Pine wood nematode
| Pine wood nematode | ||||||||||||
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Males with visible spiculum |
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| Bursaphelenchus xylophilus | ||||||||||||
| (Steiner & Buhrer) Nickle |
The pine wood ( Bursaphelenchus xylophilus ) is a nematode , which in North America ( USA , Canada native) and there pine species attacks. The pine wood nematode does not cause any damage to the conifers found there in its home . Outside of its range, it is now considered one of the most dangerous invasive harmful organisms and is classified as a quarantine pathogen. Infested trees there die within a very short time under optimal conditions for the nematode.
Biology and Symptoms of Damage
The approx. 1 mm long parasitic nematode needs temperatures averaging over 20 ° C in July / August. The pine wood nematode pricks plant cells with its mouth prick to eat. The nematodes penetrate the wood through these injuries and multiply explosively in the water-bearing wood tissue under optimal conditions. This prevents the tree from transporting water . In order to spread, the nematode needs a so-called vector that transfers it from tree to tree. The main vectors are longhorn beetles of the genus Monochamus , which the nematodes transmit when they mature and lay eggs.
Due to an infection with pine wood nematodes, the tree's resin production declines and the needles first turn yellow and then brown, but do not fall off. This creates reddish-brown, unspecific wilting phenomena and the tree eventually dies quickly. The longhorn beetles, which serve as vectors, lay their eggs on weakened trees or on freshly felled, barked wood. There the developing beetles are settled by the nematodes and the maturation feeding transferred to healthy trees of beetles of fresh needles.
Definitive pine nematode infection can only be determined by examining the wood in a laboratory .
Pine species such as Scots pine ( Pinus sylvestris ), black pine ( Pinus nigra ), maritime pine ( Pinus pinaster ), mountain pine ( Pinus mugo ) and Aleppo pine ( Pinus halepensis ) are particularly affected .
distribution
At the beginning of the 20th century, the pine wood nematode came to Japan with round wood deliveries or with packaging wood . The nematode then spread to China , Taiwan , South Korea and Mexico and was first detected in the EU south of Lisbon in Portugal in 1999 on the maritime pine ( Pinus pinaster ). Evidence has been known in Spain and Madeira since then . Presumably, the nematodes also reached the EU in packaging wood with the help of longhorn beetles from Asia; in Portugal and Spain the baker's goat ( Monochamus galloprovincialis ) ensures the spread of the nematodes.
All member states of the EU are obliged to carry out annual surveys on the occurrence of the pine wood nematode.
Risk for Germany, Austria and Switzerland
Under the current climatic conditions, no damage is to be expected in Germany or Austria . In order to develop pathogenic effects, the pine wood nematode needs average temperatures of 20 ° C in July and August. However, even below this temperature it is able to settle in trees and thus cause a latent infestation. Therefore, the nematodes can also develop in Germany. In Switzerland , the pine wood nematode could develop well in the warm inner-alpine valleys of the cantons of Valais and Graubünden . As a result of global warming , it does not seem unrealistic that the pine wood nematode is transported to Central Europe and then also causes damage in Germany.
gallery
B. xylophilus under the microscope
Monochamus alternatus main vector in Japan
M. saltuarius , secondary vector in Japan
M. galloprovincialis , main vector in Europe
Black pine with signs of wilting
Felled, infested black pine
Infested Scots pines
Individual evidence
- ↑ a b C. Tomiczek .: The pine wood nematode - an emergency plan for Austria. In: www.waldwissen.net. September 4, 2014, accessed August 27, 2021 .
- ↑ J. Schumacher, H. Delb: Quarantine harmful organisms in the forest - always new challenges. In: www.waldwissen.net. August 19, 2013, accessed August 28, 2021 .
- ↑ a b S. Prospero, D. Rigling: A threat to Europe's pine forests. In: Wald und Holz 11/16. Retrieved August 27, 2021 .
- ↑ The 11 most important quarantine pests. In: www.waldwissen.net. July 5, 2021, accessed August 27, 2021 .
- ↑ a b Profile of pine wood nematode (Bursaphelenchus xylophilus). In: plant health.julius-kuehn.de. Julius Kühn-Institut, Federal Research Institute for Cultivated Plants (JKI), accessed on August 27, 2021 .
- ↑ T. Schröder: The pine wood nematode. In: www.waldwissen.net. August 31, 2004, accessed August 27, 2021 .
- ↑ The pine wood nematode . LWF, Bavarian State Institute for Forests and Forestry, accessed on September 1, 2021 .