Fungi from the body surface of Spodoptera frugiperda (Lepidoptera: Noctuidae) and bioassay of insecticidal activity

Abstract

Spodoptera frugiperda (Lepidoptera: Noctuidae) is an important insect pest in Brazil and worldwide, and its control is based mainly on chemical methods that are harmful to the environment and human and animal health. We investigated the fungal community associated with the body surface of S. frugiperda and evaluated the potential of members of this fungal community to act as biocontrol agents. The caterpillars were collected in the field, reared in the laboratory on a natural diet, evaluated for association with fungi on their surface and the environment, and subjected to a bioassay for insecticidal activity. Our results suggest that fungi are often associated with the body of S. frugiperda, as it was possible to obtain these microorganisms from all insects sampled, with a higher frequency of filamentous fungi than yeast. Fusarium verticillioides was the most frequent filamentous fungus species (F3 = 42.1%), followed by Aspergillus aureolus (F2 = 36.8%). Candida pseudointermedia was the most frequent yeast species (L1 = 57.1%). Aspergillus aureolus F2 was the only strain that exhibited toxicity against S. frugiperda and can be considered a good candidate to be explored from the perspective of obtaining biotechnological products of interest for agriculture.