Promotion and Prevention of Growth of Pine Wilt Nematode (Bursaphelenchus xylophilus) by Fungi

Abstract

The pine wilt nematode, Bursaphelenchus xylophilus usually grows well on a mycelial bed of Botrytis cinerea. A variety of fungi isolated from forest soil also supports the multiplication of the nematode. Among 99 strains tested, 13 strains promoted nematode growth most effectively when reared on mycelial beds at 30°C for 7 days. The nematode multiplied to over 10⁵ after an inoculation of 10³ heads per petri dish from two strains of Pestalotia species and one strain of Verticicladiella and Penicillium species. Most other fungi tested also supported nematode growth but less effectively than Botrytis cinerea. They included Penicillium, Cladosporium, Eladia, Gliomastix, Acremonium, Helminthosporium, Humicola, and Aspergillus species. On the other hand, some fungi prevented nematode multiplication including Alternaria, Mucor, Penicillium, Trichoderma, Nectria, Aspergillus, Cunninghamella, Paecilomyces, Pestalotia, Pestalotiopsis, Trichothecium, and Phomopsis species. These fungi did not show any nematofagous activity, and the prevention activity might be ascribed to the unfavorable properties of their mycelia for nematode growth.
Two strains of Phomopsis species exhibited strong nematocidal activity in cultural liquid, reaching 96.9_??_99.6% mortality after 48 hr incubation.