Evaluation of Damage Parameters and Morphological Resistance Traits of Selected Maize Varieties Against Chilo partellus (Swinhoe) (Lepidoptera: Crambidae)

Abstract

The spotted stem borer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), is an invasive pest threatening maize production in Türkiye, with larvae inflicting serious damage to stems and cobs. This study evaluated four maize varieties (Hera, DS 0224, AGM 2468, and AGM 2356) under natural infestation in Hatay Province during the 2025 main-crop season, focusing on larval density, feeding damage, and the relationship with plant morphological traits. Significant varietal differences were detected across all major parameters. Hera recorded the highest larval density (2.10 larvae/plant), larvae per stem (1.46) and cob (0.64), exit holes (4.15/plant), and infestation rates in plants (59%), stems (43%), and cobs (31%). In contrast, AGM 2356 showed the lowest larval density (0.51/plant), exit holes (3.00), and infestation rates (plants 22.5%; stems 16.3%; cobs 12%), indicating relative tolerance. DS 0224 (0.79 larvae plant-1; 45% plant infestation) and AGM 2468 (1.17 larvae/plant; 50% plant infestation) exhibited intermediate susceptibility. Tunnel length did not differ significantly among varieties (6.1-7.7 cm). Correlation analysis revealed that cob height, plant height, stem diameter, leaf width, and cob length were positively associated with larval density (p < .001), whereas cob diameter showed a negative relationship. Leaf length and spike length exhibited weak negative correlations. These findings demonstrate that varietal resistance to C. partellus is strongly influenced by plant architecture. The identification of tolerant variety such as AGM 2356, alongside the recognition of morphological traits associated with susceptibility, provides a valuable foundation for breeding programs and integrated pest management (IPM) strategies to mitigate the impact of this invasive pest in Türkiye.