There is widespread concern among scientists and land managers that Phytophthora ramorum may be accidentally introduced into oak-dominated eastern U.S. forests through the transfer of the pathogen from infected nursery plants to susceptible understory forest species (for example, Rhododendron spp.) at the forest-urban interface. Inspection programs can be made more efficient by identifying loca...

This paper examines the first year results from a silvicultural study of American, hybrid (BC2F3) and Chinese chestnut seedlings (Castanea spp. Mill.) on the Daniel Boone National Forest in southeastern Kentucky. After one year, no significant differences in growth were found among the silvicultural treatments. Hybrids and Chinese seedlings added significantly more height growth than the Americ...

Three novel endophytic streptomycetes have been isolated and characterized from plants with ethnobotanical uses on the Malay Peninsula including: Thottea grandiflora (family -Aristolochiaceae), Polyalthia spp. (family -Annonaceae), and Mapania sp. (family -Cyperaceae). Each isolate, as studied by scanning electron microscopy, has small hyphae, and produces typical barrel-shaped spores arising b...

Phytophthora species are well-known as destructive plant pathogens, especially in natural ecosystems. It is ironic, therefore, how little is known regarding the Phytophthora diversity in South African natural woody ecosystems. In this study, Phytophthora species were isolated using standard baiting techniques from 182 soil and water samples and these were identified based on ITS and coxI sequen...

Phytophthora species are devastating plant pathogens in both agricultural and natural environments. Due to their significant economic and environmental impact, there has been increasing interest in Phytophthora genetics and genomics, culminating in the recent release of three complete genome sequences (P. ramorum, P. sojae, and P. infestans). In this study, genome and other large sequence datab...

A number of fine root pathogens, including Phytophthora cinnamomi, Pythium ultimum var. ultimum, Pythium undulatum, Pythium violae, Fusarium sp., and two incompletely identified Verticillium species, were isolated from soils taken from under Scots pine trees at five sites in north Scotland, including semi-natural forests and plantations. At least two root pathogens were recovered from each fore...

Genomes of the plant-pathogenic genus Phytophthora are characterized by small duplicated blocks consisting of two consecutive genes (2HOM blocks) and by an elevated abundance of similarly aged gene duplicates. Both properties, in particular the presence of 2HOM blocks, have been attributed to a whole-genome duplication (WGD) at the last common ancestor of Phytophthora. However, large intraspeci...

The ability of two different flow cytometers, the Microcyte (Optoflow) and the PAS-III (Partec), to differentiate sporangia of the late-blight pathogen Phytophthora infestans from other potential airborne particles was compared. With the PAS-III, light scatter and intrinsic fluorescence parameters could be used to differentiate sporangia from conidia of Alternaria or Botrytis spp., rust uredini...

Castanea is a hardwood forest genus of considerable agro-economic importance for both timber and nut production. Chestnuts are one of the most significant nut crops in the temperate zone. However, this species is threatened by pollution, social factors, economical changes, and two major fungal diseases: ink disease (Phytophthora spp.), and chestnut blight canker (Cryphonectria parasitica). Simi...