Potential molluscicidal and antimicrobial activities of rare earth elements against the land snail Theba pisana and certain microorganisms

A novel application of light rare earth elements (LREEs) was explored for their biological activity as potential eco-friendly molluscicides and antimicrobials on Theba pisana (Müller, 1774) and their feeding behavior, and microorganisms like Candida albicans, Bacillus cereus, Aspergillus niger, Staphylococcus aureus, and Escherichia coli. Our data showed increased snail mortality with higher element concentrations till 500 mg/L. LC₂₅ and LC₅₀ values after ten days of exposure were 513.70 and 3012.72 mg/L, respectively, lower survival rates than the control. As treatment concentration and exposure duration increased, the ingested leaf area and daily consumption rates of treated lettuce leaves declined. On day one, consumption dropped from 60.00 ± 0.00 cm² (control) to 30.25 ± 6.13 cm² at 500 mg/L, further decreasing to 31.25 ± 0.76 cm² and 14.00 ± 1.46 cm² by day four at the same concentrations. Low concentrations had minimal impact on snail feeding, while higher levels significantly reduced appetite, consumption and freshness of leaves. LREEs-based formulations exhibited marked antimicrobial activity against all tested pathogens by the measured inhibition zones. Results highlight the promising application of LREEs in integrated pest and microbial disease management. However, these findings warrant further investigation to optimize their safe and practical use in the field.