Antitermitic activities of Shisham (Dalbergia sissoo Roxb.) heartwood extractives against two termite species
B Hassan, M Mankowski, G Kirker, S Ahmed, M Misbah ul Haq
Shisham (Dalbergia sissoo) heartwood extractives were investigated for antitermitic activities against Heterotermes indicola and Reticulitermes flavipes. Heartwood extractives were removed from wood shavings by soxhlet extraction using (2:1) ethanol: toluene as the solvent system. Filter paper bioassays were conducted against both species to observe concentration dependent feeding response and mortality of termites. Results indicated that the highest termite mortality occurred at 10 mg/ml with a LC50 at 5.54 and 3.89 mg/ml against H. indicola and R. flavipes, respectively. Shisham extractives showed more repellency and antifeedant activity against H. indicola compared to R. flavipes. In choice and no-choice feeding bioassays with extracted and un-extracted Shisham wood blocks, increased wood loss due to termite feeding was observed on extracted blocks compared to un-extracted blocks. Higher termite mortality was also observed after feeding on un-extracted blocks compared to extracted blocks. Results also showed that extractives from Shisham imparted resistance to vacuum-pressure treated Southern pine (SYP, Pinus taeda L.) and Cottonwood (CW, Populus deltoides) against both species. These results suggest that Shisham extractives have antitermitic properties and may be potentially useful in the development of environment friendly termiticides.