Abstract

Onion oil and its components were tested for their nematicidal activity against the pine wood nematode, Bursaphelenchus xylophilus, with 96-well plate bioassays. Responses varied with test materials and concentration. Good nematicidal activity against male, female and juvenile nematodes of B. xylophilus was achieved with onion oil. The LC50 values of onion oil against male, female and juvenile pine wood nematodes were 17.6, 13.8 and 12.1 μg ml−1, respectively. Analysis by gas chromatography-mass spectrometry led to the identification of four major sulphur compounds: propyl disulphide, propyl trisulphide, methyl propyl disulphide and methyl propyl trisulphide. These four compounds and propyl sulphide and methyl propyl sulphide were tested individually for their nematicidal activities against pine wood nematode. LC50 values of propyl trisulphide and methyl propyl trisulphide against juvenile nematode were 5.0 and 22.9 μg ml−1, respectively. Other sulphur compounds showed weak activity.

In: Nematology

Abstract

Commercial essential oils from 29 plant species were tested for their nematicidal activity against the pine wood nematode, Bursaphelenchus xylophilus. Good nematicidal activity against B. xylophilus was achieved with essential oils of Gaultheria fragrantissima and Zanthoxylum alatum. GC-MS analysis of the corresponding oils led to the identification of two and ten major compounds, respectively. Four compounds, methyl salicylate, ethyl salicylate, methyl trans-cinnamate and ethyl trans-cinnamate, were tested individually for their nematicidal activities against the pine wood nematode. Methyl and ethyl salicylates showed strong nematicidal activity at concentration of 2.0 mg ml–1. Concentrations of 1.0 mg ml–1, as well as lower concentrations showed only minor effects. Another compound, methyl trans-cinnamate, showed 100% activity at concentrations of 0.0625-2.0 mg ml–1. With ethyl trans-cinnamate, 100% mortality was observed at concentrations of 0.25-2.0 mg ml–1. The essential oils and their components described herein merit further study as potential nematicides against the pine wood nematode.

In: Nematology

Abstract

Extracts from 40 medicinal plant species in 27 families were tested for their nematicidal activity against the pine wood nematode, Bursaphelenchus xylophilus, in 96-well plate bioassays. Responses varied with plant material and concentration. Extracts of Acorus gramineus (Araceae), Asiasarum sieboldi (Aristolochiaceae), Illicium verum (Illicaiceae) and Kaempferia galanga (Zingiberaceae) showed nematicidal activity against male, female and juvenile nematodes of B. xylophilus at 2000 μg ml−1. Among test plant species, Kaempferia galanga showed the most potent nematicidal activity. As K. galanga was the most nematicidally active of the 40 species, the extracts were chromatographically fractionated and two cinnamates, ethyl trans-cinnamate and ethyl p-methoxycinnamate, were discovered to be responsible for much of the activity. The nematicidal activity of ethyl trans-cinnamate and ethyl p-methoxycinnamate was 100% at 60 μg ml−1.

In: Nematology

Abstract

Plant essential oils from 43 plant species were tested for their nematicidal activities against the pine wood nematode, Bursaphelenchus xylophilus. Responses varied with plant material and concentration. Good nematicidal activity against male, female and juvenile nematodes of B. xylophilus was achieved with essential oils of Cinnamomum verum, Leptospermum petersonii, Asiasarum sieboldi, Boswellia carterii, Pimenta racemosa, Cymbopogon citratus, Mentha spicata, clove and garlic. Garlic and cinnamon oils showed the most potent nematicidal activity among the plant essential oils. Analysis by gas chromatography-mass spectrometry led to identification of three major compounds from garlic and two from cinnamon oil. These five compounds from two essential oils were tested individually for their nematicidal activities against the pine wood nematode. Responses varied with compounds and dose. LC50 values of diallyl trisulphide, diallyl disulphide and cinnamyl acetate against juvenile nematode were 2.79, 37.06 and 32.81 μl−1, respectively. The essential oils described herein merit further study as potential nematicides against the pine wood nematode.

In: Nematology