A pesticidal composition comprises a synergistically effective amount of a nicotinic acetylcholine receptor (nAChR) agonist compound and a pesticide selected from N-(3-chloro-1-(pyridin-3-yl)-1H-pyrazol-4-yl)-N-ethyl-3-((3,3,3-trifluoropropyl)thio)propanamide (I), N-(3-chloro-1-(pyridine-3-yl)-1H-pyrazol-4-yl)-N-ethyl-3-((3,3,3-trifluoropropyl)sulfinyl)propanamide (II), or any agriculturally acceptable salt thereof. A method of controlling pests comprises applying the pesticidal composition near a population of pests. A method of protecting a plant from infestation and attack by insects comprises contacting the plant with the synergistic pesticidal composition.一種殺蟲組成物,其包含一協同性有效量之尼古丁乙醯膽鹼受體(nAChR)同效劑化合物以及一擇自於N-(3-氯基-1-(吡啶-3-基)-1H-吡唑-4-基)-N-乙基-3-((3,3,3-三氟丙基)硫代)丙醯胺(I)、N-(3-氯基-1-(吡啶-3-基)-1H-吡唑-4-基)-N-乙基-3-((3,3,3-三氟丙基)亞磺醯基)丙醯胺(II)或其任一農業上可接受之鹽之殺蟲劑。一種控制害蟲之方法,其包含在害蟲種群附近施用該殺蟲組成物。一種保護植物免於昆蟲感染以及攻擊之方法,其包含使該植物與該協同性殺蟲組成物接觸。