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What Is Elongate Hemlock Scale

What Is Elongate Hemlock Scale

If you live in Massachusetts or New Hampshire, you might have noticed some pests similar to white specks commonly on pine trees. The insects become visible after heavy rains and usually destroy pine trees, making their needles yellow or causing them to fall off prematurely. Well, those are the Elongate Hemlock Scale. Mayer Tree Service can help you identify and control Elongate Hemlock Scale.

But before you can manage these insects, you need to learn how to identify them. This article discusses Elongate Hemlock Scale. We’ll tell you everything you need to know about these insects and help you identify them if you see them on your trees

Elongate Hemlock Scale

Elongate Hemlock Scale in Baltimore Co., Maryland (11/20/2018). Photo by Josh Emm

What Is Elongate Hemlock Scale?

The elongate hemlock scale (Fiorinia externa) is a tree pest that harms hemlocks, spruces, and other trees. The insect is native to Japan.

The elongate hemlock scale has been present in the United States for many years, but it was only recently discovered in Pennsylvania. Today, the insect has spread fast, and you can expect to find it on hemlock trees across the state. The pest has also been found in Washington state and Oregon.

It is a tiny insect growing to a maximum size of 3 millimeters (approximately 0.1 inches). The adult female produces approximately 200 eggs in her lifetime, laying them under her own body during winter. 

The eggs hatch in late spring, specifically May and June, just after the new growth on the tree has emerged. The nymphs move from one twig to another by walking, so they often become concentrated on the lower branches of trees where the foliage is denser. 

Nymphs feed by sucking fluids from individual needles, causing them to turn yellow or reddish-brown and fall off prematurely. By August or September, the nymphs are mature enough to begin producing their eggs for the coming year’s generations. Scale insects can reproduce parthenogenetically. This means that Elongate Hemlock Scale females can produce viable offspring without fertilization from males.

Dealing with the Elongate hemlock scale at this stage is recommended. You can rely on Meyer Tree Service- Essex to manage and control the elongate hemlock scale early while still at the Nymph stage to help protect your trees. At Meyer Tree Service, we have been providing tree care services to clients in the Cleveland area since 2008, and we are ready to help you too!

How to spot elongate hemlock scale

Look for white specks 1/32 inch long (0.8mm), raised above the leaf’s surface. The female insects are wingless and immobile after settling under their protective covering, but they can move around while still young and soft-bodied.

When an adult female elongate hemlock scale lays eggs in early summer, she covers herself with a waxy white coating that forms a white oval structure about 2 mm across with a dark spot at one end. Adult males are tiny winged insects that look like gnats or fruit flies.

Elongate Hemlock Scale

Elongate Hemlock Scale.  Photo by

Signs of infestation

Look for these signs of elongate hemlock scale:

  • White or grayish bumps on branches and trunks (about 2–3 mm long). These bumps are oval-shaped, with one end rounded and the other tapering to a point.
  • Large amounts of honeydew are sticky substances that insects excrete while feeding.
  • Black sooty mold growing on the honeydew.
  • Premature needle drop or a thinning crown.

Where to Find Elongate Hemlock Scale

Elongate hemlock scale (Fiorinia externa) is a sap-feeding insect that attacks and kills hemlock trees. Larvae are “crawlers” (the mobile stage of an insect) and spend most of their lives on the tree’s bark.  They compromise the health of the needles which causes them to drop. This is obviously harmful to any plant but especially hemlocks which store a lot of energy in their foliage. This is a major reason why Elongate Scale weakens and kills trees so quickly.

Adult Elongate scale is mainly found on the interior foliage of evergreen trees and shrubs, but it also lives on the outside of branches.

Elongate Hemlock Scale Life Cycle

EHS has a complex life cycle with two generations per year, overlapping adult stages, and many feeding stages for most of the year. The pest overwinters as eggs beneath the protective armor of females on twigs. Eggs hatch from mid-May to early June into crawlers (immature nymphs). 

Crawlers are tiny, yellowish insects that move to needles or twigs where they settle and begin feeding by inserting their mouthparts into their hands. Their feeding causes long streaks of yellow or white stippling along with needles.

A clear exudate called honeydew is produced by feeding crawlers and can cover leaves and needles below infested branches, making them sticky and shiny. Often black sooty mold grows on this honeydew and accumulates on hands and branches beneath infested parts of trees.

Damage it causes

Damage caused by this scale insect is two-fold. The feeding activity of the scale insect causes needle loss, which leads to a decrease in the vigor of infested trees. Infested trees are more prone to winter injury than non-infested trees. The effect of heavy infestations can be seen easily after a winter season; trees will be almost devoid of needles, except for those on new growth.

Preventing and Controlling Elongate Hemlock Scale

The easiest way to deal with an elongate hemlock scale is to prevent it. Monitor your existing trees, especially your hemlocks.  Before bringing home a new tree, inspect it carefully for signs of the pest. If you find any evidence of an elongate hemlock scale, don’t buy it.

To prevent spread, isolate newly purchased trees away from other conifers until they’ve been inspected and cleared of pests. Keep an eye for insects or diseases and check the trees monthly.

Call Mayer Tree Service Today!

Elongate hemlock scale is becoming a common pest in our area.  It is rare to see hemlocks that does not have elongate scale. It causes hemlock trees to turn brown and deteriorate, resulting in death. However, you can take steps to manage this insect and protect your hemlock trees.

For more information on the Elongate Hemlock Scale and its prevention methods, contact us at Meyers Tree service- Essex or  Mayer Tree Service – Lincoln. We’ll be happy to help!

If you have questions about tree service or plant health care or would like an estimate, give us a call at 978-768-6999 or click here to contact us.

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