Fall armyworm (FAW) Spodoptera frugiperda is considered the main defoliating insect pest of maize in many countries. Silicon (Si) applied to plants has been shown to increase the resistance to insects, especially in grasses such as maize. This study characterized the effects of Si fertilization regarding priming, induced resistance, and tolerance to FAW in a landrace variety and hybrid of maize. Si was applied in soil of potted-plants as H 4 SiO 4 at 2 t ha − 1 when maize plants were at V2 stage, and when they reached V3 two FAW neonates were infested in the plants whorls. Plants at V4 were reinfested with a 4thinstar larva that was kept feeding until V5 stage. Concentrations of H 2 O 2 and malondialdehyde were used as proxies of injury and oxidative stress, and activities of antioxidant enzymes were related to Si-induced responses on plants growth, and FAW injury and performance. As main results, there was reduced FAW injury and larval weight gain in Si-treated plants subjected to herbivory. Greater root dry mass was observed in the landrace variety with Si and without herbivory. Landrace plants showed higher shoot weights than the hybrid under FAW infestation. Si-fertilized plants showed higher H 2 O 2 concentrations.The highest peroxidase activities occurred in Si-treated plants without herbivory, and the catalase and superoxide dismutase activities were highest in Si-treated plants without herbivory or herbivory-injured plants without Si. These results are important for characterizing the Si-induced defense effects in maize to FAW, which can bene t the strategic use of Si in integrated pest management.
Key MessageSpodoptera frugiperda is a polyphagous pest that threatens food security in many countries.Plants of maize landrace and hybrid were fertilized with Si to characterize triggered defense responses regarding induced resistance, priming, and tolerance to insect herbivory.Si effects on insect performance, plant growth, and antioxidant enzyme activities were more speci c to maize landrace and varied in conditions with and without herbivory.Si primed chemical defenses in landrace maize that were potentiated by induction of resistance following insect herbivory.