Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Sublethal effects of Nomuraea rileyi on development of Spodoptera frugiperda (Lepidoptera: Noctuidae).

Abstract

Nomuraea rileyi represents a promising biocontrol agent of fall armyworm Spodoptera frugiperda. Based upon a native strain Nm005, a biopesticide prototype, which produced mortality under laboratory conditions of S. frugiperda upper 90%, has been developed. Taking into account the importance of studying pathogen-insect interactions as a crucial factor for optimization of biopesticides, the objective of this study was to evaluate sublethal effects of N. rileyi Nm005 over biological parameters of S. frugiperda immature stages and adults. Nm005 was applied to eggs and second and fifth instar larvae in a lethal concentration 30 (LC30), (2.4Ă—103 conidia ml-1) to determine the effect through a generation. Larval mortality, longevity and weight of pupae were evaluated. Surviving adults were mated and the fecundity and fertility were determined. The same parameters were registered in the next generation and each developmental stage was compared with a control. Second instar larvae were the most susceptible to LC30 of N. rileyi, with 36.3% mortality, compared to treatments of eggs or fifth instar larvae, with 17.9% and 13.2%, respectively. A sublethal effect was evident in fertility of surviving adults when second instars had been treated with the fungus (50.5% fertility) in comparison when eggs and fifth larvae instar had been treated (80.6% and 83.4%, respectively). Sublethal effects were evident in adults of the second generation obtained after treatment of eggs and second instar.