| Popis: |
Field surveys were conducted in 2015-2016 in a total of 50 olive orchards of Apulia region, by recording the incidence of the different plant species and the presence of Philaenus spumarius (Ps) nymphs on at least 100 plants within each genus (Cornara et al. 2017). Percentage of infested plants, number of infested plants over total infested plants within each orchard were determined and hostplant preference was estimated by Chesson’s index (Chesson J. 1978). Nymphs were recorded on plant species of ca. 70 different Genera, with the highest rates of infestation recorded on plants belonging to the Asteraceae and Fabaceae. Sonchus, besides being a very common weed in the olive orchards of the region, was one of the preferred host-plants, representing up to 22% of total infested plants. On the contrary, other common weeds, such as Papaver, Fumaria, Lamium, Oxalis, Mercurialis and Capsella, were not found infested by the nymphs of Ps. Indeed, very rarely spittles were found on plants of Cruciferae and Gramineae. In conclusion, our surveys confirmed that Ps has a very high polyphagy and capacity to adapt to very different plant communities. Nevertheless, densities of this insect showed great variability between orchards characterized by different plant communities, type of soil, environmental conditions and management. |
