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Necrotic spots induced by simulated acid rain on needles of Abies balsamea saplings
Author(s) -
Whitney R. D.,
Ip D. W.
Publication year - 1991
Publication title -
european journal of forest pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.535
H-Index - 49
eISSN - 1439-0329
pISSN - 0300-1237
DOI - 10.1111/j.1439-0329.1991.tb00300.x
Subject(s) - spots , abies balsamea , horticulture , acid rain , precipitation , balsam , shoot , chemistry , botany , biology , ecology , meteorology , physics
Simulated acid rain (SAR) of pH 2.6, 3.6 and 5.6 (control) was applied to Abies balsamea (L.) Mill. saplings at 2‐week intervals for 3 years. Ambient precipitation was excluded from the trees during this period. Light to dark brown necrotic spots along the midribs of needles, 0.1 to 0.5mm in diameter and sometimes having a white center, were associated with the most acidic (pH 2.6) SAR treatment. These spots appeared over a significantly (p = 0.05) larger area of the foliage in the pH 2.6 treatment than in controls (pH 5.6). Needles that received SAR of pH 3.6 had intermediate numbers of spots. The spots persisted for at least 1 2 / 3 years after cessation of SAR application. Needle retention, needle lengths, and the occurrence of epicormic shoots and the needle rust caused by Uredinopsis longimucronata Faull were not significantly (p = 0.05) affected by the SAR treatments. Needle retention tended to be lessened by the most acidic (pH 2.6) SAR treatment. The occurrence of Lophodermium piceae (Fuckel) Höhnel needle cast was significantly lower in the middle tree sections of the pH 5.6 and 3.6 treatments than in the pH 2.6, drought and ambient treatments. Damage by naturally occurring insects was negligible, and was not related to the SAR treatments.