The Effect of Eutypella parasitica on the Wood Decay of Three Maple Species

Ana Brglez,Jožica Gričar,Miha Humar,Nikica Ogris,Barbara Piškur

doi:10.3390/f11060671

Abstract

Eutypella parasitica R.W. Davidson & R.C. Lorenz is the causative agent of Eutypella canker of maple, a destructive disease of maples in Europe and North America. The fungus E. parasitica is known to cause wood stain and decay. However, it is not known how effectively it decomposes the wood of the most widespread maple species in Europe. Wood samples of Acer pseudoplatanus L., A. platanoides L., and A. campestre L. were exposed to four isolates of E. parasitica and nine other fungal species for comparison, according to the modified EN 113 standard. After 15 weeks of incubation, mass loss and microscopical analysis of samples showed evidence of colonization and different wood decay potentials among fungal species. A highly significant positive correlation was found between mass loss and moisture content for all fungal species. Similarly, the measured cell wall thickness correlated well with the calculated mass loss of the samples. On average, the fungal species caused the lowest mass loss in A. pseudoplatanus (10.0%) and the highest in A. campestre (12.6%) samples. Among the samples exposed to E. parasitica isolates, the highest mass loss was recorded in A. pseudoplatanus (6.6%). Statistical analysis showed significant differences in mass loss and moisture content between different E. parasitica isolates. Based on the results of staining, we discuss the type of decay caused by E. parasitica. Although E. parasitica isolates caused smaller mass loss of samples compared to other more effective decay species, we should not disregard its capability of degrading maple wood. Because E. parasitica usually infects the lower portion of the trunk, which is the largest and most valuable part of the tree, any damage can cause significant economic and resource loss.

Highlights

Wood decay is the biological process by which cell wall components are converted to carbon dioxide and water with a release of energy [1,2]
Fifteen weeks of exposure to ten different fungal species resulted in notable mass loss of A. pseudoplatanus, A. platanoides, and A. campestre wood samples
Consistent with Zelinka, Kirker, Bishell, and Glass [38], our results showed that higher amounts of fungal metabolism, which are reflected in higher mass loss, are associated with higher final moisture content

Summary

Introduction

Wood decay is the biological process by which cell wall components (cellulose, hemicellulose, and lignin) are converted to carbon dioxide and water with a release of energy [1,2]. Within a wide spectrum of different types of decay, three main categories are commonly recognized: brown rot, white rot, and soft rot [3]. Different fungi utilize different strategies for degradation and attack the main chemical components of wood [4,5]. When wood-degrading fungi grow through vascular tissues and metabolize wood, a decrease in wood mass and strength usually occurs [2,5]. Loss of wood mass can result in a 70 to 90% loss in wood strength, depending on the wood species. Various host species can be affected differently by the same fungus [6]

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