Barnacle Scale: Appearance, Territory, Damage, and Life Cycle

Latin Name: Ceroplastes Cirripediformis

Appearance: Barnacle scales are reddish-brown to brown in color; however, they are entirely coated with a thick coating (test) of pearly-gray wax. They are 14 inches long, wax and all. These scale insects resemble barnacles, therefore their common names. The form is thick and uneven. They’re covered in a thick coating of wax, giving them a gleaming white appearance. They have a few black-brown markings around the shell that are about half a millimeter in size. Nymphs are partially or completely coated in a pattern of pure white conical wax plates, which subsequently appear as buttons on mature females. Males are uncommon. Males are not well described; however, they are most likely small, gnat-like adults.

Hosts Plants: Barnacle scales have been found in 119 genera and 63 families of plants, including Cannabis, citrus, gardenia, guava, passion flower, and many more. Gardenia is the most prevalent host in North Carolina. Plants infected with sooty mold can turn practically black, and plant development is slowed.

Territory: Native to temperate areas in the United States, it is currently found from California to Florida.

Damage Insect Cause: Wax scales are a sporadic pest of a variety of ornamentals. Ceroplastes spp. may make a sticky mess on a variety of hosts by excreting excessive amounts of honeydew. Infestations of this kind seldom, if ever, endanger plant health.

Insects with pearly white shells clung to plant branches. The leaves may be yellow if there is a significant infestation. Premature leaf drop. Honeydew is a transparent, sticky material that can be found on leaves and bark. Ants can exacerbate the infestation.

Life History and Habits: Barnacle scale adults can be seen from late July to the end of winter. Early instar nymphs are often found on the top side of leaves. Third instar nymphs develop into females and deposit eggs under their bodies on twigs.

Wax scale from China from May through September, mature females are present. Autumn is the best time for egg hatching. Males do exist, although they are uncommon. Wax scales appear to produce one generation every year. Crawlers are most plentiful in the fall, but they can be found throughout the year.