Efficacy of Transgenic Maize LD05 Against Fall Armyworm (<i>Spodoptera frugiperda</i>)

Abstract

The fall armyworm (Spodoptera frugiperda (J.E. Smith)), which invaded China in 2018, has caused severe corn yield losses and increased pesticide application frequency. Bacillus thuringiensis (Bt)-based genetically modified corn represents an environmentally friendly and effective strategy for managing S. frugiperda. The transgenic corn LD05 harbors the m2cryAb-vip3A insect-resistant fusion gene, which has demonstrated potent inhibitory effects against fall armyworm and is currently in the phase of applying for safety certification. Here, we evaluated the inhibitory efficacy of LD05 against S. frugiperda through laboratory and field experiments during 2022–2024. The LC50 and LC95 of M2CryAb-VIP3A against fall armyworm were 0.024 μg/cm2 and 0.508 μg/cm2, respectively; and the GLC50 and GLC95 were 0.142 μg cm−2 and 0.556 μg cm−2, respectively. M2CryAb-VIP3A expression of LD05 varied significantly across tissues, and remained stable between generations. Bioassays revealed significant tissue-specific differences in fall armyworm larval mortality for LD05 corn tissues, ranked as V5-stage leaves > R3-stage kernels > R1-stage silks. Field trials demonstrated that LD05 corn significantly reduced fall armyworm larval populations, leaf damage incidence, and plant damage incidence compared to non-Bt control Zheng58. Agronomic trait analysis showed no significant differences between LD05 and Zheng58. These results indicate that LD05 has a significant inhibitory effect on fall armyworm, which is an effective strategy for the comprehensive management of fall armyworm in China.

Keywords

• agronomic traits
• efficacy
• expression
• fall armyworm
• transgenic maize LD05