Scale Insects Are a Real Nuisance!

Joe Boggs, The Ohio State University Extension

Honeydew produced by soft scales. (Joe Boggs, The Ohio State University Extension)

During these summer months, there are lots of things in the yard that demand your attention.  In addition to regular mowing, you may be busy with trimming, weeding, planting, mulching, and other assorted tasks.  But even while you are keeping everything looking nice, there may be a problem that is forming on your trees and shrubs without you even noticing.  Scale insects are so small that you may not notice their presence on a tree until they begin doing some real damage.

What Are Scale Insects?

Scale insects are a class of insects named for the protective scales that cover their bodies.  They are typical very small (up to 1/8 of an inch) and without any legs, they move quite slowly if at all.  Scale insects usually survive by finding a good spot along the veins of a leaf and sucking the sap from the leaf.  As long as the leaf continues to provide an adequate supply of sap, they will happily set up camp and stay.

How Do Scale Insects Harm Trees?

While this sounds like a nice arrangement for the scale insect, it doesn’t really work out so well for the tree or shrub.  A healthy tree produces a lot of sap and one scale insect probably wouldn’t do much damage.  However, like many pests, these insects reproduce rapidly and each new generation will find a comfy spot, usually on the same tree, and start sucking away.  The euonymus variety of scale insects can produce up to 3 generations each year!  A constant drain of sap will eventually take its toll on the tree or shrub.

What Other Adverse Effects Do Scale Insects Have?

In addition to putting stress on your trees, scale insects also make a mess in and under your trees.  As they are gorging themselves on sap, these little creatures are also excreting a sticky substance all over the leaves on which they live.  This substance, romantically known as honeydew, covers tree leaves as well as dropping onto the ground or anything else parked under the tree.  (The picture at the top right shows a leaf with honeydew.)  If left undisturbed, honeydew will often lead to the formation of a black sooty mold.

How Can Scale Insects Be Eliminated?

I’m sure you can see why no homeowner with a sound mind would want scale insects.   So what can you do to eliminate these tiny pests?  Due to the protective scale which covers these insects, they are often resistant to normal sprayed insecticides. Full-strength oil sprays may be applied directly to the tree’s leaves during dormant periods in an effort suffocate over-wintering egg masses. However, the timing of application is crucial to safe and effective elimination.  Oil sprays are usually applied in late winter or early spring and should not be applied to trees or shrubs that are fully leafed out.   The most effective and reliable method for getting rid of these pests is the use of systemic insecticides.

If you find that you have scale insects invading a tree, Ping’s Tree Service has the experience and expertise to take care of your problem.  With the mild winter we had this year, we have been seeing more of these sneaky little critters than usual.  But they are no match for our certified arborists.  Scales are not easy to displace once they have taken up residence, but Ping’s will do what it takes to send them packing.  Give us a call to schedule an appointment for a free consultation (317-298-8482).