PHYTOCHEMICAL AND TOXICOLOGICAL STUDIES ON ESSENTIAL OILS OF AROMATIC PLANTS AGAINST Tetranychus urticae Koch.

Doctor of Philosophy, Cairo University, Faculty of Agriculture by Ehab Mostafa Bakr

Under supervision: Prof. Dr.: Ahmed Abd-El-Salam Barakat. Prof. Dr.: Hany Mahmoud Ashour Badawy. Prof. Dr.: Ahmed Mohamed Ibraheem Farrag.

Abstract

• This study was aimed to evaluate the acaricidal activity of some essential oils and some of their main component against the two spotted mite Tetranychus urticae. Essential oils used in this study were coriander herb and seed oils, cumin seed oil, eucalyptus oil, geranium herb oil, lemon grass oil, marjoram oil, parsley herb and seed oils, two species of mint peppermint and spearmint oils, sweet basil herb oil and bitter orange new leaves oil.
• Results showed that, parsley seed, sweet basil and coriander herb oils proved superiority against all of tested mite stages.
• Various changes were observed in biological aspects of survived mites protonymphs after exposure to LC₅₀ concentrations of tested oils. Most investigated oils significantly shortened adult oviposition period and decrease egg number per female.
• Forty-six compounds were identified in Parsley seed crude oil. Apiol was the dominant compound in Parsley seed crude oil, amounting to 41.49 %, followed by myristicine amounting to 39.6 %. Phenylpropanoid was the dominant chemical group amounting to 86.44 %.
  Forty-three compounds were identified basil crude oil. linalool was the dominant compound, amounting to 41.62 % followed by eugenol amounting to 20.51 % and cineole amounting to 9.19 %. Monoterpene was the dominant chemical group amounting to 79.79 % followed by Sesquiterpene amounting to 16.65 %.
  Thirty-eight compounds were detected in coriander herb oil. 2-decenal was the dominant compound amounting to 37.23 % followed by decanal amounting to 17.90 % and linalool amounting to 14.16 %. The dominant chemical group in coriander herb oil was aldehyds with total amount 75.22 % followed by monoterpenes amounting to 18.3%.
• After fractionation by TLC, the third fraction of parsley seed oil, which contains apiol, was the most potent fraction against mites adult females.
  In case of coriander herb oil the second fraction, which contains decanal (70.70 %), undecanal (16.50 %) and tetradecanal (12.80 %) proved to be the most potent fraction.
• Out of the standard materials: cinole, decanal, eugenol, limonene, linalool and undicanal. Eugenol was the most effective substance against mite eggs followed by limonene, decanal, undicanal, linalool and cinole with LC50 values 0.99, 1.49, 1.95, 1.96, 3.14 and 141.66 %, respectively.
  Lemonene was the most effective substance against mite protonymphs followed by eugenol, linalool, dicanal, undicanal and cinoele with LC50 values 0.28, 0.53, 0.97, 1.00, 1.45 and 2.41 %, respectively. Also against mite adults lemonene proved to be the most effective substance followed by eugenol, decanal, linalool, undicanal and cineole with LC50 values 0.59, 0.71, 1.03, 1.34, 1.65, and 3.06 %, respectively.