Food activity of Spodoptera frugiperda on leaves of 24 hybrids of hard yellow corn from the National Agrarian University of La Molina

Abstract

Maize is one of the most widely cultivated crops in Peru due to its importance in both human and animal nutrition, and the lepidopteran of the Noctuidae family, Spodoptera frugiperda (J.E. Smith), is one of the most significant key pests with major economic impact on the crop. In the present study, two Petri dish assays were conducted at the Entomology Laboratory of the Universidad Nacional Agraria La Molina (UNALM), from January 6 to 19, and from February 20 to March 1, 2025, respectively, to evaluate the feeding affinity of S.  frugiperda for 22 promising hybrids from the Maize Research and Social Outreach Program (PIPS) at UNALM, along with two commercial checks. A significant difference was found in the tolerance to S. frugiperda attack, expressed as the variable "Leaf Area Consumption" across larval instars, in which a progression in consumption was observed as the larvae advanced through their instars. Statistical differences were found between instars L3, L4, and L5, which exhibited the highest leaf area consumption, compared to instars L1 and L2, where no statistical differences were observed between them. Among the hybrids evaluated at 24.4 °C and 27.2 °C, more tolerant and more susceptible groups to S. frugiperda attack were statistically identified, leading to the conclusion that there are hybrids useful for genetic improvement within the PIPS Maize Program at UNALM.