Influence of egg traits on parasitism by Trichogramma chilonis Ishii, 1941 and Telenomus remus Nixon, 1937 against Spodoptera frugiperda (J.E. Smith, 1797)

<i>Trichogramma chilonis</i> Ishii, 1941 and <i>Telenomus remus</i> Nixon, 1937 are the most common egg parasitoids of fall armyworm (FAW), <i>Spodoptera frugiperda</i> (J.E. Smith, 1797) in maize growing areas. FAW lays single to multilayered egg which are covered with degrees of scale thickness. Here, we assessed the parasitism of both parasitoids over different FAW egg densities (single layered), egg mass scale coverage (multilayered), and the egg ages. Two laboratory experiments were conducted from May to November 2022 under controlled conditions (24.3 ± 0.8 °C, 69.3 ± 2.2% RH). The first experiment, using a three-factor complete randomized design (CRD), involved two egg parasitoid species, single-layered eggs at three densities (20, 43, and 60 eggs), and three egg age groups (less than 12 hours, 24-36 hours, and 48-60 hours), each replicated three times. The second experiment involved two parasitoid species, multilayered eggs with three levels of egg scale coverage (fully covered, partially covered, uncovered), and three egg age groups, each replicated three times. <i>T. remus</i> exhibited significantly higher parasitism rates than <i>T. chilonis</i> in both single and multilayered egg masses. <i>T. remus</i> parasitized all egg groups uniformly, while <i>T. chilonis</i> struggled with fully covered egg masses. Parasitism percentage decreased with the age of the host eggs in both parasitoid species. <i>T. remus</i> showed a higher adult emergence percentage, regardless of egg scale covering but declined with increasing host egg age. The percentage of female progeny and development period were similar for both parasitoid species but decreased as egg density and egg age increased.