Abstract:

【Objective】 In this study, we aimed to screen out wood-rot fungi, which can significantly reduce the quantity of Bursaphelenchus xylophilus, and consequently, to prevent nematodes from entering the pupal chamber before being transported by vector insects. In this way, the goal of blocking the infection cycle of B. xylophilus in the plague wood link can be achieved. These wood-rot fungi should also rapidly colonize and expand in the plague wood to quickly degrade the wood components and change the microenvironment of plague wood. This study provides a reference for the effective prevention and control of pine wilt disease. 【Method】 First, 2 000 pine wood nematodes were inoculated on different wood-rot fungi colonies on mature wood, and the effects of different wood-rot fungi on the growth and reproduction of B. xylophilus were determined by indoor plate experiments. Second, black pine wood blocks were inoculated with wood-rot fungi that can inhibit the growth and reproduction of B. xylophilus to explore its degradative effects on black pine wood. Through these two experiments, excellent wood-rot fungi that can significantly affect the growth and reproduction of B. xylophilus, and have the ability to decompose wood, were selected. Finally, the selected ideal wood-rot fungi were inoculated on a 60 cm long felled wood segment infected with the disease in the field after a large number of liquid cultures and solid culture propagation. The wood samples were drilled with electric drills at 120 and 150 days after inoculation. After splitting the wood segments, the wood samples around the passage of longicorn were collected to count the number of B. xylophilus in the collected wood samples. We compared the changes in the number of B. xylophilus in the blight wood before and after inoculation, and analyzed the effect of the wood inoculated with wood-rot fungi on the population of B. xylophilus in the blight. 【Result】 B. xylophilus could not survive in the plate culture of Poria cocos. The growth and reproduction of B. xylophilus were also significantly inhibited in colonies of Phanerochaete chrysosporium, B18, C11 and D16. The largest loss rate of wood quality inoculated with P. cocos was 7.30%. The decomposition rates of cellulose and hemicellulose were also the highest, with decomposition rates of 19.21% and 29.65%, respectively. Furthermore, the best decomposers of lignin were P. chrysosporium, with a decomposability of 31.59%. In the field inoculation experiment, the reduced number of B. xylophilus in the plague wood after inoculation with P. cocos was more significant than that in the other wood-rot fungi. After inoculation with the liquid mycelium and solid mycelium of P. cocos for 150 days, the number of B. xylophilus in the plague wood was reduced to its maximum, with a reduction rate of 74.51% and 65.78%, respectively. After inoculation with P. cocos liquid and mycelium culture, the number of B. xylophilus in the decay hole of longicorn decreased by 65.45%. 【Conclusion】 P. cocos had the best effect on both indoor and outdoor wood decomposition rates and reduced the number of B. xylophilus in the plague wood. The effect of the same type of inoculation liquid from wood-rot fungi culture mycelium was better than that after inoculation with solid culture mycelium. It is clear that using wood-rot fungi, which are not conducive to the growth and reproduction of B. xylophilus to eradicate the pine wilt disease plague wood, has technical feasibility, broad prospects, and extreme importance in its application. Therefore, it is worthy of a further research and development.

Key words: pine wilt disease, Bursaphelenchus xylophilus, plague wood, wood rot fungi, inoculation, pest control treatment