Effects of five essential oils on three generalist predators and two important whitefly parasitoids

The experiment was conducted in the Entomology Laboratory of the Department of Plant Protection, Faculty of Agriculture, Bursa Uludag University in October 2020 - May 2021. The aim of the study was to determine the toxic effects of five essential oils on five important biological control agents. The commercially obtained essential oils of carrot, wintergreen, ginger, wormwood, and clove were shown to be toxic to biological control agents Orius laevigatus, Nesidiocoris tenuis, Macrolophus pygmaeus, Encarsia formosa, and Eretmocerus eremicus in three doses: 0.125, 0.25, and 0.5 v/v. After 3 hours, for the predator O. laevigatus, the most effective (100%) oils were wintergreen and clove oils, while for N. tenuis, the most effective were wintergreen (100%), wormwood (100%), and clove (97%) ones. After 24 hours, ginger oil showed a 95% mortality effect on M. pygmaeus. The parasitoids E. formosa and E. eremicus were less affected by the oils, only wormwood oil had a slightly deleterious effect on the parasitoids E. formosa and E. eremicus (mean 53% and 43%, respectively).