Bursaphelenchus Xylophilus From China Naturally Infected Host Populations Pathogenic To Pinus Massoniana Study

We sampled from our country the pine wood nematode new and old infected areas, a total of13locations and isolated and purified nematodes from the incidence wood of P. massoniana, P. elliottii, P. caribaea, P. tabulaeformis, Pinus armandii, and received18nematode populations. Though morphology observation and using the method of molecular rDNA-ITS-PCR combined with the construction of phylogenetic tree to identify nematode species, including that populations number1～14were Bursaphelenchus xylophilus and respectively named Nxy2～Nxy15; and populations number15～18were B. mucronatus and named Nxyml-Nxym4respectively, therefore it inferenced that the type of B. mucronatus was the East Asia type.Though inoculating22different nematode populations experiments it founds that nematode’s pathogencitity from different hosts is different. On the whole, these nematode populations whose host are Pinus massoniana, P. kesiya var. langbianensis, P. thunbergii, have strong pathogenic; whose host are P. elliottii and P. tabulaeformis have pathogenicity of medium; whose host are P. caribaea have weak pathogenicity. The same host plant, but different geographical populations of the pine wood nematode’s pathogenicity are also different. They are from ZheJiang Ningbo, ZheJiang Linan, ZheJiang Fuyang, ZheJiang Xinchang, GuangDong Huizhou which have pathogenicity stronger than ZheJiang Anji and GuangZhou Huadu. ZheJiang Ninghai pathogencity is relatively weak. The strains of B. mucronatus have also certain pathogenicity to P. massoniana whether on P. massoniana from ZheJiang or on Pinus armandii at altitude of1500m. And that the strain’s pathogenicity from ZheJiang Fenghua P. massoniana is stronger than some populations of pine wood nematode of pathogenic.Though the withered pine seedlings atter inoculation separated nematode, it fouds that the average number of larvas in dead pine seedlings is much higher than the number of adults; and the majority strains of the averge female is higher than male; and the average number of per gram seedlings of nematodes all they don’t have certain contact with pathogenic strength of nematodes. And we also found that all the pine wood nematodes used to inoculation female tail render finger type and tail end is wide circle, therefore they don’t tail tip in artificial culture conditions. But they were inoculated in the3-yeat old P. massoniana seedlings after, no whether dead pine seedlings or non-dead pine seedlings their female had short of the tail tip. and the average length of the tail tip was less than2u m. All of the strains of the B. mucronatus female tail don’t change before and after inoculation.Comprehensiveiy considering susceptible index, morbidity, mortality, the first infected date and morbidity of the first infected five factors to screed out that B. xylophilus Nxy61、 Nxy9、Nxy16、Nxy18、Nxy7are strong pathogenic strains, Nxy10、Nxy14are medium virulent strains, Nxy3、Nxy4are weak virulent strains; B. mucronatus Nxyml is strong virulent strain, Nxym3、Nxym4is weak virulent strain. Screening out the pathogenic strength of strains which can provide the basis material for group laboratory research the pine wood nematode pathogenesis on the futher.