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

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R. CAMPOS-HERRERA ET AL.
chemicals within integrated pest management (IPM) programs. IPM typically
reduces pesticide use by monitoring both pest and beneficial organisms, and
predicting crop loss as the basis for management decisions (Timmer & Duncan,
1999). Nevertheless, the quantities of synthetic pesticides used in orchards remain
significant and pose serious threats to the environment, especially natural biological
control processes, wildlife, groundwater contamination, resource depletion, and
human health and safety (Edwards, 1993; Pimentell et al., 1993). Recognition of
these concerns has led to increased interest in organic methods for crop and pest
management in citriculture; and biological control, whether conducted as classical,
augmentation or conservation biological control, necessarily plays a pivotal role.
When considering the costs and benefits of various management paradigms, it is
noteworthy that increased chemical inputs do not necessarily result in increased
output per unit area. In the Mediterranean Basin, Spanish and Italian citrus growers
use 4-fold and 15-fold greater quantities of pesticides than do Greek growers, but
obtain similar citrus production per hectare (Gutiérrez et al., 2005). Nevertheless,
pest management is of frequent and critical concern in all agricultural endeavours,
and the development of sustainable pest management systems requires a
fundamental understanding of how populations of pests and their natural enemies
behave in specific crop habitats (Hoy & Herzog, 1985; Flint & Dreistadt, 1998;
Rechcigl & Rechcigl, 2000; Horowitz & Ishaaya, 2004).
In Florida citrus orchards, pesticide use during the last quarter of the twentieth
century decreased steadily as a succession of pests were shown to be manageable
through biological control by endemic or introduced natural enemies. Growers
learned that fruit destined for juice processing could usually be produced without the
use of insecticides and that fruit grown for the fresh market often required no more
than a few well-timed pesticide treatments to manage mites and fungi that cause rind
blemishes. Copper sprays and petroleum oils were the primary pesticides used
during this period, and serious outbreaks of scale and other soft body pests were rare
and almost always associated with disruption of biological control through
unnecessary use of pesticides.
Unfortunately, the limited use of pesticides and widespread success of
biological control in Florida citrus groves came to an abrupt halt when the
devastating bacterial disease known as “Huanglongbing” or “citrus greening” caused
by the bacterium Candidatus Liberibacter asiaticus, was detected in the state for the
first time in 2005. Citrus greening is vectored by the Asian Citrus Psyllid,
Diaphorina citri, infects all known citrus cultivars, spreads rapidly, and is lethal to
trees. Growers attempt to slow the spread of the disease by removing infected trees
and suppressing the vector with frequent applications of systemic and topical
insecticides. Consequently and predictably, many secondary pests are increasing in
Florida citrus orchards, and psyllid resistance to most classes of insecticides is
becoming widespread. Moreover, the increased production costs and diminishing
effectiveness of these intensive pest management practices are coinciding with lower
citrus prices, largely due to the increased availability of other fruit juices, to
significantly lower the profitability of Florida citriculture. In view of this crisis, the
future of the Florida citrus industry is uncertain. However, fundamental research to
understand and control citrus greening is being heavily supported by federal, state