Recent trends in maize entomology: Integrating host plant resistance, molecular tools for sustainable pest management

Abstract

Maize (Zea mays L.) is a globally significant cereal crop, yet its production is severely constrained by lepidopteran pests, particularly stem borers (Chilo partellus, Ostrinia nubilalis, Diatraea spp.), fall armyworm (Spodoptera frugiperda), and corn earworm (Helicoverpa zea). This review synthesizes recent advances in maize entomology, with a primary focus on host plant resistance mechanisms and their integration into sustainable pest management. Key constitutive resistance mechanisms include antibiosis mediated by biochemical factors such as DIMBOA and maysin, antixenosis through morphological traits like trichome density and husk tightness, and tolerance via plant vigor and root regrowth. The development of multiple borerresistant (MBR) germplasm at CIMMYT, coupled with marker-assisted selection (MAS) using RFLPs and QTL mapping, has significantly accelerated resistance breeding. Recent breakthroughs include the elucidation of the Cry1Ab dual-pathway mechanism against the Asian corn borer and meta-QTL analyses that have identified stable genomic regions governing insect resistance across diverse genetic backgrounds. Transgenic Bt maize expressing Cry proteins provides effective, season-long control of target pests, but its durability necessitates integrated resistance management strategies. This review underscores the critical role of conventional breeding, biochemical profiling, molecular genetics, and biotechnology in developing durable insect resistance, and advocates for integrated, multi-disciplinary approaches to ensure sustainable maize production.