Efficacy of different insecticides in control of Spodoptera cilium in laboratory and field conditions

Spodoptera cilium Guenee is one of the pests of grasses in the landscape of the southern regions of Iran and many countries of the world. In this study, the effects of some insecticides, including, indoxacarb, fanvalerate, diflubenzuron, Imunit® (Alpha Cypermethrin +Teflubenzuron) and Bt were investigated against larvae of S. cilium in laboratory and field conditions. The laboratory bioassays were performed by leaf dipping method at 250C, 60±5% RH, and 16:8 light: dark conditions. The results indicated the LC50 values from low to high of imunit®, indoxacarb, diflubenzuron and fanvalerate, 48 h after lavae exposure were 27.7, 60, 187.8 and 1057.0 ppm, respectivley. In the second experiment, grass leaves were treated with recommended and half recommended concentration of tested insecticides using leaf dipping method. Then, the mortality of second and fourth instar larvae were counted daily up to five days. A day after exposure, the highest mortality percentage of the second instar larvae was related to the recommended concentration of indoxacarb, fenvalerate and imunit®, respectively, with 99.0±1.0, 92.0±2.3 and 89.0±1.0%, respectively. In this time, the highest mortality level of fourth instar larvae was related to the recommended concentration of imunit® and indoxacarb with the mortality of 58.0±2.0% and 56.0±5.9%, respectively. The greatest reduction in the damage percentage in the field test was reported 19 days after spraying is related to the recommended concentration of indoxacarb, and imunit® with 6.0±1.0 and 28.0±0.0%, respectively. According to our results, immunit and indoxacarb have been shown to control the population and reduce the damage of S. cilium, and can be used in this pest control programs.