Page 25 - Free State Summer 2022

are in full bloom. For example, if Chinese lilac, Syringa They have three generations per year and may go
chinensis, is in full bloom at the time the crawler stage of unnoticed until the end of the season when the bright
the scale is present, you can focus on that plant material white male’s covers are very noticeable. The first
as you scout the neighborhood. generation begins in the spring, usually May, followed
Prunicola scale by a mid-summer generation and then again late in the
season. By the end of the season, the population builds
Prunicola scale is found mainly on plants in the Peach to such a high level that they cover the stems and twig-
family, the genus Prunus. In Maryland, Cherry Laurel is a dieback becomes obvious.
common landscape plant susceptible to the prunicola
scale, but it is also found on cherry trees, rhododendrons, Lecanium scale
and boxwoods. We have detected increasing populations Lecanium scale is a soft scale that overwinters in its
showing up in Maryland landscapes. The female scale second instar stage of development. Soft scale insects
has a round cover compared to the bright, white retain their legs during all life stages, so they are capable
elongated cover of the male. of moving if needed but usually are not mobile after
initially settling in the 1st instar stage. As the leaves begin
The crawlers are bright yellow with the typical six legs
common to all insects, antennae and the ability to move to drop, the insects move down toward the stems or trunk
around. Crawlers do not have wings and therefore don’t until the following spring.
fly. Only the males will develop wings; the females never The East Coast has seen a huge rise in lecanium
fly. Crawlers are small and lightweight; a certain number scale populations. Honeylocust and red maples were
will settle close to where they emerged, on the same plant. hit particularly hard in the Richmond, Virginia, area.
Other crawlers are a bit like hitchhikers, they catch a ride Lecanium scale is a soft scale that feeds on the growing
on bird’s feet or larger insects. tips of plants. To obtain a particular protein, these insects
need to take in a large quantity of plant sap and water. In
the process, large amounts of sugar also enter the insect.
The insects excrete this sugar in what is called honeydew,
a sticky sap that covers anything underneath the plant.
Increasing numbers of Lecanium scales were found
in urban areas with more buildings cars and higher
temperatures than were found on wooded sites. Further
study indicated that the higher temperature caused
the scales to appear earlier in the season, before the
parasitoids reached their peak population, so fewer
natural predators were available to suppress the scale
population.

Indian wax scale
Indian wax scale is an introduced species of scale from
India. It was shipped here and became established on
approximately 122 different species of landscape plants.
They are commonly found on holly, pyracantha and
hemlock; and in Baltimore County they’ve been found on
Japanese maple.
This insect looks like a blob of white wax was stuck onto a
plant. It often goes unnoticed until the foliage drops. Once
the foliage on deciduous plants is gone, the stem is visible
Native spicebush with Japanese maple scale and this is when the white bodies of the scale are visible
Photo: Lynette Scaffidi
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