Environment: ENEA identifies cherry varieties more resistant to insect ‘pests’

A study conducted by ENEA, released on World Biodiversity Day (May 22), has shown that the dry climate helps make the flesh of certain cherry varieties firmer, increasing their protection against attacks by one of their main ‘enemies’ the Asian fruit fly (Drosophila suzukii). The research developed a laboratory screening system to assess the resistance or susceptibility of different varieties to this insect. Since its arrival in Italy from China, the fruit fly has caused significant damage to cherry production, particularly in the Sabina area of Lazio, with losses in some cases exceeding 50%.

Researchers at the ENEA Agricoltura 4.0 laboratory assessed the response of different cherry varieties to the insect’s attack, using an artificial breeding system for the fruit fly ^[1]under controlled conditions. Ultimately, a susceptibility scale for the varieties was established based on damage calculated as a percentage of affected fruit, number of punctures and the development of larvae and pupae.

“By analyzing all these parameters, we were able to identify which combination of biochemical, olfactory, visual and tactile factors most strongly influences the fruit fly, thereby determining a given variety’s level of susceptibility or resistance” explained Sergio Musmeci, an entomologist at the ENEA Agriculture 4.0 Laboratory. “The variety screening” he said “revealed lower susceptibility to attack in varieties with firmer flesh: these varieties, in fact, showed a generally lower number of bites compared to others, along with a reduced larval survival rate, resulting in limited damage.”

Tests conducted by ENEA researchers across different growing seasons also revealed a significant impact of seasonal conditions: a drier climate with lower rainfall (like in 2024) allows the fruit to increase its sugar content and firmness, characteristics that together confer greater resistance. In fact, while high sugar content can lead to an increase in the number of punctures on the fruit in some varieties, it also strongly inhibits the subsequent development of the larvae, especially in fruits with very firm flesh.

“Climate trends cause increases or decreases in insect populations, both directly- through death by dehydration in drier climates- and indirectly, by modulating the degree of resistance of cherry varieties. This explains, for example, the very different outcomes of the 2024 and 2025 seasons: the first was drier, with very low levels of damage in the field, while the second was humid and rainy, with extremely high levels of infestation and fruit that was more vulnerable to attacks by the fruit fly, as we also verified in our laboratories” Musmeci continued.

The susceptibility scale of the different cultivars will provide further valuable information for the development of an integrated monitoring system in the Sabina area and in other cherry-growing regions. The system will correlate climate trends, fruit fly population dynamics in different areas, and the characteristics of cultivated varieties. This will benefit industry operators, who will not only have access to more detailed information for proper orchard management, but will also be able to make more informed decisions when selecting varieties during orchard renewal.

Unlike the common fruit fly (*Drosophila melanogaster*), *Drosophila suzukii*, which arrived in Europe and Italy from China in 2015, is capable of attacking healthy fruit that shows no signs of rot. In response to requests from producers in the Sabina area, a working group was established in 2016 to develop a new approach to managing the problem, coordinated by the ARSIAL (Regional Agency for Innovation and Development of Agriculture in Lazio). This team gave rise to the SIMODROFILA project ^[2], funded by the Lazio Region, with the scientific contribution of ENEA and CREA, which provided farmers with low-impact solutions to contain the spread of the fruit fly, promote pesticide reduction, decrease economic losses, and at the same time improve the healthand added value of the product.