The terrapin scale, Mesolecanium nigrofasciatum (Pergande), is a pest of tree fruits and shrubs in the southern and eastern United States.
Like other scale insects, this species is immobile (sessile) during most of its life cycle and secretes a stiff, hemispherical covering over its body.
This protective coating (called a derm) is brown or reddish-brown and is distinguished by radiating black stripes resembling a turtle’s shell.
The derm expands with the insect, reaching a diameter of 3 to 4 mm (approximately 1/8 inch).
Host plant:
Both scale insects are significant peach pests, but other fruits and shade trees also serve as hosts. P. corni, as well as P. persicae (Fabr.) (brought from Europe) and the cottony maple scale, Neopulvinaria innumerabilis (Rathvon), a North American species, may be a problem on a grape.
Territory:
Terrapin scales and European fruit lecaniums are two insects with a broad range. The terrapin scale is a natural species found in the eastern United States and southern Canada.
Damages causedbyTerrapin Scale:
Since scale insects feed by removing sap from a plant, they can reduce vigor, decrease yield, and even shorten the lifespan of infested bushes. Heavy infestations also produce large quantities of honeydew. This sugary waste product often coats the foliage, fostering the growth of a sooty mold that blocks light and reduces the plant’s photosynthetic efficiency.
Life history and habits:
The terrapin scale has just one generation each year. Mated females overwinter on host plant stems (typically from the previous season’s growth) and give birth to live young in early June, lasting 4 to 6 weeks. The crawlers, or baby scale insects, travel to the leaves, settling along the midrib and veins (typically on the underside) and beginning to secrete a derm. Females return to the stems in late summer for fast growth and sexual development. Males stay on the leaves until they reach sexual maturity, at which point they move to the limbs, mate with the females, and die within a few days. Females continue to feed and grow on the branches until winter weather forces them to hibernate.
