The potential of Trichogramma foersteri as a biological control agent for Spodoptera species
Egg parasitoids of the genus Trichogramma (Hymenoptera: Trichogrammatidae) are extensively used against agricultural pests in both annual and perennial crops. Spodoptera frugiperda (Lepidoptera: Noctuidae, EPPO A2 List) and Spodoptera eridania (EPPO A1 List) are polyphagous species native to the Americas. The efficacy of the newly discovered species, Trichogramma foersteri* was studied for the potential biological control of both Spodoptera species. In general, low parasitism rates are reported for Trichogramma species against Spodoptera species, in part, as female Spodoptera lay eggs in multiple layers which are protected by scales. However, screening tests performed in the laboratory have shown that T. foersteri can successfully parasitize the eggs of S. eridania and S. frugiperda. T. foersteri can negatively impact hosts without successful offspring development or direct feeding. Parasitism, non-reproductive mortality, and emergence rates of T. foersteri for both pest species were studied. T. foersteri demonstrated effective parasitism in 144 eggs (one layer) and 55 (two layers) of S. frugiperda, as well as 150 eggs of S. eridania. Non-reproductive effects also contributed to mortality in both Spodoptera species. The emergence of T. foersteri showed a high variability; on S. frugiperda it was 80 % compared to 23 % on S. eridania . The above findings highlight the potential of T. foersteri as an effective control agent for both pests.
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* Trichogramma foersteri was first described in 2021 from eggs of Anticarsia gemmatalis (Lepidoptera: Erebidae), a defoliating pest of soybean, in Paraná State, Brazil.
Sources
Sampaio F, Marchioro CA, Takahashi TA, Foerster LA (2024) A new biocontrol agent against old enemies: The potential of Trichogramma foersteri for the control of Spodoptera frugiperda and Spodoptera eridania. Biological Control 192, 105504. https://doi.org/10.1016/j.biocontrol.2024.105504