Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Relationship between beech bark wounds and bark necrosis and possible methods to control bark necrosis.

Abstract

Beech bark necrosis is considered to be initiated by Nectria spp. and the beech scale insect (Cryptococcus fagi [Cryptococcus fagisuga]). Fifteen fungal isolates were made from necrotic lesions on beech [Fagus sylvatica] trees in Slovakia, and tested for bark infectivity under laboratory and field conditions. The more aggressive fungal isolates caused necrosis of beech bark if it was infected through wounds on both short logs under laboratory conditions, and in living trees under field conditions. These isolates also showed limited budding in the vicinity of the necrosis. The less aggressive isolates brought about necrosis of beech bark infected through wounds only on short logs under laboratory conditions. None of the isolates caused bark necrosis of living beech trees under field conditions unless the bark was wounded. There were no macroscopic symptoms of interactions between the antagonistic fungus Trichoderma harzianum and particular isolates in double cultures. The biopreparation Polyversum (which has Pythium oligandrum as an active ingredient) and the repellent Pellacol (which has thiram 100 g/kg as an active ingredient) inhibited production of undetermined fungal fruiting bodies on necrotic lesions. The biopreparation Supresivit (which has Trichoderma harzianum as an active ingredient) and the fungicide Dithane M 45 (active ingredient 80% mancozeb) as well as Polyversum and Pellacal showed no influence upon the spreading of necrotic lesions.