In 2004 and increasingly through 2006, a new disease of Pinus radiata, referred to as ‘Daño Foliar del Pino’ (DFP) appeared in the Arauco province of Chile and subsequently spread to other areas in central Chile planted with radiata pine. The disease is typified by needle infections, exudation of resin at the bases of the needle bundles and, in younger trees, necrotic lesions in the cambium which eventually girdle the branches. In 2007 a previously unknown Phytophthora sp. was isolated from needle tissue. In 2008 it was formally described as Phytophthora pinifolia by Alvaro Duran and colleagues from Bioforest S.A., Concepción, Chile and the Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, South Africa (Duran et al. 2008). This new species is characterized by unbranched sporangiophores and non-papillate, sub-globose to ovoid sporangia that are occasionally caducous. Sexual structures were not observed. Phytophthora pinifolia is the first Phytophthora known to be associated with needles and shoots of a Pinus sp. Etymology : ‘pinifolia’ refers to the occurrence of the organism on the needles of Pinus radiata.
Cultures on cornmeal agar selective medium were submerged with coralloid hyphae, while carrot agar (CA) and V8 cultures were fluffy with a regular to rosaceous or petallate margin. Sporangia formed abundantly in soil water and were generally absent in agar culture. Sporangia were borne on predominantly unbranched sporangiophores and were non-papillate, sub-globose to ovoid. Free sporangia with pedicels were occasionally observed after agitation of liquid cultures. Oogonia did not form in single culture or when paired with A1 or A2 tester isolates of heterothallic species.