Elm Scale

Identification

Size: Elm scale insects are relatively small, typically ranging in size from 1/8 to 1/4 inch (3 to 6 millimeters) in diameter.

Color: Elm scale insects are generally brown or reddish-brown.

Description: Scale insects are a common pest found on backyard trees, ornamental shrubs, greenhouse plants, and houseplants. There are over 1,000 species of scale insects in North America. These pests are oddly shaped and immobile, often resembling shell-like bumps rather than insects. Heavy infestations can build up unnoticed before plants show any damage, resulting in poor growth and yellowed leaves. If left unchecked, an infested host may become so weak that it dies. Adult females lay eggs underneath their protective covering, which hatch over a period of one to three weeks. The newly hatched nymphs, called crawlers, migrate from this covering and move about the plant until they find a suitable feeding site. Young nymphs insert their piercing mouthparts into the plant and begin to feed, gradually developing their own armor as they transform into immobile adults. They do not pupate and may have several overlapping generations per year, especially in greenhouses.

Elm scale insects lay eggs beneath their protective covering, which hatch over a period of one to three weeks. The newly hatched nymphs, or “crawlers,” move to find a suitable feeding site and then insert their piercing mouthparts into the plant to feed.

To manage elm scale infestations, it is essential to monitor trees regularly for signs of infestation and employ appropriate cultural, biological, or chemical control methods as needed. One effective approach is to introduce natural enemies like parasitic wasps or lady beetles, which can help control elm scale populations. Horticultural oils and insecticides may also be used as part of an integrated pest management approach when necessary.

If left untreated, elm scale infestations can lead to significant damage to the host plant, including yellowing and wilting of leaves, reduced tree vigor, and even death. Therefore, it is crucial to address any signs of infestation promptly to ensure the health and vitality of your trees and shrubs.

To identify elm scale, you can look for the following signs:

Bumps or lumps on the bark or leaves of elm trees or other host plants.
A protective waxy coating that covers the scale insect’s body, giving it a round, convex shape.
Sticky honeydew excreted by the scale insect, which can lead to the growth of sooty mold on leaves and branches.
Yellowing or wilting of leaves on the host plant, reduced tree vigor, and even death if left untreated.

If you suspect an elm scale infestation, it is best to contact us at Birch Fumigators to assess the situation and determine the appropriate course of action. Early detection and management can help prevent significant damage to the host plant and ensure its long-term health and vitality.

One of the most obvious signs of an elm scale infestation is the presence of bumps or lumps on the bark or leaves of elm trees or other host plants. These bumps or lumps are the scale insects themselves, which have a round, convex shape and are covered with a waxy protective coating. The color of elm scale can vary from brown to reddish-brown, depending on the species.

Another sign of an elm scale infestation is the presence of sticky honeydew substance on leaves and branches. Honeydew is a sweet, sticky liquid excreted by the scale insects as they feed on the sap of the host plant. This substance can attract other insects like ants and bees and can lead to the growth of sooty mold, a black fungal growth that can cover the leaves and branches of the host plant.

Yellowing or wilting of leaves on the host plant is another sign of an elm scale infestation. As the scale insects feed on the sap of the plant, they can cause damage to the leaves and stems, leading to a reduction in the plant’s ability to photosynthesize and produce energy.

Elm scale is a challenging pest to prevent, and complete prevention is not always possible. Regular monitoring and maintenance of the elm tree are essential for the early detection and control of elm scale infestations.