Acute Toxicity and Sublethal Effects of Lemongrass Essential Oil and Their Components against the Granary Weevil, Sitophilus granarius.

Angelica Plata-Rueda,Carlos Frederico Wilcken,Gabriela Da Silva Rolim,José Cola Zanuncio,Luis Carlos Martínez,José Eduardo Serrão

doi:10.3390/insects11060379

Angelica Plata-Rueda, Carlos Frederico Wilcken + Show 4 more

Open Access

https://doi.org/10.3390/insects11060379

Copy DOI

Journal: Insects	Publication Date: Jun 18, 2020
Citations: 37	License type: CC BY 4.0

Affiliation: Universidade Federal de Viçosa

Abstract

In the present work, we evaluate the toxic and repellent properties of lemongrass (Cymbopogon citratus (DC. ex Nees) Stapf.) essential oil and its components against Sitophilus granarius Linnaeus as an alternative to insecticide use. The lethal dose (LD50 and LD90), survivorship, respiration rate, and repellency on adults of S. granarius exposed to different doses of lemongrass oil and some of its components were evaluated. The chemical composition of the essential oil was found to have the major components of neral (24.6%), citral (18.7%), geranyl acetate (12.4%), geranial (12.3%), and limonene (7.55%). Lemongrass essential oil (LD50 = 4.03 µg·insect–1), citral (LD50 = 6.92 µg·insect–1), and geranyl acetate (LD50 = 3.93 µg·insect–1) were toxic to S. granarius adults. Survivorship was 99.9% in insects not exposed to lemongrass essential oil, decreasing to 57.6%, 43.1%, and 25.9% in insects exposed to LD50 of essential oil, citral, and geranyl acetate, respectively. The insects had low respiratory rates and locomotion after exposure to the essential oil, geranyl acetate, and citral. Our data show that lemongrass essential oils and their components have insecticidal and repellent activity against S. granarius and, therefore, have the potential for application in stored grain pest management schemes.

Highlights

Chemical synthetic insecticides are used to control insects in stored grain facilities
Thirteen components were found in the lemongrass essential oil, which was 96.83% of the total composition (Figure 1, Table 1)
Our results show that S. granarius exposed to lemongrass essential oil, geranyl acetate, and citral had a decrease in the respiration rates, suggesting a possible fitness cost and energy reallocation

Summary

Introduction

Chemical synthetic insecticides are used to control insects in stored grain facilities. Other alternative chemical methods to fumigants consist of protectants with long residual efficacies that target a broad spectrum of species [2] Insecticides such as pirimiphos-methyl, spinetoram, and spinosad are grain protectants and provide a rapid, lethal effect in stored product pests [3,4,5]. These insecticides cause environmental pollution [6], atmosphere ozone-depletion [7], toxic waste [8], have a long residual period of toxicity [9], and have documented insecticide resistance [1]. Among the alternative strategies to insecticides, the use of plant essential oils has been proposed for insect control in stored grains [10,11]

Methods

Results

Discussion

Conclusion