Pollen availability and abundance of predatory phytoseiid mites on natural and secondary hedgerows

Mites occurring on natural and secondary hedgerows located in north-eastern Italy were monitored with particular attention to phytoseiids. Pollen diversity and abundance were analysed to highlight relationships between pollen availability and phytoseiids. Secondary hedgerows were structured in modules containing a single species and modules containing a mixture of species. These hedgerows were contiguous to a vineyard. Natural hedgerows were located in the same area. The pollen of Poaceae was the most important among non-arboreal pollen taxa (NAP), and that of elderberry among arboreal pollen taxa (AP). Pollen diversity was higher on natural than on secondary hedgerows. Pollen densities reached high levels in spring and decreased in summer. Pollen and phytoseiid mites were more abundant on natural than on secondary hedgerows. On elderberry and hornbeam a potential relationship between pollen availability and the abundance of phytoseiids (Euseius finlandicus) was found. Pollen applications increased the fecundity and the abundance of this species.