The efficacy of novel diamide insecticides in Grapholita molesta suppression and their residues in peach fruits

Abstract

The oriental fruit moth [(Grapholita molesta (Busck, 1916)] represents one of the most significant and destructive pests of peaches in Serbia and worldwide. Its susceptibility to the novel diamide insecticides, cyantraniliprole and chlorantraniliprole, was assessed in this article. The dissipation dynamics and behaviour of these insecticides in the peach fruit were also determined. Field trials were carried out at two localities in the Republic of Serbia (Čerević, Mala Remeta), according to standard EPPO methods. The cyantraniliprole (100 g a. i./l, SE) and chlorantraniliprole (200 g a. i./l, SC) based products were foliar applied at rate of 0.6 and 0.2 l/ha, respectively. The efficacy of the applied products was evaluated by counting the number of fruits damaged by the G. molesta larvae. The high efficacy of cyantraniliprole (89.5-94.1%) and chlorantraniliprole (93.5-95.6%) was achieved at both localities. Right after the drying of the deposit, the concentration of cyantraniliprole in the peach fruits was at the EU maximum residue level (MRL) of 1.5 mg/kg, while the MRL level of 1 mg/kg was achieved after seven days (0.95 mg/kg) for chlorantraniliprole. The cyantraniliprole and chlorantraniliprole half-life dissipation in the peach fruit were 2.50 and 3.15 days. It can be concluded that the high efficacy of the researched insecticides is a good indicator of G. molesta susceptibility in peach orchards.