Ecofriendly control of Drosophila suzukii via the photoinsecticide chlorophyllin

BACKGROUND

Drosophila suzukii is an invasive pest causing high losses of agricultural crops. Conventional treatment strategies are considered problematic for their high risk of inducing resistance and environmental harm. Photodynamic Inactivation (PDI) is based on the photosensitizer-mediated and light-dependent generation of reactive oxygen species. Natural and food-grade photosensitizers, such as the food additive sodium magnesium chlorophyllin (Chl, E140), have been proven effective against microbial pathogens and several agricultural pests. The aim of this study is to assess whether the principle of Chl-based PDI of D. suzukii could be transferred from laboratory towards practical conditions.

RESULTS

We prove that D. suzukii is photokilled after feeding on 5 mM Chl with 3% sucrose (98.4% median moribundity, 9 h drug to light interval, 78.9 J/cm² radiant exposure). Therefore, aspects of environmental safety and practical feasibility were assessed, using streamlined variations of the same assay: the required photosensitizer concentration could be reduced to 0.5 mM Chl (90.1% median moribundity 6 days after 315.6 J/cm² illumination with LEDs). Chl was photoactivable with sunlight (92.5% median moribundity, 6 days after 294.5 J/cm² and 1 mM Chl). Offering alternative food lures did not impair this effect. Photobleaching rendered Chl non-toxic (2.5% median moribundity after bleaching Chl with 78.9 J/cm² with subsequent illumination using 157.8 J/cm²). Furthermore, fluorescence microscopy of Chl-fed flies confirmed Chl accumulation in the flies' intestines.

CONCLUSION

Our findings demonstrate that Chl-based PDI could be harnessed as a safe and effective alternative for the management of D. suzukii pests. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.