Assessment of the Toxicity of Natural Oils from Mentha piperita, Pinus roxburghii, and Rosa spp. Against Three Stored Product Insects

Marwa I Mackled,May Bin-Jumah,Ahmed A Allam,Mervat El-Hefny,Trandil F Wahba

doi:10.3390/pr7110861

Abstract

Three natural oils extracted from Mentha piperita, Pinus roxburghii, and Rosa spp. were assessed in order to determine their insecticidal activity against the adults of three stored product insects: the rice weevil (Sitophilus oryzae L.), the lesser grain borer (Rhyzopertha dominica, Fabricius), and the red flour beetle (Tribolium castaneum, Herbst.). By Gas chromatography–mass spectrometry (GC/MS) analysis, the main compounds in the n-hexane oil from Rosa spp. were determined to be methyl eugenol (52.17%), phenylethyl alcohol (29.92%), diphenyl ether (7.75%), and geraniol (5.72%); in the essential oil from M. piperita, they were menthone (20.18%), 1,8-cineole (15.48%), menthyl acetate (13.13%), caryophyllene (4.82%), β-pinene (4.37%), and D-limonene (2.81%); and from the foliage of P. roxburghii, they were longifolene (19.52%), caryophyllene (9.45%), Δ-3-carene (7.01%), α-terpineol (6.75%), and γ-elemene (3.88%). S. oryzae and R. dominica were reared using sterilized wheat grains, and T. castaneum was reared on wheat flour mixed with yeast (10:1, w/w), all under laboratory conditions (27 ± 1 °C and 65% ± 5% Relative humidity (R.H). Two toxicity bioassays were used, as well as contact using thin film residues and fumigation bioassays. The results indicated that M. piperita caused a high toxicity for S. oryzae compared to other insects. High significant variations were observed between the tested M. piperita doses against the stored insects, and this natural material could be used to control insects that infect the grains. Also, the data indicated that the Rosa spp. oil had a low-toxicity effect against these insects compared to other oils. We recommend using natural oils against the stored weevils and petals, rather than the chemical agent, so as to serve human health.

Highlights

The post-harvest losses of stored cereals range from 10%–20% of the overall yearly production and are caused by insect damage, microbial deterioration, and other factors [1]
The results indicated that M. piperita was highly toxic to S. oryzae compared to the other insects
The present study showed that the M. piperita oil has potential insecticidal activity against S. oryzae, R. dominica, and T. castaneum

Summary

Introduction

The post-harvest losses of stored cereals range from 10%–20% of the overall yearly production and are caused by insect damage, microbial deterioration, and other factors [1]. (Coleoptera: Curculionidae) and the lesser grain borer R. dominica (Coleoptera: Bostrichidae) are major insects of stored grains, with both the adults and larvae feeding on whole grains. They attack wheat, corn, sorghum barley, dried beans, and cereal. They cause weight loss in grains, and they affect the quality of grains and stored products worldwide [3]. The red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), is a secondary pest of stored foods [4] It feeds on broken grain, cereals, milled grain products, dried pet food, chocolate, nuts, and cereals previously infected with insects, and they cause serious economic losses [5]

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