Beet armyworm Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) is one of the most devastating pests of different key crops. The present study deals with the toxic effect of fenvalerate insecticide on the development, reproduction and the detoxification enzyme’s activity of S. exigua feeding on tomato, cabbage, and artificial diet. The developmental period of the second instar to adult emergence was prolonged (16.74 days) reared on tomato followed by cabbage (15.97 days) and artificial diet (15.62 days). The fecundity of S. exigua was lowest on the tomato plant (279 eggs), followed by an artificial diet (347 eggs), while the highest number of eggs was observed on cabbage after the control diet (421eggs). Moreover, the lowest survival rate of the second to the third instar, fourth to the fifth instar, and hatchability were recorded in insects reared on tomato (70.89%) compared to that reared on cabbage (77.08%) and artificial diet (79.66%). S. exigua reared on tomato had the lowest intrinsic rate of increase (r: 0.133) and the highest mean generation time (T: 31.36). Furthermore, detoxifying enzyme activity in S. exigua was much lower on tomato than on cabbage and diet. Moreover, the fenvalerate toxicity was synergized by either piperonyl butoxide (PBO) or S,S,S tributylphosphorotrithioate (DEF) due to the likely participation of monooxygenases or esterase; this suggests a general metabolic resistance. This research provides a solid base for devising an applicable and successful strategy for the controlling the resistance development in beet armyworms.

甜菜夜蛾Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) 是对不同主要作物危害最大的害虫之一。本研究涉及氰戊菊酯杀虫剂对以番茄、卷心菜和人工饲料为食的甜菜的发育、繁殖和解毒酶活性的毒性作用。二龄至成虫的发育期延长（16.74 天），在番茄上饲养，其次是卷心菜（15.97 天）和人工饲料（15.62 天）。S. exigua的繁殖力番茄植株的鸡蛋数量最低（279 个鸡蛋），其次是人工饲料（347 个鸡蛋），而在对照饲料（421 个鸡蛋）之后，卷心菜的鸡蛋数量最多。此外，与在甘蓝（77.08%）和人工饲料（79.66%）上饲养的昆虫相比，在番茄上饲养的昆虫（70.89%）的第二至第三龄、第四至第五龄的成活率和孵化率最低。 . S. exigua在番茄上饲养的内在增长率最低 (r: 0.133) 和最高的平均世代时间 ( T: 31.36)。此外，甜菜中的解毒酶活性番茄比卷心菜和饮食低得多。此外，由于单加氧酶或酯酶的参与，胡椒基丁醇酯 (PBO) 或 S,S,S 三丁基三硫代磷酸酯 (DEF) 可以协同氰戊菊酯的毒性；这表明普遍的代谢抵抗。该研究为制定适用且成功的控制甜菜夜蛾抗性发展的策略提供了坚实的基础。