Resistance of eastern redcedar

This study investigated resistance ofexperimental particleboard-chip panels manufactured from eastern redcedar (Juniperus virginiana L.) to feeding by the wood-destroying eastern subterranean termite, Reticulitermesjlavipes (Kollar). Eastern redcedar raw chips with or without foliage, and 2.5 by 2.5 by 1.3-cm rectangular blocks of single-layer or triple-layer particleboard-chip panels with or without foliage were exposed to foraging termites. Chips and blocks sustained some damage by feeding termites but were not equally preferred. In choice tests, where all chips and panel blocks plus controls were simultaneously available to foraging termites, radiata pine sustained 44.6 percent weight loss compared with 2.1 to 6.1 percent weight loss for chips and blocks. In no-choice feeding tests, where termites received only one type of food resource, raw redcedar chips and panel blocks sustained less feeding damage compared with radiata pine sapwood, and termite worker survival was less than 24 percent after 12 weeks, compared with more than 84 percent survival in radiata pine controls. Additionally in no-choice tests, chips and blocks lost 4.9 to 6.3 percent weight, whereas radiata pine controls sustained 9.2 percent weight loss. Based on these findings, redcedar panels tested exhibited moderate resistance against termite damage. Subterranean termites are widespread pests of wood structures and wood products in North America and cause extensive damage annually (Sharma 1993). These wooddestroying pests are a continuous threat to wood composite materials in residential and commercial structures. Wood composite panels used extensively in building construction are found in millions of homes in the United States and abroad. However, manufactured particleboard and other wood-based panel products are seldom evaluated for resistance to attack by subterranean termites. Because termites are cryptic, and severe damage often occurs but remains undetected until structural wood components are beyond repair, it is important to know the susceptibility or resistance ofthese materials to damage by termites. If panels made from eastern redcedar (Juniperus virginiana L.) are resistant to termite damage, a beneficial use of this pest tree species could result. Natural resistance ofwood to termite attack is due in part to chemicals deposited during heartwood formation (Carlsson et al. 1952, Erdtman and Topliss 1957, Kumar 1971, Carter and Bea11982, Sims 1988). Concentrations of biologically active chemicals usually differ among trees within a species, and can vary among locations in individual trees (Rudman and Gay 74 1967). A specific chemical that causes resistance to insects may occur only in wood of one tree species, and not others. Woods containing different chemicals can be expected to differ in their ability to resist wood-destroying insects (Beal et al. 1974, Carter and Smythe 1974, Carter and Mauldin 1981, Grace and Yamamoto 1994). Heartwood is generally more resistant to insects than sapwood, and termites readily survive on sapwood but not on heartwood because ofthe latter's extractive chemical content. The authors are, respectively, Associate Professors, Dept. of Entomology and Plant Pathology ([email protected]), and Dept. of Forestry ([email protected]), and Professor, Statistics Dept. and Assoc. Dean, Graduate College (mark.payton@okstate. edu), Oklahoma State Univ., Stillwater, Oklahoma 74078. We thank Don C. Arnold and Craig R. McKinley for reviewing a draft of this manuscript. The authors respectively acknowledge the financial support provided by the Food and Agri. Products Center (FAPC), Oklahoma State Univ., Stillwater, Oklahoma. This work was approved for publication by the Director ofthe Oklahoma Agri. Expt. Sta., and supported in part under Project H-2480. This paper was received for publication in January 2007. Article No. 10300. *Forest Products Society Member. ©Forest Products Society 2007. Forest Prod. J. 57(11):74-79.