Evaluation of insecticidal activity of the essential oil of Allium chinense G. Don and its major constituents against Liposcelis bostrychophila Badonnel

Water-distilled essential oil from the dried bulbs of Allium chinense (Liliaceae) was analyzed by gas chromatography-mass spectrometry (GC-MS). Eighteen compounds, accounting for 98.4% of the total oil, were identified and the main components of the essential oil of A. chinense were methyl allyl trisulfide (30.7%), dimethyl trisulfide (24.1%), methyl propyl disulfide (12.8%) and dimethyl disulfide (9.6%) followed by methyl allyl disulfide (3.4%) and methyl propyl trisulfide (3.6%). The essential oil exhibited contact toxicity against the booldice (Liposcelis bostrychophila) with an LC50 value of 441.8 mu g/cm(2) while the two major constituents, dimethyl trisulfide and methyl propyl disulfide had LC50 values of 153.0 mu g/cm(2) and 738.0 mu g/cm(2) against the booldice, respectively. The essential oil of A. chinense possessed strong fumigant toxicity against the booklice with an LC50 value of 186.5 mu g/l while methyl ally! trisulfide (LC50 = 90.4 mu g/l) and dimethyl trisulfide (LC50 = 1142 mu g/l) exhibited stronger fumigant toxicity than methyl propyl disulfide (LC50 = 243.4 mu g/l) and dimethyl disulfide (LC50= 340.8 mu g/l) against the booklice. The results indicated that the essential oil and its major constituents have potential for development into natural insecticides or fumigants for control of insects in stored grains. (C) 2014 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society. Published by Elsevier B.V. All rights reserved.