Taking a look at local parasitoids that kill Drosophila suzukii in the Southeast USA

27 Jan 2025
469

Drosophila suzukii (Matsumura) is an insect that belongs to the order Diptera, like flies and fruit flies. Despite its very small size, it can be recognized by the dark spots on its wings, which also characterize its common English name, spotted-wing drosophila (SWD). The damage it can cause is significant because, thanks to its ovipositor, it can lay eggs directly inside the fruit.

The larva will then feed on these tissues, making the affected fruits unmarketable. Considering that the life cycle of this insect is short, especially in spring, the infestation rate within the cherry orchard can become very high.

Finally, in terms of its diet, it is not selective and can survive by feeding on various types of fruits. This is why the drosophila represents a serious threat to the economic well-being of various small fruit-growing enterprises in both Europe and the Americas. To reduce the use of synthetic chemicals and thus develop a more sustainable management of Drosophila suzukii, a potential technique is the use of parasitoids for biological control.

In North America, in order to use parasitoids as biocontrol agents, it is essential to recognize and understand their presence, as well as their preferences and the ways they have adapted to their environment.

Between 2021 and 2022, researchers from the Department of Entomology at the University of Georgia conducted two field surveys to study the North American native parasitoids of Drosophila suzukii. These surveys were conducted in the main blueberry-producing regions in the southeastern United States, specifically in Georgia.

A total of 371 Drosophila parasitoids were collected through the deployment of sentinel traps consisting of fruit baits. From the results, it emerged that the parasitoids all belonged to the order Hymenoptera, specifically to three families: Figitidae, Pteromalidae, and Diapriidae.

Image 1: Pachycrepoideus vindemmiae.

Pachycrepoideus vindemmiae and Leptopilina boulardi were the most prevalent species. The abundance of parasitoids was higher during the peak ripening period of blueberries until the end of the harvest season compared to all other phenological stages. Of all the North American native Drosophila parasitoids that were collected, Pachycrepoideus vindemmiae was able to effectively parasitize Drosophila suzukii in its natural environment.

On the other hand, L. boulardi was able to parasitize Drosophila larvae in the laboratory but at a rate of 7%.

Moreover, it did not manage to emerge from all the individuals it had parasitized, showing difficulties in completing its developmental cycle. This means that even when a high presence of parasitoids is detected at certain times of the season, this number is subject to high variability with a likelihood of population decline since not all parasitoids manage to reach the adult stage. The researchers concluded that the local parasitoids already present in North America are not sufficient to successfully reduce Drosophila suzukii infestations in these areas.

It has been determined that in these regions it is necessary to implement a planned intervention that includes the classical release of specialized native Asian parasitoids, in addition to the common control measures already implemented.

Source: Subin B Neupane, Jason M Schmidt, William E Snyder, William G Hudson, Xingeng Wang, Matthew Buffington, Kent M Daane, Ashfaq A Sial, Assessing native parasitoids of the invasive pest Drosophila suzukii (Diptera: Drosophilidae) in the Southeastern USA, Environmental Entomology, Volume 53, Issue 6, December 2024, Pages 966–972, https://doi.org/10.1093/ee/nvae086.
Images: Waspweb

Melissa Venturi
University of Bologna (IT)


Cherry Times - All rights reserved

What to read next

Early cherry seminar in Ovalle (Chile) to assess future growth and quality

Quality

28 May 2024

Ovalle was once again the capital of early cherries. Organised by Susttex, the Cerezas Primores seminar brought together producers, companies, academics and people interested in cherry cultivation in the Coquimbo region for the third year running.

Cherry growers and consumers in Washington continue to focus on the Rainier variety

Varieties

27 May 2024

The Rainier price remained above $5 per pound. ‘It was the only cherry we made a profit on last year. That's what we count on every year,' said John Griggs Jr. who grows about 200 acres of cherries, half of which are Rainier.

In evidenza

Sweet cherries: German season kicks off with early harvests and limited supply

Production

25 Jun 2025

The German sweet cherry season has officially begun with early varieties such as Burlat and Bellise. Although volumes are still limited, growing interest from retailers and active promotional campaigns are boosting demand, with expectations for a dynamic European market ahead.

Silver nanoparticles to fight Drosophila suzukii in fruit cultivation

Crop protection

25 Jun 2025

Chitosan-coated silver nanoparticles (AgChNPs) show high efficacy against Drosophila suzukii, a major fruit pest. This sustainable biotechnological solution reduces adult emergence, reproduction, and causes morphological damage, offering a valid alternative to insecticides.

Tag Popolari