Pathogenicity testing of four Bursaphelenchus species on conifer seedlings under greenhouse conditions

Abstract

The pinewood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer, J. Agric Res. 48, 1934, 949), Nickle (J. Nematol. 2, 1970, 375), is the causative agent of the pine wilt disease and causes serious damage to pine forests around the world. During a survey for the pinewood nematode, four other Bursaphelenchus species (Bursaphelenchus mucronatus, B. sexdentati, B. anamurius and B. vallesianus) were isolated from wilted pine trees in Turkey. To understand the effects of these Bursaphelenchus species on wilting of pine trees, a study was conducted under greenhouse conditions. Two-year-old seedlings of three pine species (Pinus nigra, P. brutia and P. pinea) and one cedar species (Cedrus libani) were used. Fifteen seedlings of each species were inoculated with nematodes and 10 seedlings of each species served as controls. The inoculum densities used for each seedling contained approximately 1000 (±100) nematodes of all life stages in 0.25 ml of distilled water. The first wilting symptoms were observed in the fifth week in all pine species but not in the cedar seedlings. All seeding mortality occurred between the 5th and 13th weeks of the study; no mortality was observed outside of this period. The most pathogenic nematode species was B. mucronatus, closely followed by the other species. The most susceptible seedling species was P. nigra, and C. libani was the most resistant species.

Comparison of pathogenic potential of Bursaphelenchus species on conifer seedlings between greenhouse and outdoor conditions

“…(Akbulut et al 2007b;Dayı & Akbulut 2012). No studies have been performed to determine differences in the pathogenic effects of the nematodes on pine seedlings between greenhouse and outdoor conditions in Turkey.…”

“…The inoculum density used for each seedling was approximately 1000±100 nematodes of all life stages in 0.5 ml of distilled water. The adjustment of desired inoculum concentration, the selection of inoculation point and inoculation processes were performed at the same way done previously by Dayı & Akbulut (2012). All inoculation procedures were repeated identically for both greenhouse and outdoor treatments.…”

“…Before inoculation, laboratory cultures of B. mucronatus, B. sexdentati, B. vallesianus and B. anamurius were multiplied on Botrytis cinerea Pers. in malt agar at 25°C for 7-10 days as done previously by Dayı & Akbulut (2012) and extracted with the Baermann funnel technique (Southey 1986). The inoculum density used for each seedling was approximately 1000±100 nematodes of all life stages in 0.5 ml of distilled water.…”

Comparative molecular analysis ofBursaphelenchus vallesianus, a wood‐inhabiting nematode isolated from declining pine trees in theCzechRepublic

“…In contrast, involvement of a few other Bursaphelenchus species, for example B. mucronatus and B. sexdentati, in PWD development remains unclear. However, recent controlled experimental inoculations in greenhouse conditions showed that these species also possess a pathogenic potential (Polomski & Rigling, 2010;Dayi & Akbulut, 2012). Therefore, because of the detection of B. xylophilus in Europe, strategic programmes have been applied to monitor the distribution of Bursaphelenchus spp.…”

“…However, recent bioassays showed that experimental inoculation of 3-yearold P. sylvestris trees led to similar, if not identical, external and internal symptoms that are caused by B. xylophilus (Polomski & Rigling, 2010). More recently, a pathogenic potential of B. vallesianus was also observed in greenhouse conditions, where 2-year-old seedlings of three different pine species, Pinus nigra, P. brutia and P. pinea, were experimentally inoculated (Dayi & Akbulut, 2012). These findings supported the theory that overall mechanisms causing PWD are shared by all pathogenic Bursaphelenchus species, including B. vallesianus (Polomski & Rigling, 2010).…”