Evaluating currently used pesticides in apple orchards on field populations of Tetranychus urticae Koch (Acari: Tetranychidae)

Abstract

Tetranychus urticae Koch, 1836, is a major pest on apple trees. In order to control this pest, the effect of spirodiclofen SC 240 with new trade name as Inventor® in two concentrations 0.5 and 0.6 mL/L of water, compared to Envidor® (spirodiclofen) 0.5 mL/L, Pride® (fenazaquin) 0.5 mL/L, Ortus® (fenpyroximate) 0.5 mL/L, Flumite® (diflovidazin) 0.5 mL/L, and control (only water) on motile forms on apple trees cv. “Golden Delicious” was investigated. A randomised complete block design was used with four replications in Tehran, Khorasan-e Razavi, and Isfahan provinces in summer 2017. A sampling of 20 leaves was used to assess the mortality rate of target pest from each experimental unit 1 day before and 3, 7, 14, and 21 days after treatment. Data obtained from sampling were corrected by Hendersonis–Tilton formula. The data were compared using Duncan test by SAS software (p < 5%). The results showed that there was a significant difference between all treatments with control in all three provinces (p < 5%). Results revealed that in Tehran and Isfahan, the highest efficiency at all times was related to both concentrations of invertor® with more than 82% mortality. In Khorasan-e Razavi province, on the third and seventh days, both concentrations of inventor® and pride® were most effective, and finally, on days 14 and 21, the concentration 0.6 of inventor® and pride® had the highest efficiencies and the concentration 0.5 of inventor® was in the next rank. Therefore, based on the results of all three locations, it can be concluded that both concentrations of Inventor were effective in controlling the T. urticae, and dose 0.5 is acceptable and can be recommended for controlling this pest, which has the mortality rate reaching over 82%.