Termiticidal Activity of Bio-oil from Hydrothermal Carbonization of Tobacco Stem against the Asian Subterranean Termite Coptotermes gestroi (Blattodea: Rhinotermitidae)

Abstract

Bio-oil from hydrothermal carbonization of tobacco (Nicotinia tabacum L) stem using Virginia and Native varieties from the Philippines were investigated for its termiticidal activity against the Asian subterranean termite Coptotermes gestroi Wasmann (Blattodea: Rhinotermitidae). Results of laboratory no-choice and choice feeding tests indicated that bio-oil from Virginia and Native tobacco stem was toxic or not palatable to C. gestroi at 5% concentration resulting in high mortality after 3-5 days of exposure and prevented termite feeding on treated filter paper. At lower concentration from 0.5% to 1%, termite mortality decreased significantly but remained relatively high. Bio-oil from the Native tobacco appeared to be more potent than that from Virginia at the 0.1 to 0.5% concentration. Choice feeding test suggested that C. gestroi exhibited anti-feeding behavior on filter papers treated with 5% or more bio-oil as shown by non-consumption of treated material. In all concentrations tested it indicated that tobacco bio-oil was not repellent to C. gestroi. GC-MS analyses of the chromatogram identified the chemical components of waste Virginia and Native tobacco stem bio-oil to be mostly organic acids and aromatic compound which reportedly have a wide spectrum of activity against various insect pests.