Occurrence of Bursaphelenchus species in declining Pinus sylvestris in a dry Alpine valley in Switzerland

Abstract

We determined the incidence of Bursaphelenchus species in declining Pinus sylvestris stands in the Swiss Alps. A total of 217 trees showing different degree of decline were sampled from various locations in Valais between 2001 and 2004. Bursaphelenchus species were only found in recently dead or dying trees with an overall incidence of 40%. There was a positive relationship between Bursaphelenchus infestation and blue stain in these trees. Five Bursaphelenchus species were identified: Bursaphelenchus vallesianus, Bursaphelenchus mucronatus, Bursaphelenchus sexdentati, Bursaphelenchus leoni and Bursaphelenchus silvestris. The most frequent species were B. vallesianus detected in 75% and B. mucronatus in 20% of all Bursaphelenchus-positive trees. Bursaphelenchus vallesianus is a recently described species within the B. sexdentati group, and could be a contributing factor in the observed pine decline in Valais.

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

“…4), as expected. Thus, the sequence characterization results provide new evidence about genetic variation distinguishing the Czech isolate of B. vallesianus from other previously described isolates in Switzerland (Polomski et al, 2006) and China (Gu et al, 2006).…”

“…The first occurrence of B. vallesianus was reported in Valais (Switzerland), where this species was isolated from declining Pinus sylvestris trees (Braasch et al, 2004;Polomski et al, 2006). Bursaphelenchus vallesianus is morphologically similar to B. sexdentati and B. borealis, and therefore clearly belongs to the so-called B. sexdentati group (Braasch et al, 2004).…”

Occurrence of Bursaphelenchus mucronatus (Nematoda; Aphelenchoididae) in France and association with Monochamus galloprovincialis (Coleoptera: Cerambycidae)

“…The nematode was found on three pine species: P. nigra, P. pinaster and P. sylvestris. It has already been identified in these species in other European countries [29,33]: in P. nigra and P. sylvestris in Austria and Spain, in P. pinaster in Portugal and Italy and in P. sylvestris in Norway, Sweden, Finland, Poland, Germany and Switzerland.…”

Further observations on sudden diebacks of Scots pine in the European Alps

“…Three chip samples per tree, approximately 1.5 ϫ 1.5 ϫ 1.5 cm (one from the upper, one from the middle and one from the lower part of stem), were cut from the sapwood and stored at 4°C before nematode extraction as described by Polomski et al (2006).…”