Pre-emptive biological control of Spodoptera frugiperda using Trichogramma species
The fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae - EPPO A2 List), is a highly invasive pest of maize and other crops worldwide. It has recently been reported in a few EPPO countries. Trichogramma species are egg parasitoids that are commonly used as augmentative biological control agents against a variety of pests worldwide. Some Trichogramma species have been used against S. frugiperda, for example, T. pretiosum in the Americas and T. chilonis in China. It is generally considered that full control of S. frugiperda using Trichogramma species is not easily achieved as the parasitoid cannot reach all eggs as the egg mass is composed of two or three layers and protected. In studies to assess the pre-emptive augmentative biological control of S. frugiperda, three European Trichogramma species (Trichogramma brassicae, T. dendrolimi and T. cacoeciae) were tested for their ability to parasitize egg masses with one to three layers and with or without protective covering (hair and scale cover). Each Trichogramma species was tested on egg masses with: one-layer without hair; one-layer with hair; two-layers without hair; two-layers with hair; three-layers with hair. T. dendrolimi was the most efficient species in reaching the eggs at the lowest layers with protective covering. T. cacoeciae was the least successful. Depending on the number of egg layers and presence or absence of covering, parasitism rates by T. brassicae, T. dendrolimi and T. cacoeciae varied between 99 and 41 %, 100 and 43 % and 100 and 28 %, respectively. Even though Trichogramma species may not be able to parasitise all eggs in the mass, they can be considered as biological control agents in a IPM programme and also used in combination with other natural enemies.
Sources
Kenis M, Zhong Y, Fontes J, Herz A, Babendreier D (2024) Pre‑emptive augmentative biological control of Spodoptera frugiperda in Europe using Trichogramma spp. CABI Agriculture and Bioscience 5, 96. https://doi.org/10.1186/s43170-024-00296-1