Impact of emamectin benzoate on nucleopolyhedrosis virus infectivity of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Alexandra A El-Helaly,Helmy M El-Bendary,Waheed A A Sayed

doi:10.1186/s41938-020-00314-0

Alexandra A El-Helaly, Helmy M El-Bendary + Show 1 more

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https://doi.org/10.1186/s41938-020-00314-0

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Abstract

BackgroundAttempts based on increasing the efficacy of Baculovirus and/or reducing the application concentration of synthetic insecticides through integrated lepidopteran management are appreciated role for conserving the environment. Impact of the multiple nucleopolyhedrosis virus (SpliMNPV) with emamectin benzoate (Em) against the cotton leaf worm, Spodoptera littoralis, was examined to identify the effective strategy for applying both agents in the control program successfully.Main bodyThe LC50 and LC90 were drastically decreased from 1.9 × 106 and 1.0 × 1010 PIB/ml in SpliMNPV treatment to reach 8.87 × 101 and 1 × 104 PIB/ml, respectively in the SpliMNPV concentrations + Em LC25 treatment. This interaction was considered as potentiation. Larvicidal activity of Em was highly increased by Em concentrations + SpliMNPV LC25 treatment than the separately Em treatment; however, this interaction was considered as additive. Moreover, the mixture treatment (SpliMNPV LC99 + Em LC50) provided almost full protection of viral pathogenicity up to 48 h at natural exposure periods. Furthermore, the mixture treatment had a negative impact on the insect survival and reproduction of treated individuals.ConclusionResults indicated that the virus infectivity was increased by a mixture treatment of SpliMNPV + Em in particular facing UV sunlight, which causes virus degradation as well as reduced the effective doses of Em. These findings suggest that this simultaneous treatment maybe an effective technique to be applied in S. littoralis control strategy.

Highlights

Attempts based on increasing the efficacy of Baculovirus and/or reducing the application concentration of synthetic insecticides through integrated lepidopteran management are appreciated role for conserving the environment
The results indicated that the larvae of S. littoralis was highly sensitive to emamectin benzoate (Em) in comparison to those stated by Bengochea et al (2014) on S
The data of SpliNPV pathogenicity is illustrated in Fig. 2; the concentrations of 1.9 × 106 and 1.0 × 1010 Polyhedral inclusion bodies (PIB)/ml of SpliNPV were reported in Median lethal concentration or lethal concentration 50 (LC50) and LC90, respectively

Summary

Introduction

Attempts based on increasing the efficacy of Baculovirus and/or reducing the application concentration of synthetic insecticides through integrated lepidopteran management are appreciated role for conserving the environment. Impact of the multiple nucleopolyhedrosis virus (SpliMNPV) with emamectin benzoate (Em) against the cotton leaf worm, Spodoptera littoralis, was examined to identify the effective strategy for applying both agents in the control program successfully. Main body: The LC50 and LC90 were drastically decreased from 1.9 × 106 and 1.0 × 1010 PIB/ml in SpliMNPV treatment to reach 8.87 × 101 and 1 × 104 PIB/ml, respectively in the SpliMNPV concentrations + Em LC25 treatment The use of insecticides to control the cotton leaf worm, Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae), and other lepidopteran pests has an adverse impact on the ecosystem and its fauna, devastation of natural enemies, and development of insect resistance (Ahmad et al 2009). Its extensive use and lethal doses applied may have deleterious effect on biodiversity

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