اثر حشره‌کش تیوسیکلام و سه سینرژیست روی شب پره پشت الماسی Plutella xylostella (Lep: Plutellidae) و شب پره مینوز گوجه فرنگی Tuta absoluta (Lep: Galechiida)

The Diamondback moth Plutella xylostella L. is one of the dangerous pests of Brassicaceae and tomato leaf miner Tuta absoluta (Meyrick) is the destructive pest of Solanaceae all over the world and in Iran. Investigating the toxicity of insecticides plays an important role in select pesticides to control these pests. In this study, the insecticidal effect of thiocyclam (Eviscet ®SP 50%) was investigated alone and in combination with the synergist propenyl butoxide PBO, diethyl maleate DEM and triphenyl phosphate TPP. Thiocyclam is a nereistoxin insecticide with contact and stomach actions, which acts by blocking the synapsis of the central nervous system. Leaf dip bioassay tests were performed with third instar larvae at 25±1°c and 60±5% humidity at 16:8 L: D photoperiod. Leaf discs of canola (Zarfam cultivar) and tomato (Varamin cultivar) were used in the circle with a diameter of 3.5 cm. the experiments were tested at five concentrations with four replications with ten larvae per replication. For synergistic experiments, 200 ppm concentration from each synergist was prepared and larvae were exposed to synergists for two hours before use in the bioassay. The results were calculated using polo-plus (2006) software. The LC50 for larval stages of P. xylostella and T. absoluta was 89.15 and 212.68, respectively. Based on these results, thiocyclam insecticide is more toxic to the P. xylostella than the T. absoluta. The results of experiments with the addition of synergists (PBO, DEM, and TPP) for P. xylostella were 58.50, 49.80, and 3.58, respectively and for T. absoluta were obtained 180.15, 198.14, and 117.15. In both insects, the use of synergists (PBO, DEM, and TPP) with thiocyclam decreases LC50 and increases toxicity of that. These results indicate the role of esterase and glutathione esterase enzymes in resistance to this pesticide in both insects. Therefore, the use of a synergist with a pesticide will increase Larvicidal of them. The results of this study can be used in resistance management programs to reduce the use of these toxins.