β-Cyclodextrin/eucalyptol inclusion complex for improved postharvest date moth control

The threats posed by pesticides to the environment and human health are well recognized by the scientific community. Thus, there is a need to go beyond their use and explore new alternatives. This study aims to evaluate the potential of eucalyptol, an organic natural compound found in certain plants essential oils, to control the date moth, Ectomyelois ceratoniae. However, eucalyptol is volatile and can be lost during application, so it has been encapsulated in cyclodextrins (CDs) to overcome this drawback.

Retention and formation constants of CD/eucalyptol inclusion complexes were determined. Solid inclusion complexes were then prepared in the form of powder or pellets using different (β-CD/eucalyptol) molar ratios. Release studies were performed for powder and pellets of inclusion complexes either placed in a humidity-controlled environment or immersed in water. The fumigant insecticidal activity of free and encapsulated eucalyptol was evaluated against the fifth instar larvae of Ectomyelois ceratoniae. Results showed that CD efficiently encapsulate eucalyptol in solution and in solid state with the 1:1 molar ratio showing the best encapsulation efficiency (79%) and loading capacity (135 mg/g). Under all conditions, eucalyptol was released more slowly from pellets. Higher fumigant activity, adult emergence inhibition and persistence were achieved by immersing solid powder and pellets of inclusion complex in water.

The findings showed that CD provided a controlled release of eucalyptol with improved fumigation efficacy against date moth. Encapsulation of CD therefore appears to be a valuable strategy for developing biopesticides with reduced loss through regulated release and prolonged activity. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.