Frost Damage on Canaan Fir Mimics Balsam Twig Aphid Damage

Transcription

Frost Damage on Canaan Fir Mimics Balsam Twig Aphid Damage
Frost Damage on Canaan Fir Mimics Balsam Twig Aphid
Damage
Hort Shorts
Authors
Joe Boggs
Published on
May 27, 2016
I have a prized Canaan fir (Abies balsamea var phanerolepis) in my backyard. It's prized
because I'm a native West Virginian and so is the tree. My wife knows that if we ever move, the
tree is coming with us! The common name of this balsam fir variety is based on its first
discovery in the once isolated, high-mountain Canaan Valley in northeastern WV. Jim Brown
(another native West Virginian and Professor Emeritus, OSU School of Environment and
Natural Resources) spent much of his long career sorting out the five natural seed sources
(provenances) of this tree. The provenances are all found in West Virginia which is why Jim
and other WV natives like to use the alternative common name of West Virginia fir, or West
Virginia balsam fir.
Canaan Fir in the Boggscape
Much of Jim's research focused on making selections that could be economically grown by Ohio
Christmas tree growers to compete with Frasier firs (A. fraseri) grown in other states. However,
freeze/frost damage to new growth was an initial problem encountered with the original Canaan
provenance owing to its early bud break in Ohio. Thankfully, Jim found that selections made out
of other provenances reduced the problem; trees didn't produce new growth until later in the
spring. My tree is one of the later selections and has indeed escaped frost damage each year
… until this year.
On May 16, Greater Cincinnati experienced a record low temperature of 31 F. My Canaan fir
was pushing new growth. At first, it appeared that my lovely (and loved) fir escaped damage,
but as the new growth continued to elongate, curled and deformed new needles began to
appear. The damage was mostly confined to one side of the tree and frankly, it was not very
significant; much of the new growth remains unaffected. However, I was amazed at how much
the damage mimicked symptoms produced by balsam twig aphids (Mindarusspp.). Indeed, I
have made a number of close inspections fully expecting to find the blue-green aphid nymphs
sucking juices at the base of deformed new needles; thus far, no aphids. After eliminating all
other possibilities, I can only conclude that the twisted, deformed needles are the work of Jack
Frost rather than Jane (stem mother) aphid.
Tags
Fir
Canaan Fir
Frost
frost damage