Date Received: 06-06-2026 / Date Accepted: 31-07-2026 / Date Published: 30-10-2026
The study was conducted during 2023-2025 to evaluate the resistance of the beet armyworm, Spodoptera exigua (Hübner), infesting green onion in Hanoi, Hai Phong, Hung Yen, and Bac Nninh to four commonly used insecticides Laboratory bioassays were conducted using the leaf dip method with insecticides containing chlorantraniliprole (Prevathon® 5SC), chlorfenapyr (Chlorferan 240SC), emamectin benzoate (Tasieu 5WG) and spinosad (Akasa 25SC). The results showed that S. exigua populations from all four provinces exhibited very low or low resistance to chlorfenapyr and spinosad. S. exigua population from Hai Phong exhibited high resistance to chlorantraniliprole (RR = 62.43), the Hung Yen population showed moderate to high resistance (RR = 49.56), the Hanoi population exhibited moderate resistance (RR = 25.91), whereas the Bac Ninh population showed very low resistance (RR = 9.94). For emamectin benzoate, the Hung Yen population exhibited moderate to high resistance (RR = 47.83), the Hai Phong population showed moderate resistance (RR = 41.30), while the Bac Ninh and the Hanoi populations exhibited low resistance, with resistance ratios of 13.00 and 17.47, respectively. These findings provide a basis for recommending reduced use of insecticides containing chlorantraniliprole and emamectin benzoate or their rotation with alternative insecticides, such as spinosad, to improve pest control efficacy while delaying resistance development in S. exigua populations.
