Magnolia scale, Neolecanium cornuparvum (Thro), is one of the largest scale insects in Pennsylvania. It is native to the United States and is commonly found throughout the eastern part of the country. The magnolia scale removes fluids from the plant using its syringe-like mouthparts and may result in branch dieback or death of the plant if left unchecked.
Saucer Magnolia (Magnolia soulangeana), Cucumbertree Magnolia (Magnolia acuminata) and Lily Magnolia (Magnolia liliiflora). It has also been reported that magnolia scale feeds on Daphne spp., Virginia Creeper (Parthenocissus quinquefolia), and Tuliptree (Liriodendron tulipifera).
The over-wintering nymphs are dark gray-black and cluster together
in large numbers on 1-2 year old branches of the host plant. In the
early summer, the female magnolia scale develops a white waxy coating,
which later disappears in August before newborn crawlers emerge. The
mature female magnolia scale is 1/2" in diameter, smooth, elliptical,
convex and dark brown to pinkish-orange in color. The male scale is
much smaller (about 1/8"), and turns a translucent white color
in early summer before developing into a tiny, pink to yellow gnat-like
insect. Newly hatched crawlers are a medium brown color, getting darker
after feeding commences.
Magnolia scales are usually massed on the undersides of 1 and 2 year
old twigs, with heavy infestations completely encrusting branches.
Other indicators of a scale infestation include reduced foliage and
flower production, undersized leaves and twigs, and a black sooty mold
on the foliage. After digesting the plant fluid, the scale excretes
a clear sticky liquid called honeydew, which provides an ideal substrate
for the black sooty mold fungus to develop. Magnolia scale infestations
often go unnoticed until the leaves and twigs of the host plant turn
black with sooty mold. The honeydew also provides a food source, attracting
ants, bees, wasps and flies.
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Klass C. (1988). Magnolia Scale. Cornell University.
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Shetlar, D. J. (2000). Magnolia Scale And Its Control.
Ohio State University
Townsend, L. (1996). Magnolia Scale. University of