Comment submitted by C. J. Fettig, Pacific Southwest Research Station

I wish to provide comment on docket EPA-HQ-OPP-2006-0801 concerning the petition to revoke tolerances established for carbaryl submitted by Washington Toxics Coalition. Carbaryl is considered by many to be an excellent choice for preventing bark beetle attacks on individual trees in the western US (Hastings et al. 2001). Others have commented that in many respects, carbaryl is still the most effective, economically viable, and ecologically-compatible insecticide available for this use (Fettig et al. 2006a). Carbaryl is generally regarded as posing little or no threat to warm-blooded animals (Hastings et al. 2001). It is readily adsorbed in soil where carbaryl rapidly degrades (Shealy et al. 1997), and is therefore unlikely to contaminate ground water (Hastings et al. 2001). Carbaryl was one of the least toxic chemicals evaluated on six freshwater mussels and of lower toxicity than permethrin (Milam et al. 2005). Hoy and Shea (1981) studied the effects of lindane, chlorpyrifos and carbaryl on a California pine forest soil arthropod community and concluded that carbaryl was the least disruptive to that community. Swetzey et al. (1982) evaluated the nontarget effects of topically applied carbaryl, lindane and chlorpyrifos on two bark beetle predators. Carbaryl was relatively nontoxic to one species and less toxic than either lindane or chlorpyrifos to the other. In general, total application costs for carbaryl are lower than that of alternatives, such as bifenthrin (DeGomez et al. 2006, Fettig et al. 2006a) and permethrin+C (Fettig et al. 2006b). Carbaryl provides at least two field seasons of protection with a single application for most western tree species (Fettig et al. 2006a, b). In general, the alternatives, primarily pyrethroids, require repeated annual applications if multi-year control is desired. Washington Toxics requests this action to obtain what they believe would be proper application of the safety standards under FIFRA, FFDCA and FQPA. Based on my professional experience and a rather thorough knowledge of the literature, I disagree with their position. Every year millions of trees are killed by bark beetles throughout North America. This represents a direct loss of revenue and often reduces recreational opportunities, negatively affects water quality, and increases the risk and severity of wildfire. Carbaryl is an essential tool to protect individual trees from bark beetle attack and its use poses few risks. Literature Cited--- DeGomez, T.E., C.J. Hayes, J.A. Anhold, J.D. McMillin, K.M. Clancy, and P.P. Bosu. 2006. Evaluation of insecticides for protecting southwestern ponderosa pines from attack by engraver beetles (Coleoptera: Curculionidae, Scolytinae). J. Econ. Entomol. 99: 393-400. Fettig, C.J., K.K. Allen, R.R. Borys, J. Christopherson, C.P. Dabney, T.A. Eager, K.E. Gibson, E.G. Hebertson, D.F. Long, A.S. Munson, P.J. Shea, S.L. Smith, and M.I. Haverty. 2006a. Effectiveness of bifenthrin (Onyx?) and carbaryl (Sevin? SL) for protecting individual, high-value trees from bark beetle attack (Coleoptera: Curculionidae: Scolytinae) in the western United States. J. Econ. Entomol. 99: 1691-1698. Fettig, C.J., T.E. DeGomez, K.E. Gibson, C.P. Dabney, and R.R. Borys. 2006b. Effectiveness of permethrin plus-C (Masterline?) and carbaryl (Sevin? SL) for protecting individual, high-value pines from bark beetle attack. J. Arbor. Urban For. 32: 247-252. Hastings, F.L., E.H. Holsten, P.J. Shea, and R.A. Werner. 2001. Carbaryl: a review of its use against bark beetles in coniferous forests of North America. Environ. Entomol. 30: 803-810. Hoy, J.B. and P.J. Shea. 1981. Effects of lindane, chlorpyrifos, and carbaryl on a California pine forest soil arthropod community. Environ. Entomol. 10: 732?740. Milam, C.D., J.L. Farris, F.J. Dwyer, and D.K. Hardesty. 2005. Acute toxicity of six freshwater mussel species (Glochidia) to six chemicals: implications for daphnids and Utterbackia imbecillis as surrogates for protection of freshwater mussels (Unionidae). Arch. Environ. Contam. Toxicol. 48: 166-173. Shealy D.B., J.R. Barr, D.L. Ashley, D.G. Patterson, D.E. Camann, and A.E. Bond. 1997. Correlation of environmental carbaryl measurements with serum and urinary 1-naphthol measurements in a farmer and his family. Environ. Health Pers. 105: 510?513. Swezey S.L., M.L. Page, and D.L. Dalsten. 1982. Comparative toxicity of lindane, carbaryl, and chlorpyrifos to the western pine-beetle and two of its predators. Can. Entomol. 114: 397?401.