Calico scale, Eulecanium cerasorum, is a pest of variety of woody plants.  Introduced into the San Francisco area in the early 1900’s, it has continued to spread throughout the Pacific Coast states and several eastern states, including Pennsylvania, Maryland, Delaware, Virginia, and Long Island. 

Calico scale’s produce large amounts of honeydew in the spring which can coat tree leaves, branches, sidewalks, and cars.  This sticky sap soon turns black from sooty mold fungi growing on it and in severe cases may interfere with the trees ability to photosynthesize, making it more susceptible to woodborers, drought, and other stresses.

Susceptible Hosts
Calico scale can be a pest to all stone fruit and ornamental fruit trees, elm, maple, zelkova, honeylocust,, sweetgum, magnolia, pyracantha, dogwood, buckeye, boston ivy, and tuliptree,

Pest
Eulecanium cerasorum 

Symptoms
* Large amounts of honeydew in the spring
* Sooty mold fungi growing on the honeydew
* Stunted, yellowing leaves leading to premature leaf drop and dieback

Signs
* Large dark brown and white globular scale about ¼’ in diameter on twigs and branches in May and June 
* Presence of white crawlers on the underside of leaves during summer

Life Cycle
* In late winter to early spring the crawlers molt to the third instar.
* The nymphs move to the leaves to feed along the leaf veins before maturing to adults.
* In mid spring, the females continue to feed, producing eggs beneath them, and eventually turn brown and crusty.
* After egg hatch occurs in late spring, crawlers move to the leaves and settle to feed for the summer months.
* By late summer, the crawlers move back to the woody tissue where they molt to the second instar, which is black and has a harder waxy coating.
* One generation per year.

Distinguishing from Look Alikes
Calico scale at maturity is the only large dark brown and white globular scale about ¼” in diameter for positive field identification. 

Xytect and Transtect are soil applications.
Pure Spray and Bisect are foliar applications.
Xytect can be applied as a foliar application when immediate activity is needed vs. crawlers.

Expectations:
Xytect and Safari will provide a high level of control of all soft scales.  The only reason arborists should apply foliar sprays is for immediate activity vs. crawlers.  Properly timed applications of Xytect or Safari will work extremely well for most soft scales.

Other Treatment Practices:
Promote health and vigor with proper irrigation, mulching, proper pruning and prescription based fertilization practices.

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