Antitermitic Properties of Cellulose Pads Treated with Bark Extractives

A study was undertaken to evaluate the feasibility of using bark extractives as a preservative treatment for wood to inhibit subterranean termite activity. Bark samples were collected from eleven species: Pinus strobus, P. virginiana, Tsuga canadensis, Quercus alba, Q. velutina, Q. prinus, Sassafras albidum, Juglans nigra, Carya ovata, Liriodendron tulipifera , and Robinia pseudoacacia . Cellulose paper pads (unbleached kraft) were treated with one of two bark extracts (A:H:W or 1% NaOH/Na 2 S) at 0.16, 0.67, and 0.83 g/ml treatment levels and evaluated for antitermitic properties. Complete termite mortality was observed after 4 weeks for paper pads treated with A:H:W bark extracts from the species Q. prinus, P. strobus, C. ovata , and S. albidum at both the 0.67 and 0.83 g/ml treatment levels. In addition, no termite survival was observed for paper pads treated with the A:H:W bark extracts from the species Q. alba, L. tulipifera , and T. canadensis at the 0.83 g/ml treatment level. Termite survival was observed for paper pads treated with A:H:W extracts at the 0.16 g/ml treatment level and with alkali extracts at the 0.16, 0.67, and 0.83 g/ml treatment levels for all bark species examined. No significant difference in termite mortality was observed between A:H:W bark extracts obtained from fresh or 1-year-old harvested bark. Feeding preference trials indicate that termites are attracted to A:H:W extracts obtained from C. ovata and J. nigra . Antitermitic trials with pentachlorophenol, copper naphthenate, and bark extracts at the 0.67 g/ml treatment level exhibited complete termite mortality; but the termites consumed more cellulose treated with bark extractives than with commercial preservatives. These results indicate that A:H:W bark extracts from the species Q. prinus, S. albidum, P. strobus and C. ovata show promise as a wood preservative, but additional studies are needed to isolate and identify the antitermitic extracts.