Population dynamics and specific composition of phytoseiid mites (Parasitiformes, Phytoseiidae) associated with lemon trees in three differently managed orchards in eastern Sicily.

Surveys of phytoseiid mites were carried out in three lemon orchards in Sicily. The three orchards had different farm management and different environmental conditions: A) traditionally farm managed; B) organic farm managed; C) in state of neglect. The aim was to determine the specific composition of the above different types of orchards and to compare their population dynamics in order to obtain information on the influence of the different agricultural practices on the phytoseiid fauna. After two years of weekly samplings it can be assessed that no substancial differences were found in the phytoseiid specific composition among the three types of orchards. On the other hand, differences, sometimes remarkable ones, were found as far as concerns the role of the various species in the three orchards and in the various seasons. Iphiseius degenerans Berlese, Amblyseius andersoni (Chant) and Euseius stipulatus (Athias-Henriot) were present in the three orchards, Typhlodromus cryptus Athias-Henriot was found in A and B orchards, while Cydnodromus californicus (McGregor) was found only in orchard C. In orchard A the dominant species was A. andersoni (48%), followed by I. degenerans (44%) and E. stipulatus (7%). The first and the last species were present esclusively in the winter-spring period, while I. degenerans was the only species present in summer. On the contrary, in orchard B, the dominant species was I. degenerans (69%), present in all seasons, followed by A. andersoni and E. stipulatus (16 and 14% respectively). These latter ones were found exclusively in spring. In orchard C the dominant species was E. stipulatus (58%) mainly present in the hot seasons, followed by I. degenerans (38%) and A. andersoni (3%).