Translocation of emamectin benzoate residues in the trunk, leaves, and fruits of date palm, Phoenix dactylifera

The red palm weevil, Rhynchophorus ferrugineus (Olivier), severely attacks date palm trees and has become a global problem. Due to extreme infestation of R. ferrugineus, date farmers use chemical insecticides, which are toxic to humans and animals if residues are present in fruits. In this study, we assessed residues of emamectin benzoate (Aretor®), a biorational insecticide, in the date palm, trunk, leaves, and fruits at different times (0, 3, 9, and 15 months) following trunk injection. Emamectin benzoate was injected into the palm trees using the Syngenta Tree Micro-Injection Devic. Each date palm was treated with 48 ml of insecticide solution, injected in four directions (i.e., 12 ml per direction). The concentrations of emamectin benzoate were monitored at 0, 3, 9, and 15 months for trunk and leaves samples, while fruit samples were taken at 1, 1.5, 2.5, and 3 months after treatment. The concentration of emamectin residues in treated palm trunks was 55.1 ppb immediately after treatment and 213.6 ppb after 15 months. Results indicated that the persistence of emamectin residues in the date palm trunk up to 15 months after injection can be utilized as preventive and curative endotherapy to protect date palm trees from red palm weevil infestation. Throughout the entire analysis period, the emamectin residues were not detected in the leaf or fruit samples. This research indicates that emamectin benzoate is relatively safe for humans and animals and can be a good option for red palm weevil management in date palm orchards.