Bursaphelenchus juglandis n. sp. (Nematoda: Aphelenchoididae), an associate of walnut twig beetle, Pityophthorus juglandis, the vector of thousand cankers disease

What is it about?

Bursaphelenchus juglandis n. sp. was isolated from the walnut twig beetle Pityophthorus juglandis, and walnut trees, Juglans spp. with symptoms of thousand cankers disease in California, USA. Based on analysis of three rRNA genes and morphological features (three lines in lateral field, small arched vulval flap in female, broad spicule with two lines along core and small cucullus, digitate dorsally bent condylus and male tail pattern of 5 papilliform papillae and one pair of glandpapillae P5, and curved conical female tail), the new species belongs to the Abietinus group of Bursaphelenchus. It differs from species of the Abietinus group by the presence of a cephalic disc with lateral lip sensillae at the disc border, and in thick spicules with the capitulum surface almost parallel to the virtual direct line extending from the spicule ending. An emended diagnosis, tabular polytomous identification key and compendium of species with the lists of their vectors, plant hosts and distribution were provided for the Abietinus group. The diagnostics of propagative developmental stages was prepared including sex differences; the transmissive dauer stage was identified as DJ3; its description was given with sexual differences. A molecular phylogeny of the genus Bursaphelenchus was provided based on the analysis of partial 18S rRNA, ITS rRNA and D2-D3 expansion fragments of 28S rRNA gene sequences. A PCR with a species-specific primer was developed for detection of B. juglandis n. sp.

Featured Image