Reduction of Post-Harvest Injuries Caused by Drosophila suzukii in Some Cultivars of Sweet Cherries Using a High Carbon Dioxide Level and Cold Storage

SIMPLE SUMMARY: The spotted-wing Drosophila suzukii is an invasive fruit fly that causes high levels of damage to cherry fruits, which are, economically, a very important crop in the Puglia region. This pest infests mature fruits which are close to harvest, and when additional treatments are not allowed due to residue problems. The effect of infestation is a prolonged post-harvest time and up to 100% crop loss according to our field monitoring. The objective of our study was to find an effective post-harvest management of such infestations. We determined the growth rate of larval D. suzukii in infested fruits which were stored at low temperatures or treated with CO(2) at low or room temperature; such post-harvest treatments were also tested in terms of the fruit quality at the end of the storage time, with respect to untreated infested fruits. When fruits were stored at low temperature in the presence of CO(2) a consistent inhibition of larval growth was observed, with no apparent decrease of fruit quality parameters. After one month of storage, the quality parameters of treated, infested fruits were similar to the quality parameters of newly harvested fruits and non-infested fruits. ABSTRACT: Efficient strategies are required in sweet cherry fruits to control the spotted wing drosophila (SWD), Drosophila suzukii, due to its adverse economic effect on farmers. Cold storage (CS) and storage with elevated carbon dioxide (CO(2)) are environmentally safe approaches for the pest control of stored fresh fruit. These strategies are effective in controlling a wide variety of insect species, without allowing toxic compounds to accumulate. The purpose of this study was to assess the effectiveness of a post-harvest application of CO(2) treatment at 50%, cold treatment at 4 °C (CT), and a combination of both (CO(2)-CT) in controlling the early stages of SWD within four cultivars of freshly harvested cherry fruit, namely “Burlat-Bigarreau”, “Giorgia”, “Ferrovia”, and “Lapins”. In addition, an evaluation of the quality attributes of the cherries (skin firmness, berry firmness, strong soluble material, and titratable acidity) was carried out at harvest and after 10 and 20 days of storage. All treatments significantly reduced the rate of emergence of SWD when compared to the control (untreated cherry at 24 °C), and 100% SWD mortality was obtained in Burlat-Bigarreau (CO(2)-CT). In addition, over the entire storage time, the quality parameters were preserved in the samples stored at 4 °C and in the samples with combined treatments in comparison with the control.