Limitations to the use of Apis mellifera (Hymenoptera: Apidae) for driven pollination of cultivars: a case study with European pear (Pyrus communis L. cv. Rocha)

Abstract

The existence of pollinators able to promote xenogamy is a decisive factor in the yield of orchards. As it is allogamous, due to gametophytic self-incompatibility, most European pear cultivars do not produce fruits with seeds in the absence of pollinating insects. Therefore, the correct management and quality of Apis mellifera hives installed in the orchards are indispensable to ensure economically viable yields. In this context, we aimed to evaluate some aspects of the driven pollination system with A. mellifera that can decisively interfere with pollination effectiveness in a commercial orchard of European pear under the ecological conditions of Santa Catarina’s Mountain Plateau, in Brazil’s South region. We observed low visitation of bees on the pear flowers, possibly due to two factors: floral competition and insufficient density of hives installed in the orchard. No pollen deposition was observed on the stigmas, something which confirms pollination failure in the area. The quality of rented hives showed differences between years, with presence of the mite Varroa destructor and the microsporidian Nosema ceranae, which may have contributed to the depopulation of hives within the flowering period and, consequently, the decreased pollen deposition on the stigmas of flowers of the main fruit-producing cultivar.