First Report of Bursaphelenchus mucronatus kolymensis Associated with Pinus sylvestris in Serbia

Abstract

Bursaphelenchus mucronatus kolymensis (Korentchenko) Braasch et al. (1), also referred to as the European type of B. mucronatus, is morphologically very similar to the pine wood nematode (PWN) B. xylophilus (Steiner & Buhrer) Nickle, the causal agent of pine wilt disease. The main morphological difference between the two species is the shape of the female tail mucro (3); however, some populations of PWN vary in mucro shape, which can lead to misidentification. Since PWN was found and identified for the first time in Portugal in 1999 (4), concern about the spread of PWN to pines and other conifers all over Europe has increased. Therefore, the PWN survey in every European country is essential. In 2011, the Serbian Ministry of Agriculture, Forestry and Water Management implemented phytosanitary measures for detection of PWN in the territory of the Republic of Serbia. In September 2013, wood samples were collected from a 40-year-old wilted Pinus sylvestris located on Divcibare Mountain, western Serbia. Nematodes were extracted by a modified Baermann funnel method. Nematode specimens (10 females and 10 males) were characterized by an Aphelenchoid-type esophagus, female vulva flap, mucro on the end of female tail, and males with paired arcuate spicules. Morphological identification matched that of B. mucronatus kolymensis (1). The specific morphometric evidence for this European type subspecies of B. mucronatus was sub-cylindrical female tail with mucro 3 to 4 μm long, digitate, well offset from tail (5). Species identification was confirmed by PCR-RFLP of the rDNA ITS region using one female and one male nematode separately (2). The sizes of restricted DNA fragments as determined with agarose gel and capillary electrophoresis were in compliance with reported data in the literature (2,4) and support the identification of the nematode as B. mucronatus kolymensis. To our knowledge, this is the first report of any species belonging to Bursaphelenchus genus in Serbia. The presence of B. mucronatus kolymensis in Serbia indicates the possibility of establishment and spread of PWN. Therefore, the measures taken in case of PWN occurrence should be prepared and training foresters to identify pine wilt disease symptoms should be encouraged in Serbia.