PHC on the Lookout – Scale 101

Scale insects are a large group of different species that vary in size, color and shape. Host plants include commonly used shade trees, evergreens, shrubs, groundcovers and others. Heavy infestations can seriously debilitate the host plant, possibly killing the plant if infestations continue year after year.

2016 has seen the return of many scale species that were prominent last year.

• Lecanium scale is expected to return with heavy populations this year. Lecanium scale is actually several species of scale that vary in appearance. Hosts include many commonly used shade trees, such as maples, oaks, elms and birch trees. Infested trees usually have sooty mold on the leaves, which is a fungus that grows on the sticky substance (honeydew) excreted by the scale insect.
• Pine needle scale is typically found on mugo and Scotch pines but may also infect other pine varieties. Heavy infestations will turn needles yellowish brown and the pine tree may have a white, snowy appearance. Years of heavy infestations can kill branches and possibly the entire tree.
• Oystershell scale is also commonly found in our area. It’s an armored scale species that prefers ash, maple, dogwood and willow trees, in addition to lilac bushes. The adult scale is found in shades of brown and shaped like an oyster shell.

There are many other species of scale that wreak havoc on landscapes in our area. Euonymus and magnolia scale are a couple other scale species that cause problems for homeowners. Life cycles vary with scale species, making treatment timing critical. For example, magnolia scale typically doesn’t become noticeable to homeowners until late summer when sticky honeydew drips from the plant and sooty mold develops.  Unfortunately, the magnolia scale is protected from chemical treatments at this point and treatment may need to wait until the scale has reached a vulnerable life stage.

Kramer Tree Specialists offers a variety of treatment options to control many scale species commonly found in the area. A certified arborist will properly evaluate the tree to determine treatment recommendations. Call the Plant Health Care Department today!