Resistance mechanisms in collard green genotypes to : role of physical and morphological traits

Abstract

BACKGROUND: The diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), is one of the major pests of Brassica crops worldwide, causing significant economic losses. Using resistant plant genotypes is a promising strategy for integrated pest management, as it reduces reliance on chemical insecticides and helps mitigate resistance development. This study evaluated the resistance mechanisms of different collard green (Brassica oleracea var. acephala) genotypes to P. xylostella. Both antixenosis and antibiosis were investigated through oviposition preference tests and biological performance assessment. RESULTS: According to the results, there was significant variation between the genotypes. Some genotypes exhibited strong oviposition deterrence, while others affected larval survival, development time, and pupal weight. These resistance effects were associated with physical and morphological leaf traits. Genotypes 32 GUA and HS showed reduced attractiveness for oviposition and inhibited larval development and survival. These traits were linked to higher leaf wax load, increased leaf hardness, and specific leaf color parameters. CONCLUSION: hese findings indicate that resistance in collard greens to P. xylostella is mediated by a combination of physical and morphological factors, such as plant substrate color, leaf hardness, and surface wax content. Identifying and utilizing resistant genotypes can contribute to the integrated management of P. xylostella and reduce the need for chemical control measures. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.