Open AccessSusceptibility of Chinese Hemlock (Tsuga chinensis) to Injury from Autumn Horticultural Oil Applications
Author(s) -
Richard W. Harper,
Richard S. Cowles
Publication year - 2013
Publication title -
arboriculture and urban forestry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.222
H-Index - 47
eISSN - 2155-0778
pISSN - 1935-5297
DOI - 10.48044/jauf.2013.002
Subject(s) - tsuga , biology , western hemlock , spider mite , invasive species , ecology , mite
Chinese hemlock (Tsuga chinensis) has been suggested as a possible replacement in landscape plantings for eastern hemlocks (T. canadensis), which are being lost due to infestations of hemlock woolly adelgid (Adelges tsugae). Chinese hemlock is highly resistant to hemlock woolly adelgid, but is a host for elongate hemlock scale (Fiorinia externa). Horticultural oil is a popular insecticide commonly used by professionals to manage various insect and mite pests of hemlock in landscapes, including hemlock woolly adelgid, spruce spider mite, and armored scales. In tests, horticultural oil applied in two separate autumn sprays was not phytotoxic to Chinese hemlocks. Therefore, 1% or 2% horticultural oil may be used to maintain Chinese hemlocks in landscape plantings.