关键词: 松材线虫病, 松材线虫, 疫木处理, 木腐真菌, 松墨天牛

Abstract:

Objective: This study aimed to seek a new technology with high efficiency and environmental protection for treating the infected wood of pine wood nematode. Through indoor and field experiments,we screened wood-rot fungi that can effectively degrade the infected trees by pine wood nematode and inhibit the movement of pine wood nematodes in the diseased trees,which would provide basis for the development of new ways to eliminate pine wood nematode infected trees. Method: A total of 19 wood rot fungi were initially screened from the decaying pine samples using selective medium. Approximately 2 000 pine wood nematodes were co-cultured on different kinds of wood rot fungi,and the strains that could inhibit the growth and reproduction of Bursaphelenchus xylophilus were screened out. The decomposing ability of wood rot fungi to pine was determined by measuring the weight loss rate of Pinus thunbergii infected by wood rot fungi. A field experiment was carried out to select the strains which can effectively inhibit the propagation of B. xylophilus and degrade pine wood. The nematode-infected trees were inoculated with the liquid shaking culture mycelium. After four months of treatment,the number of pine wood nematodes in the whole section of the infected trees was analyzed. From May to June,the wood samples (0.5-1 cm) around the pupal chamber of longicorn beetles were collected to analyze the number of B. xylophilus in the wood samples around the pupal chamber. At the same time,the eclosion longicorn beetles were regularly captured in the wire mesh cover to analyze the number of nematodes carried by the eclosion longicorn. Result: Seven strains of wood rot fungi with strong ability to inhibit the propagation of B. xylophilus and degrade wood were screened out in the laboratory. After 8 days of culture on the plate of strain J5-2 out of the 7 strains,only 18±10 nematodes were isolated from each plate,while no B. xylophilus was isolated from the plates of Laetiporus sulphureus and Pleurotus ostreatus. Among the tested strains,L. sulphureus had the strongest ability to degrade pine wood. After 4 months of infection,the weight loss rate of samples reached 22.82%,followed by strain S4,which caused 21.68% loss of wood block weight. The field experiment showed that the number of B. xylophilus in infected wood was reduced after inoculation with 7 kinds of wood rot fungi for four months. Strain J5-2,L. sulphureus and strain S4 were able to reduce the number of nematodes in pupal chamber by more than 65%,and the number of nematodes carried by longicorn beetles was less than 200 per head. Strain J5-2 had the best killing effect and reduced the number of nematodes by 72%. The average number of B. xylophilus per longicorn beetle was only 15±4,and the maximum carrying capacity was only 60. Strain J5-2 was identified as Ceriporia. Conclusion: Strain J5-2,L. sulphureus and P. ostreatus have obvious inhibition effect on B. xylophilus. L. sulphureus and strain S4 have strong ability to degrade wood. After treatment,strain J5-2,L. sulphureus and S4 have the best effect,and they can reduce the number of nematodes by more than 65%. The utilization of wood rot fungi is a promising way to deal with pine wood nematode-infected wood in situ,which is worthy of further study.

Key words: pine wilt disease, Bursaphelenchus xylophilus, diseased wood treatment, wood rot fungi, Monochamus alternatus