A Pesticide Residues Insight on Honeybees, Bumblebees and Olive Oil after Pesticidal Applications against the Olive Fruit Fly Bactrocera oleae (Diptera: Tephritidae)

Olive cultivation is extensive throughout the Mediterranean region and essential for the rural economy, local heritage and the environment. To control the olive fruit fly, a major threat for this cultivation, pesticides, in the form of bait or cover sprays, are applied. These pesticide applications can potentially impact pollinators that forage in the nearby areas or live inside the olive orchards. Based on current practice, olive trees supply shadow, water, and still support some flowering plants at the period of the year with the highest temperature and minimum nectar and pollen flow, which can be beneficial for bees. In this study pesticide residues were monitored in honeybees, bumblebees, honey and olive oil, after placement of bee colonies in Greek olive orchards where applications to control the olive fruit fly took place. Variations of concentrations were evidenced, for the three active ingredients that were applied. In limited cases, concentrations in bees higher than the median lethal dose can possibly be attributed to bait dose rates or broad foraging of bees in nearby orchards with similar applications. Determined olive oil residues corroborated that those pesticides were applied in the olive orchards.