TITLE:
The Relationship of the Sapstreak Fungus, Ceratocystis virescens, to Sugar Maple Dieback and Decay in Northern Michigan
AUTHORS:
Tara L. Bal, Dana L. Richter, Andrew J. Storer, Martin F. Jurgensen
KEYWORDS:
Sapstreak Disease; Acer sacharrum; Decay Rates; Crown Dieback
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.2A,
February
28,
2013
ABSTRACT: Unusually high
levels of dieback have recently been reported in sugar maple, Acer saccharum Marsh., in Upper Michigan, and a network of
plots was established to determine the extent and factors associated with the
dieback. A possible contributor to this dieback is sapstreak disease caused by Ceratocystis virescens (Davidson) Moreau. Unhealthy trees with considerable
crown dieback were evaluated across the western Upper Peninsula, MI to
determine the prevalence of the sapstreak fungus using a minimally destructive
sampling technique. Approximately 8% of 90 trees sampled were sapstreak
positive and approximately 10% of trees were positive at one site that had
recently been harvested. While the high levels of maple dieback present in these forests appear not to be
directly caused by widespread sapstreak disease, the occurrence of sapstreak
may be significantly impacting trees at
some locations. However, even when present on a low number of trees, the
biointeraction of sapstreak and decay rates from other fungi could be important
for future tree mortality and value to the forest industry. Therefore, the
effect of two sapstreak fungal isolates on the amount of decay caused by two
common maple white rot fungi, Trametes versicolor (L.:Fr.) Pilat. And Irpex lacteus (Fr.:Fr.) Fr. was tested in the laboratory. Sugar maple
wood blocks were precolonized by two native isolates of C. virescens followed by
inoculation and incubation with decay fungi. Mean percent weight loss of blocks
by white rot decay fungi ranged from 39% to 55%, but decay rates
were not significantly affected by the presence of the sapstreak fungus.