Phytophthora spp. Associated with Forest Soils in Eastern and North-Central U.S. Oak Ecosystems

Y. Balci, S. Balci, J. Eggers, W. L. MacDonald, J. Juzwik, R. P. Long, K. W. Gottschalk
2007 Plant Disease  
Phytophthora spp. associated with forest soils in eastern and north-central U.S. oak ecosystems. Plant Dis. 91:705-710. A survey of soils associated with oak species was conducted in 2003 and 2004 in Indiana, Illinois, Maryland, Michigan, Minnesota, Pennsylvania, Ohio, West Virginia, and Wisconsin to investigate the occurrence of Phytophthora spp. Soils taken from around the base of healthy and declining oak trees were flooded with H 2 O and Quercus robur leaflets were used as bait for
more » ... ora spp. From 829 soil samples collected near trees, 21% were positive for Phytophthora spp., with 55% of the 125 sites surveyed yielding a Phytophthora sp. Phytophthora cinnamomi was the most frequently isolated species, representing 69.4% of the Phytophthorainfested sites surveyed. Other species, in decreasing order of isolation frequency were Phytophthora sp. 2, P. citricola, P. europaea, P. cambivora, P. quercina-like isolates, and Phytophthora sp. 1. No significant association was found between the presence of Phytophthora organisms and site characteristics such as latitude, elevation, soil pH, or the crown condition of the trees. However, in P. cinnamomi-infested sites, a significant association was found with the deteriorating crown status of Q. alba and the presence of P. cinnamomi. The absence of P. cinnamomi above the 40ºN latitude range also was noteworthy.
doi:10.1094/pdis-91-6-0705 fatcat:3pkoluhegvh5zoqz6k35rghdfu