Ricerche sull'entomofauna di risaia in aree risicole del nord Italia

[Autom. eng. transl.] As part of a broader research aimed at highlighting the secondary effects of some agronomic and phytosanitary practices on the composition and numerical consistency of the fauna of invertebrate rice, over 80,000 insects have been identified, generally up to the family level collected with mowing net on rice plants. The collections took place in 2013 in plots of three rice farms located respectively in Terdobbiate (Novara), Pertengo (Vercelli) and Chignolo Po (Pavia). Overall, the samplings, standardized with regard to timing and other methods, were carried out from the second half of June (post-emergency / beginning of submersion) to the first half of October (pre-collection). In order to increase the knowledge on the ecology of rice fields in northern Italy, it seemed of interest to provide a summary picture of the overall qualitative and quantitative results arising from the census of entomofauna in the aforementioned plots. From the complex of data emerged both - mainly - aspects common to the rice areas of the three provinces, and some peculiarities typical of the single districts, however without evident correlations with the agronomic and phytosanitary practices implemented. The order of insects most represented, as the number of families and also of individuals, is that of the Diptera, followed at a distance by Rincoti and Coleoptera. As expected, among the Dipterans families are biologically linked to wet places and to water (although with heterogeneous dietary regimes): Culicides and Chironomids among the Nematocera; Straziomiidi, Sciomizidi, Sepsidi and Efidridi among the Brachiceri. Out of the Culicidae is the extreme abundance in Chignolo Po: here the number of adult mosquitoes (Culex) sampled has reached almost 60,000 units in the inspection of the first ten days of July, demonstrating a synchronous and massive flicker in rice fields. The phenomenon was not observed in the other two provinces. The Chironomids, present throughout the entire seasonal arc, are more or less markedly abundant in samples from the Novara and Vercelli areas. The close biological link between the Rincoti, mostly phytomitic and sometimes potential vectors of phytopathogenic microorganisms, and the rice plant is validated for more families and species by the discovery also of juvenile forms. Very abundant in the Vercelli (especially in July), fairly in the Novarese and little in the Pavese, are the Aphidoid (Rhopalosyphum); also numerous specimens of leafhoppers (Archeorrinchi and Clipeorrinchi), in particular Delfacidi (Laodelphax) and Cicadellidi (Zyginidia, Macrosteles). Among the Heteroptera we note Miridi fitomizi (Trigonotylus) and rare Antocoridi and Nabidi, zoomizi. The Coleoptera, much less numerous, include predatory entities (Carabidae, Staphylinids, adults and Coccinellid larvae) and other phytophagous plants, represented by Chrysomelids Alticines but above all by Curculionids (mainly from the alloctonous Lissorhoptrus oryzophilus, collected in all three provinces). Hymenoptera are also modestly represented: the Parasitoid or hyperparasitoid terebres (Icneumonidae, Braconidae Aphids, Cinipoid, Calcidoid) are present in limited numbers, occasionally Aculeate Formicides (especially winged forms). The presence, however, of abundant Efemerodei and Odonati (Zygoptera and Anisoptera), two biologically linked development orders to water bodies, is widely predictable. Extremely sporadic Collembola and Tisanotteri were sampled.