Larvicidal and growth inhibitory effects of endophytic Aspergillus niger on a polyphagous pest, Spodoptera litura

Abstract

Fungal endophytes that live inside plant tissues without causing any apparent symptoms in the host are known to confer resistance to insect herbivores. In the present study, endophytic fungus Aspergillus niger isolated from Acacia arabica was evaluated for its insecticidal potential against Spodoptera litura (Fab.). Ethyl acetate extract of the fungus adversely affected the survival and development of S. litura. The diet supplemented with fungal extract resulted in significantly higher larval mortality and delayed the development of the insect. Inhibitory effect of the fungal metabolites was also observed on the adult emergence, longevity, fecundity and hatchability of eggs. Ingestion of ethyl acetate extract supplemented diet by the larvae induced morphological deformities in S. litura. The adverse effects of the fungus on S. litura increased with the increase in concentration of the extract. Significant reduction in relative consumption and growth rates as well as efficiency of conversion of ingested and digested food under the influence of fungal metabolites indicate antifeedant and toxic effects of the fungus.