Joint Action of 3 Synergists with 3 Insecticides in Spodoptera exigua (Hübner) Field Populations

Synergism of three synergists ( PBO, DEF, TPP) to cypermethrin, chlorpyrifos, methomyl were measured in Spodoptera exigua (Hübner) field populations by topical application method. Compared with DEF and TPP, PBO has higher synergism to cypermethrin. The results showed that it has higher synergism to cypermethrin with PBO at the dosage of 20 μg/larva in 0.5 h. Synergism of DEF to chlorpyrifos and methmoyl is better than that of PBO and TPP.