Propagation of Bursaphelenchus xylophilus(Nematoda:Aphelenchoididae)on Fungi Growing in Pine-Shoot Segments

Abstract

The in vitro propagation of the pine wood nematode (PWN), Bursaphelenchus xylophilus, was investigated using pine-shoot segments colonized with fungi which associated with nematode-infected and/or healthy pine trees, Pinus densiflora and P. thunbergii. With exceptions of Penicillium sp., Verticillium sp. and 1 isolate of Trichoderma spp., all other tested fungi were suitable for nematode production. On the most suitable fungi, Ceratocystis sp., PWN population increased quickly, reached the maximum 4 weeks after inoculation and then decreased slowly. The dispersal third-stage larvae (L_III) appeared 2 weeks after inoculation, reached the maximum level when the total PWN population was also the highest, and remained high during the experimental period. The percentage L_III relative to the total PWN population therefore increased with time. The percentage of L_III was lower on Arthrobotrys sp. and on 2 isolates of Trichoderma spp. than on other tested fungi. The role of these fungi in natural pine stands was discussed with regard to the propagation and survival of PWN.