Gibberella circinata (anamorphic stage Fusarium circinatum) is the causal agent of pine pitch canker. The disease almost exclusively affects Pinus species, but was also described to occur on Douglas-fir (Pseudotsuga menziesii). This disease is a serious threat to the pine forests, due to extensive tree mortality, reduced growth and timber quality. Multiple branch infection may cause severe crown dieback and eventually lead to the death of the tree. This aggressive fungus may also cryptically infect the Pinus seeds and may cause damping-off in seedlings. The fungus is officially reported in the USA, Mexico, Haiti, South Africa, Japan, Chile (Anonymous 2005) and it has recently been reported in the EPPO region. In Spain and France G. circinata is under eradication and in Italy the pest organism has been eradicated. The pathogen is subject to EC emergency measures and there are requirements for MS to conduct surveys. In nurseries there had been findings in Spain, Portugal and France; it has been found in forests, parks and gardens in Spain. The first aim of this project is to ring test available and widely used detection methods and to provide validation and performance data for each of them. The validation data provided by this project will be useful to help the reference laboratories and mandated diagnostic laboratories to choose and implement efficient pine seed testing regarding this pathogen. The second aim is to provide an agreement about the sample sizes of pine seeds for testing. All the pine seed samples used for this project will be artificially contaminated with known quantities of the target pathogen. Preliminary tests should ensure the homogeneity of the different samples produced for the different levels of infestations and the different sample sizes. Preliminary investigation will be needed to explore the ISPM N°31 standard (International Plant Protection Convention 2008), and to determine which range of sample size should be assessed during this collaborative research project.