Insect resistant and glyphosate tolerant maize, Bt11 × MIR162 × GA21, can enhance management of fall armyworm and weeds in tropical Asia

Insect pests and weeds significantly hinder maize production in tropical areas of Asia, with the invasive fall armyworm, Spodoptera frugiperda (J.E. Smith), exacerbating the challenge by causing major losses. The genetically engineered (GE) maize Bt11 × MIR162 × GA21 (or Cry1Ab + Vip3Aa), which has been an effective pest management solution in the Americas for approximately two decades, has unexplored potential in Asia. This study evaluated the efficacy of this event against fall armyworm and glyphosate’s weed control capability through laboratory and field trials in China’s tropical area, aiming to improve integrated pest management (IPM) strategies in Asia. Laboratory assays showed high effectiveness against fall armyworm neonates (> 95%) and against 3rd instars (> 90%) using Bt maize tissues. Field trials validated Bt maize protection during the vegetative and reproductive phases, markedly diminishing fall armyworm larval prevalence; efficacy ranged from 99.6% in 2021, 97.1% in 2022, and 96.2% in 2023. In addition, Bt maize prevented yield losses of 9.2% to 20.9%. The results also indicated that glyphosate and a local herbicide mix (active ingredient nicosulfuron, atrazine, and mesotrione) exhibited comparable weed control efficacy under field conditions. Thus, Bt11 × MIR162 × GA21, following 3 years of research, was found to a potent IPM tool for tropical Asia, offering substantial protection against fall armyworm, weed control and aiding in trait resistance management.