01968nas a2200193 4500008004100000022001400041245009300055210006900148260002900217300001400246490000700260520137500267100001301642700001401655700001701669700001401686700001901700856005501719 2010 eng d a1439-032900aInvolvement of Phytophthora species in white oak (Quercus alba) decline in southern Ohio0 aInvolvement of Phytophthora species in white oak Quercus alba de bBlackwell Publishing Ltd a430–4420 v403 a

This study was initiated to investigate the possible role of Phytophthora species in white oak decline (Quercus alba) in southern Ohio at Scioto Trail State Forest. Surveys demonstrated the presence of four species of Phytophthora including one novel species. By far, the most common species was P. cinnamomi; P. citricola and P. cambivora were isolated infrequently. In few instances, P. cinnamomi was isolated from fine roots and necroses on larger roots. No special pattern of incidence was found, but P. cinnamomi was more commonly isolated from greater Integrated Moisture Index values suggesting moist lower bottomlands favour this Phytophthora species. When tree crown condition was examined relative to the presence of Phytophthora, no significant association was found. However, roots of declining P. cinnamomi-infested trees had 2.5 times less fine roots than non-infested and healthy trees, which was significantly different. The population densities of P. cinnamomi from declining trees were significantly greater than from healthy trees, suggesting increased pathogen activity that has the potential to cause dieback and decline and possibly the cause of a reduced fine root amount found on declining trees.

1 aBalci, Y1 aLong, R P1 aMansfield, M1 aBalser, D1 aMacDonald, W L uhttp://dx.doi.org/10.1111/j.1439-0329.2009.00617.x