For release: May 25, 2010
Calico Scale --
Insects Causing Sticky Lawns and Sparse Trees
(Troy, MI) –
Residents noticing a strange “sap” dripping from their trees can blame the
situation on the Calico Scale insect infesting many trees in Michigan. While scale doesn’t usually kill trees, it
may weaken them making the trees susceptible to other environmental stresses.
Scale infestations
run in 5-10 year cycles and the parasites and predators necessary to lower the
scale population are slowly growing in number.
Currently, heavy infestations are being reported in Canton and East
Lansing.
Troy did inject
trees for scale in 2007, 2008, and 2009 with little success. Troy’s 2010 management plan for the
infestation is to stop all chemical treatments and encourage natural predators
to bring the scale levels down. In the
meantime, the City will continue to investigate and test alternative
treatments.
The calico scale
is a small pest that measures about a quarter of an inch in diameter and
infects woody landscape plants. Calico
scale can be spread by windblown crawlers or carried on the feet of birds. The first symptom is usually a “honeydew
rain” that glistens on lawns and bushes below infested trees. The honeydew is a sugary liquid waste
excreted by the calico scale.
Plants attacked
include dogwood, redbud, crabapple, honey locust, elm magnolia, maple, sweet
gum, tulip tree, oak, zelkova, pear and many more.
The scale is
believed to have been introduced into the
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