Can Telenomus remus and Trichogramma foersteri be used in combination against the fall armyworm, Spodoptera frugiperda?

The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), poses a global threat to agriculture, causing significant economic losses in numerous cash crops. Various control methods, including chemical insecticides, have proven insufficient against S. frugiperda, leading to a demand for alternative strategies, such as biological control. In this context, laboratory experiments were conducted to evaluate the parasitism of Trichogramma foersteri (Hymenoptera: Trichogrammatidae) and Telenomus remus (Hymenoptera: Scelionidae) on egg masses of S. frugiperda with one and two layers. Additionally, the potential synergistic use of both species against the fall armyworm were assessed. Although both species parasitized single and double-layered egg masses of S. frugiperda, Te. remus showed higher parasitism compared to T. foersteri. The parasitism of Te. remus was not affected by the competition with T. foersteri. Conversely, an increase in parasitism of T. foersteri was observed due to competition with Te. remus, especially when both species had simultaneous access to S. frugiperda egg masses. The total number of parasitized eggs was significantly higher when Te. remus was allowed to parasitize first, and when both parasitoids had simultaneous access to the egg masses. These results are crucial for the development of biological control programs using T. foersteri and Te. remus, as they indicate that both parasitoids could be used, either individually or in combination, against S. frugiperda.