Endophytic fungi from South Sumatra (Indonesia) in seed-treated corn seedlings Affecting development of the fall armyworm, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae)

Abstract

Abstract Background Topical application of the entomopathogenic fungi (EPFs) against Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) larvae is less effective due to larvae hiding in the corn midribs in the field. To control the larvae, the fungi colonize in plant tissues or endophytic fungi are needed. There is no information on the pathogenicity of the endophytic fungi from Indonesia on the development of S. frugiperda. The endophytic fungi isolated from infected-host cadavers from South Sumatra (Indonesia) were identified morphologically and molecularly, and the effect of seed-treated corn seedlings with the fungi on S. frugiperda development was evaluated. The fungal identification was based on morphological and molecular characteristics. Bioassay of the endophytic fungal species in seed-treated young maize was performed against the neonate larvae (hatching within 24 h.) of first instar, and their development was observed. Results The results of molecular identification showed that the fungal species were Beauveria bassiana of five fungal isolates (WTTJC290521B, WTTJC290521A, JGTP240521A, JGNT300521, and WTTJC260521A) and Metarhizium anisopliae of an isolate (WTTJC260521B). The life span of S. frugiperda fed on leaves of fungal-colonized maize was significantly longer than those fed on leaves of non-colonized maize. The fungal-colonized young maize significantly increased mortality rate of all larval instars than non-colonized one. The last instar larvae mortality treated with B. bassiana (JGTP240521A isolates) (51.33%) was the highest among other treatments and did not significantly differ from each of B. bassiana of WTTJC260521A and WTTJC290521A isolates 45.33% and 44.67%, respectively. Feeding on leaves of fungal-colonized maize significantly decreased the percentage of the last instar larvae development to the pupal stage, the adult emergence, the eggs laid, and the percentage of hatched eggs. This is the first report that B. bassiana and M. anisopliae from South Sumatra (Indonesia) in seed-treated corn seedlings had negative effects on development of S. frugiperda. Conclusions Finally, these results highlight the potential of endophytic EPFs to protect corn plants against S. frugiperda.