Nursery and field experiments to test conifers susceptibility to Pitch Canker disease

Abstract

Fusarium circinatum is the causal agent of the Pitch Canker disease, which was first detected in Spain in 2004. Not only Pinus species seedlings in nurseries were affected but also Pinus radiata plantations in the forest. Thus, the pathogen has spread out over several pine forests of northern Spain producing substantial economical losses. Consequently, a resistant and viable pine species is required as alternative. The susceptibility of fifteen conifer species was tested in laboratory conditions measuring the germination of seeds and mortality of the emerged seedlings. In addition, a complementary field experiment was also established to evaluate natural infection of different conifers. Chamaecyparis lawsoniana and Sequoiadendron giganteum obtained the best results in the assay developed in the laboratory. On the contrary, the whole of P. radiata seedlings died, confirming that it is the most susceptible species, despite this species (together with Pinus pinaster) showed the highest growth in the control stand of the field assay. Natural infection did not occur during the first two years after plantation. Key words: Susceptibility, conifer, Fusarium circinatum, pitch canker, pathogenicity.