Oviposition Preferences and Damage Intensity of Several Corn (Zea mays) Genotypes Against Spodoptera frugiperda J.E. Smith

Abstract

Spodoptera frugiperda is now widely distributed and has become a serious constraint to maize production in Asia and other regions. This pest has adverse effects on maize growth and yield, causing significant economic losses. Evaluating the responses and defense mechanisms of corn to S. frugiperda is essential. This study evaluated oviposition preference, leaf damage intensity, and trichome traits among 11 maize genotypes and one commercial hybrid used as a control. Oviposition preference was assessed under choice-test conditions by recording the number of egg clusters, total eggs, and egg-laying position on each genotype. Damage intensity was evaluated after artificial infestation with second-instar larvae, whereas trichome density and trichome length were measured microscopically. The fewest egg clusters were observed on the PG2 genotype (540 eggs), with most eggs positioned on the underside (abaxially) of the leaves. The lowest average damage intensity over four observations occurred in the PG7 genotype (32.27%), whereas the highest average trichome density was observed in the PG2 genotype (17.00/10mm²), and the longest average trichome length was observed in the PG7 genotype treatment (1.01 mm). Among all treatments, the PG7 genotype was the most resistant, showing lower damage intensity than the others. Identifying more resistant genotypes will help develop superior corn varieties that are resistant to S. frugiperda attacks and support sustainable agriculture. Keywords: Spodoptera frugiperda, corn resistance, oviposition preference, trichome, damage intensity.