Residues of rotenone, azadirachtin, pyrethrins and copper used to control Bactrocera oleae (Gmel.) in organic olives and oil

Abstract

Rotenone, azadirachtin, pyrethrins and copper fungicide decay curves were determined in olives and olive oil samples after experimental trials, consisting of one, two and three applications of each active ingredient, were carried out twice in 2005 and 2006. Rotenone, azadiracthin and pyrethrins were analyzed by extraction with acetonitrile and determined by liquid chromatography; copper was extracted into aqueous HCl and determined by chemical stripping. Pyrethrins were always found but in levels below the acceptable limits, whereas rotenone and copper residues always exceeded, after the pre-harvest interval, the maximum threshold allowed for olives. As regards residues in olive oil, rotenone was found in concentrations higher than those detected in olives. Copper accumulated in olives according to the number of applications, whereas, in oil, the residue was always lower than the maximum residue limit. The sensitivity of the method applied did not allow detection of azadirachtin.

Keywords:

• organic olive growing
• rotenone
• azadirachtin
• pyrethrins
• copper
• residues
• olives
• oil

Acknowledgements

The present work was carried out within the framework of the Interreg III A Project Italy–Albania 2000–2006 “Progetto finalizzato integrato per la diffusione e assistenza tecnica all’implementazione di metodologie per la produzione di prodotti biologici”; Acronym: (PAB). The authors thank Professor P. Cabras (Toxicology Department, Cagliari University) and Dr S. Pollastro (Plant Protection Department, Bari University) for the scientific review of this paper.