Ömer Cem Karakoç

Insecticidal Activity of Fatty Acid-Rich Turkish Bryophyte Extracts Against Sitophilus granarius (Coleoptera: Curculionidae)

The composition of fatty acids and insecticidal effects was performed for the Turkish mosses Dicranum scoparium, Hypnum cupressiforme, Polytrichastrum formosum, Homalothecium lutescens and the Turkish liverwort Conocephalum conicum. All structures were determined by means of gas chromatography and gas chromatography-mass spectrometry techniques. The determination of fatty acids was done using a simple and mild method that utilized different solvent extractions ranging from nonpolar to polar solvents (hexane, dichloromethane, chloroform, ethyl acetate and methanol, respectively), and the samples were powdered with and without liquid nitrogen. The correlations between the saturated and unsaturated fatty acid contents depending on the solvent polarity and their crushing process by liquid nitrogen were observed. The insecticidal activity of the bryophytes was analyzed by using the methanol, hexane and esterified methanol extracts. The hexane extracts of Polytrichastrum formosum showed the highest insecticidal activity (70.33%) against Sitophilus granarius. Contact toxicity activities of lauric, myristic and palmitic acids besides single dose studies of the solvent extracts were carried out. The highest mortality rate (53.34%) was obtained from the myristic acid among the tested pure fatty acids. The activities of palmitic and lauric acids were 17.75% and 4.32%, respectively.

Sitophilus granarius L. (Coleoptera) Toxicity and Biological Activities of the Essential Oils of Tanacetum macrophyllum (Waldst. & Kit.) Schultz Bip.

Insecticides of the natural origin are an important alternative to the synthetic insecticides that are being employed for the preserving stored products. The volatiles obtained from T. cinerariifolium (=Pyrethrum cinerariifolium) is being used for many types of insecticidal applications; however there is a very little information on the insecticidal activity of the essential oils of other Tanacetum species. The main purpose of the present study is to determine the chemical composition of T. macrophyllum (Waldst. & Kit.) Schultz Bip. essential oils and evaluate their insecticidal activity against S. granarius as well as its other beneficial biological activities. Highest contact toxicity was observed in the leaf oil of (88.93%) against S. granarius. The flower oil showed considerable fumigant toxicity against L. minor at 10 mg/mL application concentration (61.86 %) when compared with other samples at the same concentration. The highest DPPH (2,2-Diphenyl-1-picrylhydrazyl) scavenging activity (47.7%) and phosphomolybdenum reducing activity was observed also for the flower oil of T. macrophyllum at 10 mg/mL concentration. The essential oils were analyzed by GC, GC/MS. The flower and leaf oils were characterized with γ-eudesmol 21.5%, (E)-sesquilavandulol 20.3%, copaborneol 8.5% and copaborneol 14.1%, 1,8-cineole 11%, bornyl acetate 9.6%, borneol 6.3% respectively. AHC analysis of the qualitative and quantitative data obtained from the essential oil composition of the T. macrophyllum essential oil from the present research and previous reports pointed out that two different chemotypes could be proposed with current findings which are p-methyl benzyl alcohol/ cadinene and eudesmane chemotypes.

Chemical composition and insecticidal activity of edible garland (Chrysanthemum coronarium L.) essential oil against the granary pest Sitophilus granarius L. (Coleoptera)

Abstract The essential oil composition and biological activities of Chrysanthemum coronarium L. from three locations in Cyprus were investigated. A total of 35 components were identified in the oils representing 86.2 ± 0.7%–93.8 ± 0.0% (n = 3) of the oils. Camphor 25.2 ± 0.1%–9.1 ± 0.3%, santolinatriene 21.7 ± 0.1%–3.6 ± 0.1%, yomogi alcohol 12.6 ± 0.1%–3.6 ± 0.1%, cis-chrysanthenyl acetate 10.7 ± 0.1%–6.8 ± 0.1% and bornyl acetate 11.0 ± 0.5%–5.7 ± 0.0% were identified as the main components. Highest DPPH scavenging and PRAP activity was observed for the Lefkoşe sample (49.59 ± 0.19% (n = 5) and 812.77 ± 4.34 AU (n = 5)). Highest phytotoxic activity against Lemna minor L. was observed for the Salamis sample (100.0%). Lefkoşe sample showed the highest insecticidal activity (97.82 ± 1.79% mortality, S. granarius). Bornyl acetate/cis-chrysanthenyl acetate/hexadecanoic acid and camphor/santolinatriene/ yomogi alcohol chemotypes of C. coronarium are proposed from Cyprus samples according to cluster analysis of the oils together with the literature data.

Biologically Active Essential Oils against Stored Product Pests

Abstract Since the mid-1980s significant attention has been given to essential oils for their potential use in alternative pest management of stored products. Existing synthetic pesticides including methyl bromide and phosphine which are used as fumigants for pest management of stored products have serious adverse properties. These include their toxicity against nontarget organisms, long half-life in the field, and contamination of air/soil/water, etc. In addition to these adverse effects, stored product pests develop resistance to these control agents. The growing world population and increasing food demand together with increasing environmental concerns of society dictates an alternative method for the protection of precious food material. Essential oils produced by plants contain a vast array of secondary metabolites such as derivatives of monoterpenes, sesquiterpenes, diterpenes, aromatic compounds, hydrocarbons, and fatty acids. Plants produce essential oils for various purposes. Essential oils are used for attracting pollinators, deterring herbivores, effecting the growth of competitor plant species, and fighting fungal, bacterial, and viral plant diseases in plants. The volatile nature of essential oils and their known action on herbivores makes them a strong alternative in pest management of stored products. This chapter reviews the insecticidal activity of essential oils obtained from various plant species against main granary pests including Sitophilus granarius (L.), Sitophilus oryzae L., and Sitophilus zeamais Motschulsky species of Coleoptera: Curculionidae. In the scope of this chapter essential oil composition and type of activity observed against these pests are summarized, as well as potential areas of research and future prospects.