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

IPM THROUGH ENTOMOPARASITES
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CONCLUSIONS
Basic and applied study of the EPN/bacteria symbiosis has increased steadily during
the past half-century, coincident with an accelerating awareness of limitations that
characterize many conventional pest management practices. An extensive literature
on the effectiveness of EPNs as biopesticides is in striking contrast to the paucity of
information about the ecology of these cryptic predators of subterranean arthropods.
Their population abundance is usually inferred from the numbers of sentinel insects
they kill but, unlike plant parasitic and free living nematodes, there are few reports
of the actual numbers of these worms in different soil habitats. Consequently, little
is known about their population biology – neither the factors that govern population
size nor the numbers of worms needed to achieve economic pest suppression in
different habitats. The great variety of species with very different life strategies
provides tremendous opportunities to study how food webs and soil conditions
affect the abundance of nematodes with different traits. Understanding the
population biology of EPNs is necessary to discover and exploit new ways to
increase their efficacy and, more importantly, their reliability for biological control
in managed ecosystems. For example, trophic cascades that result from augmenting
EPNs in citrus orchards have the potential to interfere with the effectiveness of this
IPM tactic if the non-target effect (i.e., the temporary suppression of EPNs by
natural enemies) occurs at a peak time for D. abbreviatus egg hatch and larval
recruitment into soil. Can better timing of EPN applications reduce this risk? Would
the application of EPN species less susceptible to predation by NF modulate the
trophic cascade and the potential for non-target effects? What physical
characteristics of soils are amenable to change in ways that enhance either the
numbers or the effectiveness of EPN? The ready availability of molecular tools to
identify and measure EPN and their natural enemies in the soil should facilitate
more rapid progress in our understanding of how these organisms co-exist and how
we might better manage soils to maximize their biological control potential.
ACKNOWLEDGEMENTS
The authors gratefully acknowledge postdoctoral fellowship support from the
Ramón Areces Foundation (Spain) to R. Campos-Herrera and a US-Egypt project
for IPM in citrus (contract 260) to L. W. Duncan.
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