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

PREDATORY MITES IN IPM
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effect was additive, multiplicative or detrimental in the action of predators. The notoverlapping
degree of specialization, narrow in P. persimilis, wider in N.
californicus, and the consequent asymmetry in the response guaranteed, for some
weeks, fast (mainly due to P. persimilis) and longer (mainly due to N. californicus)
term equilibrium of the prey-predator system and of biological control, especially on
eggplant and pepper.
As concerns the ascertained intrinsic traits and versatility of some phytoseiid, N.
californicus appears able to adapt to different food and climatic conditions
(Castagnoli & Simoni, 2004), and it may be considered feasible and convenient if
combined to or in light shifts of phytoseiid releases, or in application with some
other kind of biocontrol agents (i.e. other mites, insects or the fungus Beauveria
bassiana). Obviously, the adoption of such a tactic needs an intensive monitoring, a
full evaluation of the possible effect of the microrganism on the predator and an
assessment concerning the possibility that the phytoseiid is able to recognize the
treated substrate (Simoni, Guidi, & Tarchi, 2009).
3.5. Cannibalism and Intraguild Predation
The coexistence and interaction of two different phytoseiids species sharing a
common prey resource can undoubtedly determine new functional-trophic relations
(Rudolf, 2008). Intraguild predation and cannibalism are, in cases of combined
release of predators, variables to be included in current models aiming at
overcoming the discrepancy between theory and empirical data.
Although cannibalism may often represent a weak, unuseful interaction in
nature, it may have significant consequences at the population level (McCann,
Hastings, & Huxel, 1998). Cannibalism can be a crucial factor contributing to
population structure, dynamics and control in a given habitat (McCann et al., 1998),
affecting the quantity and quality of food for the remaining individuals. Predatorpredator
interactions such as competition, intraguild predation (IGP), and
cannibalism affect the development and coexistence of predator populations, and
can have significance in the biological control of commonly exploited pest
organisms (Castagnoli, Liguori, & Simoni, 2002; Schausberger & Croft, 2000).
Furthermore, phytoseiids are suitable models for studying cannibalism and related
phenomena, due to their diversity and variability, small size and ease of rearing in
the laboratory. In future research and in the frame of tactics and strategies of control,
most fields are to be exploited, i.e. kin the link of cannibalism with discrimination
and disease transmission, the interplay between cannibalism and dispersal, and the
effects of cannibalism on population dynamics and species communities.
4. CONCLUSIONS
Given the number and complexity of factors involved in the wide pattern of natural
enemies and antagonists, phytoseiid mites appear able to significantly interact in the
dynamic equilibria of different prey-crop contexts. The modality of agricultural
pests control by these predators can range from classical biological control, with
introduction and establishment of foreign species, to safeguard and augmentation of