02190nas a2200169 4500008004100000245012800041210006900169300001200238490000700250520161400257100001701871700001501888700001701903700001701920700001701937856006601954 2011 eng d00aEffects of fuel reduction treatments on incidence of Phytophthora species in soil of a southern Appalachian Mountain forest0 aEffects of fuel reduction treatments on incidence of Phytophthor a811-8200 v953 a

The National Fire and Fire Surrogate Study was initiated to study the effects of fuel reduction treatments on forest ecosystems. Four fuel reduction treatments were applied to three sites in a southern Appalachian Mountain forest in western North Carolina: prescribed burning, mechanical fuel reduction, mechanical fuel reduction followed by prescribed burning, and a nontreated control. To determine the effects of fuel reduction treatments on Phytophthora spp. in soil, incidences were assessed once before and twice after fuel reduction treatments were applied. Also, the efficiency of the baiting bioassay used to detect species of Phytophthora was evaluated, and the potential virulence of isolates of Phytophthora spp. collected from forest soils was determined. Phytophthora cinnamomi and P. heveae were the only two species recovered from the study site. Incidences of these species were not significantly affected by fuel reduction treatments, but incidence of P. cinnamomi increased over time. In the baiting bioassay, camellia leaf disks were better than hemlock needles as baits. P. cinnamomi was detected best in fresh soil, whereas P. heveae was detected best when soil was air-dried and remoistened prior to baiting. Isolates of P. heveae were weakly virulent and, therefore, potentially pathogenic—causing lesions only on wounded mountain laurel and rhododendron leaves; however, isolates of P. cinnamomi were virulent and caused root rot and mortality on mountain laurel and white pine plants.

1 aMeadows, I M1 aZwart, D C1 aJeffers, S N1 aWaldrop, T A1 aBridges, W C uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-07-10-0505