Comparison of pathogenic potential of Bursaphelenchus species on conifer seedlings between greenhouse and outdoor conditions

Bursaphelenchus xylophilus is a serious threat to the European conifer forests. In Turkey, four Bursaphelenchus species (B. mucronatus, B. sexdentati, B. anamurius and B. vallesianus) were isolated from wilted pine trees. To determine the effects of Bursaphelenchus species on the wilting of pine trees, a pathogenicity study was conducted comparing greenhouse and outdoor conditions. Three-year-old seedlings of Pinus nigra, P. sylvestris and P. pinaster were used for inoculation tests. Approximately 1000 (+/- 100) nematodes of all life stages in 0.5 ml distilled water were inoculated into each seedling. The first wilting symptoms were observed in the fifth week. Mortalities occurred between the 5th and 13th weeks of the study. B. mucronatus was the most pathogenic nematode species. The most susceptible seedling species was P. pinaster, and P. nigra was the most resistant species. The mean number of wilted seedlings differed significantly among nematode species and seedling species but not between greenhouse and outdoor conditions.