Biological control of the invasive fruit fly Drosophila suzukii (SWD) is gaining ground in the United States through the introduction of two wasps, Ganaspis brasiliensis (known as the samba wasp) and Leptopilina japonica (known as the ronin wasp). These wasps, which evolved in Asia alongside the SWD, have been approved for rearing and managed release by entomologists to counter the spread of the fruit fly.
Entomologists at Michigan State University (MSU) initiated a project in 2023, releasing 39,000 samba wasps in 30 fruit sites in Michigan. The wasps were recovered at least in five sites, demonstrating their survival capability and successful ability to attack SWD larvae. This outcome was enthusiastically welcomed by experts as it represents the first evidence of wasps' victory in the SWD lifecycle.
Professor Rufus Isaacs from MSU emphasized the significance of this success, highlighting that samba wasps managed to surpass the lifecycle and attack SWD, marking significant progress. Dr. Andrew Jones, a graduate student of Professor Julianna Wilson, studied the samba wasps' ability to survive Michigan winters, yielding promising results.
The research and government approval process for releasing the wasps was lengthy, but evidence indicates that the wasps are up to the task. Although less than half of the wasps survived the first winter, this is considered a positive sign.
The research also involved Professor Kent Daane from the University of California, Berkeley, who contributed to identifying samba and ronin wasps as potential effective parasitoids. The wasps have been found in nature in various regions of the United States and Canada.
While some researchers express caution about the current impact on SWD populations, there is confidence that over time, the effectiveness of wasps in controlling the fruit fly will increase. Ongoing monitoring and future releases of ronin wasps could significantly reduce SWD pressure at the beginning of the season in US fruit-growing regions.
Samba wasps in a container before release
Read the full article: Good Fruit Growers
Images: Good Fruit Growers
12 Dec 2025
In the last decade, Chile turned cherries into a premium export worth over US$ 1.8 billion, driven by ideal climate, advanced technical management and booming Chinese demand. Andean areas of Peru show potential, but would require infrastructure and adapted strategies.
24 Apr 2025
The first cherries of 2025 have arrived in Uzbek supermarkets with prices between 14,990 and 19,999 SOM. Comparison with previous years, local market trends, exchange rate, domestic production and insights on global export dynamics.
10 Apr 2026
The first Spanish greenhouse cherries reach the European market with very limited volumes and prices up to €80/kg. Strong demand from the Netherlands, Scandinavia and the UK, while the open-field season may start later than usual, impacting exports.
10 Apr 2026
A study on 22 sweet cherry cultivars in Zaragoza examines how warmer winters affect dormancy and flowering. Declining winter chill alters phenology and threatens yield, varietal adaptation and long-term sustainability in Mediterranean growing regions.
