Insights into sublethal effects of Metarhizium anisopliae on the biotic potentials of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) on maize

Abstract

Background: Entomopathogenic fungi are an important biological agent in integrated pest management, playing a critical role in controlling insect populations. In the present study, the sublethal effects of the entomopathogenic fungus, Metarhizium anisopliae (Ascomycota: Hypocreales), were investigated on the biotic potential of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), which is a major pest of economically important crops. Results: Obtained results revealed that exposure to LC50 concentration of M. anisopliae resulted in a significantly longer larval developmental time (3.25–6.45 days) than the control group (2.42–5.49 days). Similarly, pupal duration was longer in the LC50 treatment (8.24 days) than in the control (6.91 days). Adult longevity was also significantly reduced in the LC50 (9.64 days) and LC30 (10.49 days) treatments compared to the control group (11.7 days). The number of eggs laid by female S. frugiperda exposed to LC50 value of M. anisopliae during the immature stages was significantly lower (464.79 eggs) than that in the control groups (696.93 eggs). Furthermore, all population and age-stage-specific parameters were significantly affected by the sublethal exposure to M. anisopliae at LC30 and LC50 values. Conclusion: These results suggest that sublethal exposure to M. anisopliae negatively impacts the life table parameters of S. frugiperda. However, the use of M. anisopliae at sublethal levels may have potential benefits for integrated pest management strategies seeking to reduce the use of chemicals.