Decline and death of pine trees in the Fushan Botanical Garden in 1994 were demonstrated to be primarily caused by the pine wood nematode, Bursaphelenchus xytophilus, according to our etiological studies. Our survey also indicated that seven Pinus species including: Taiwan armand pine (P. armandii var. mastersiana), slash pine (P. clliottii), Luchu pine (p. luchuensis), Mexican weeping pine (P. patula), loblolly pine (P. taeda), Taiwan red pine (P. taiwanensis) and Japanese black pine (P. thunbergii) were naturally infected by pine wood nematodes. Based on disease incidence, Japanese black pine and Taiwan red pine were the most susceptible species; more than 50% of the investigated plants were infected either at the nursery or at the gymnosperm area. The susceptible Japanese black pine and Luchu pine consistently yielded higher nematode populations than the resistant loblolly and slash pines. Populations of the pine wood nematode recovered from naturally infected pines at the gymnosperm area were 562, 340, 182, 32, 22, and 9 individuals for Luchu pine, Japanese black pine, Taiwan red pine, slash pine, loblolly pine, and Mexican weeping pine, respectively.