, 1931;
Quayle, 1938). The techniques for doing so
had been worked out by the early 1920s and,
for the next decade, the beetle was the princi-
pal means of suppressing this pest. In 1930, at
the height of the campaign against this pest, 16
insectaries had been established and were pro-
ducing 20 million beetles annually for release
in infested groves. Meanwhile, foreign explo-
ration for natural enemies to suppress this
pest continued. Success was finally achieved
when two parasitoids, Coccophagus gurneyi
Compere (Hymenoptera: Aphelinidae) and
Tetracneumus pretiosusTimberlake (Hymeno-
ptera: Encyrtidae), were discovered in
Australia in the late 1920s. Their introduction
suppressed the citrophilous mealybug to
subeconomic densities (Quayle, 1938) and it
remains a rare insect to this day in California’s
citrus groves.
Commercial insectaries in CaliforniaHowever, an effective and permanent biolog-
ical control agent has yet to be discovered for
one of the mealybug pests, the citrus mealy-
bug. Hence, augmentative releases are still
used in some southern California citrus
groves. During the 70 years in which this bee-
tle has been mass-reared, the rearing meth-
ods have improved and become more
efficient. Even though the number of insec-
taries producing the beetle has declined, the
number of beetles produced exceeds the 1930
levels of 20 million that were being produced
at the height of the citrophilous mealybug
campaign. In 1946, just prior to the introduc-
tion of synthetic organic pesticides in citrus
(Ebeling, 1950), seven insectaries were pro-
ducing 40 million ladybirds annually
(Flanders, 1949). By 1963, only three insec-
taries still produced this predator, but they
produced 30 million beetles annually (Fisher,
1963). Although modified and made more
efficient, the same production technique that
had been developed by Smith and Armitage
(1920, 1931) in the 1910s was still being used
in 1963 (Fisher, 1963) and it continues to be
used to this day. Adult mealybug destroyers
can still be purchased from any one of nine
suppliers (Cranshaw et al., 1996; Hunter,
1997). Thus, from its initial conceptualization
and development in the late 1910s, augmen-
tative biological control has been an integral
part of citrus pest management in California,
and it still remains so (Flanders, 1951;
DeBach and White, 1960; Fisher, 1963;
Lorbeer, 1971; Graebner et al., 1984; Morino
and Luck, 1992; Forster and Luck, 1997; Luck
et al., 1997), although the percentage of grow-
ers utilizing this tactic has waxed and waned.
The success of this pest-suppression tactic
in southern California citrus has led to the
development of commercial insectaries selling
natural enemies (Dietrick, 1981; Hunter, 1997)
or insectaries sustained by citrus protective
districts, e.g. the Fillmore Citrus Protective
District, a grower cooperative (Smith and
Armitage, 1931; Lorbeer, 1971; Graebner et al.,
1984). Historically, many of the insectaries
had also been organized by regional govern-
mental organizations within southern
California, i.e. by the County Agricultural
Commissioner, which provided the land,
supervised the building, maintained the facili-
ties and produced and distributed the natural
enemies (Smith and Armitage, 1931). The cost
of the facilities and the natural-enemy pro-
duction was borne by the citrus industry in
that county or district via an initial assess-
ment and by subsequent levies on each
grower’s annual production of citrus fruit
(Smith and Armitage, 1931). With the advent
of synthetic organic pesticides in the 1950s,
however, the county-based insectaries disap-
peared and only the private and grower-
owned insectaries remained (Graebner et al.,
1984). More recently, these grower-owned
insectaries have also become associated with
licensed pest-control advisers, who provide
grower clients with information and recom-
mendations about their pest-management
options (Lorbeer, 1971; Dietrick, 1981).Behavioural Approaches for Quality Control 233