Page 21 - Free State Summer 2022

TOTAL PLANT MANAGEMENT A Stanton Gill

Armored and Soft Scale

Plaguing Nurseries in 2022

here has been a definite uptick in scale insect development, possessing one pair of wings, as opposed
damage on nursery plants over the last 5 years. to the usual two paired wings on most other insects. The
TWith the demand for nursery plants being strong, other species of insect with just one pair of wings is insects
many scale insects are being passed through into the in the order Diptera. Flies and mosquitoes are in this
landscape. This is not good for the horticulture industry. Diptera order.
Scales, as a group, are one of the most significant Females of most scale species are immobile in the
arthropods that have detrimental impact on an extremely mature stage. The scale shows high degrees of sexual
wide range of trees and shrubs dealt with in tree care as dimorphism. Sexual dimorphism is when the two sexes of
well as in the nursery and landscape industries. There
are over 8,000 described species in 7 families. They were
previously classified in the order Homoptera, but this has
revised so they are now listed in the order Hemiptera,
suborder Sternorrhyncha, and superfamily Coccoidae.
Fortunately for nursery owners, two major families of
scale cause 95% of the plant loss related to scale. The
two families we will discuss in this article are the armored
Scale in the family Diaspididae. The second family is the
soft and wax scales in the family Coccidae. The third
most common of family of scales is Eriococcidae, which is
called the felted scale and includes the now famous crape
myrtle bark scale.

It is often difficult for the untrained eye to detect scale
insects because they don’t look like a typical insect. They
tend to blend into the plant tissue or overwinter in buds.
They are often small, sometimes flattened, raised into
shapes that look like part of the plant, often with various
colors that blend in with the bark or leaves. These factors
result in them often going unnoticed. This ability to blend
is part of their survival mechanism.

Scale Biology
The male and female of the species look quite different.
The males, which are not produced in all scale species, Taxus yew with Pulvinaria floccifera soft scale, commonly called cottony
actually look like insects in the sexual mature stage of Taxus/camellia scale. Look for the scale on the undersides of taxus foliage.
Photo: Bill Stocker
(continued on next page)
Get Active. Stay Involved. • SUMMER 2022 21