Efficacy of a hydroxytyrosol-rich preparation from olive mill wastewater for control of olive psyllid, Euphyllura olivina, infestations

Olive mill wastewater (OMW) is a problematic by-product in Mediterranean countries. Despite this, it is a raw material that is an unfailing source of bioactive molecules. A hydroxytyrosol-rich preparation (HRP) (49.6% weight:dry weight) was extracted from fresh OMW using a hydrolysis and post-hydrolysis purification process. The field efficacy of HRP as a spray treatment (2500 l ha−1) against olive psyllid, Euphyllura olivina (Hemiptera: Psyllidae), was evaluated in 2008 and 2009 in a drip-irrigated olive orchard.The HRP showed strong insecticidal activity against E. olivina at a concentration of 2 g l−1 hydroxytyrosol. Application of HRP resulted in 41.1 and 72.1% control of nymphs and adults, respectively. However, HRP application did not reduce egg hatch. Neither phytotoxicity nor toxicity to auxiliary-fauna was recorded with concentrations of 1.25 g l−1 or 2 g l−1 HRP. But, the 2.5 g l−1 concentration was slightly phytotoxic, especially at the E and F floral phenological stages of the grapes. HRP offers a natural and effective extract for control of olive psyllid and opens a new opportunity for the reuse of OMW.

► A high added-value molecule “hydroxytyrosol” was extracted from problematic by-product olive mill waste water. ► A hydoroxytyrosol-rich preparation was applied at a concentration of 2 g l−1 and spray volumes of 2500 l ha−1 was effective for control of olive psyllid. ► The preparation was generally safe to auxiliary fauna. ► Slight phytotoxicity was observed when the concentration reaches 2.5 g l−1. ► Two challenges in the same time, environmental and agro-economical problems, were reached.