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
15 May 2024
Italy continues to lose positions in the ranking of the largest cherry producers in the world. Currently, the beautiful country is in seventh place, surpassed by Spain and chased by Greece. In just three five-year periods, national production has dropped by 15%.
12 Nov 2024
In the 2024/25 season, we are observing much higher fertility than seen from 2018 to 2023, which may lead to an abundant bloom. This is compounded by the fact that the potential size or caliber of the fruit is limited from the outset due to the increased number of flowers on the
22 May 2026
The CTIFL 2026 report presents guidelines to protect cherry trees in France from Drosophila suzukii, combining monitoring, netting, sanitation, biological control and authorized plant protection products for targeted, sustainable crop defense adapted to sites and varieties.
22 May 2026
Cherry orchard covers in Chile no longer protect only against rain: they now regulate microclimate, reduce cracking, improve export quality and fruit condition, supporting more stable economic returns in modern orchards exposed to growing climate risk and market pressure.
