Chahed A. et al (2020)

Abdessalem Chahed, Andrea Nesler, Ilaria Pertot, Gerardo Puopolo, Michele Perazzolli

INFORMATIVE ABSTRACT - Drosophila suzukii (see picture aside) is a pest of fresh fruits, which is heavily affecting fruit industry in Europe. It is the only Drosophilid fly with serrated ovipositor, which make fresh fruit unmarketable.

The aim of the study was to evaluate the behavioral responses of D. suzukii females to odors released by fresh and ripe berries of two varieties of table grapes (white and black ones) i.e. Vitis vinifera, var. Victoria and var. Black magic, using behavioral bioassays. The efficient olfactometer was expected to contribute in the designing of innovative concepts for plant protection technologies and development of trapping systems for integrated pest management strategies against this pest.
Firstly fruit grapes were collected from Apulia region in Italy at ripe stage and the experiments were conducted in a laboratory investigating two-choice bioassays. Each sterilized and non-sterilized variety was tested separately in the olfactometer and each choice test was replicated 10 times. Flies in both fruit were compared to control arm and treatments, specific statistical approach was used in doing so.

The study showed for the first time behavioral responses of D. suzukii to odors emitted by two varieties of table grape of agricultural importance in Italy. As result by the obtained data, the olfaction has important role in selection of grapes for feeding and oviposition, which reconfirmed that D. suzukii is capable of infesting a wide range of hosts and table grapes. In particular, white grapes variety is highly susceptible to this pest infestation in Apulia region.

However, flies attraction towards non-sterilized fruits can also be related to microorganisms associated with the fruit surface. Lastly, further studies are underway to identify microorganisms and volatiles emitted by them that elicit antennal and behavioral activity.