Magnolia scale: what the extension services record

This page describes what the named sources say. It is not a diagnosis of any tree and does not say what should be done with one. None of the four pages read lists magnolia scale as regulated or notifiable. Each section names its source, all read on October 9, 2026. The scale has a row in insect pests of trees, which compares it with the other scale insects and caterpillars listed there.

Names, origin and range

All four sources give the scientific name Neolecanium cornuparvum. Penn State Extension says the species is native to the United States and widely distributed across the eastern states, and calls it one of the largest scale insects in the country. NC State Extension also calls it one of the largest scale insects, and Ohio State Extension calls it one of the largest and most conspicuous scales known in Ohio. Penn State gives one generation a year in Pennsylvania, and NC State gives one generation a year.

Hosts

Source	Hosts named	Look-alike or caution named
Penn State Extension	Magnolia only.	None named.
NC State Extension	Magnolia and tulip tree, which it says are sometimes quite damaged.	None named.
Ohio State Extension (ENT-61)	Mostly magnolias. Saucer, star and lily magnolias are the ones most often attacked, sometimes heavily; cucumber tree and southern species are occasionally attacked but rarely damaged.	Occasionally confused with the tuliptree scale, another large soft scale that infests tuliptree and magnolia.
University of Vermont Extension	Only magnolias, including star magnolia and saucer magnolia.	Adults can be mistaken for plant buds.

The sources therefore differ on tulip tree: NC State includes it, Penn State and Vermont say magnolia only. Ohio State treats tuliptree scale as a separate insect. The profile for cucumbertree is one of the magnolia relatives on this site.

What the scale looks like

Penn State describes adult females as about 12 mm across, smooth, elliptical, convex and pinkish-orange to brown, covered in white waxy coating, with overwintering nymphs dark gray with a red-brown ridge down the middle. Ohio State says adult females may reach nearly a half inch, are shiny tan-brown and smooth, and carry a white mealy wax that is lost when the crawlers emerge. Vermont gives shiny brown adults up to one-half inch long, and says females turn brown and purple in early to mid-summer with a white wax that disappears in late summer. Ohio State says males stay small, about one-eighth inch, and emerge as gnat-like insects with two long waxy threads from the tip of the abdomen.

Life cycle as the sources state it

All four say the scale overwinters as tiny nymphs on the twigs; Penn State and Ohio State specify one- or two-year-old twigs. Penn State says nymphs mature in late July through early August, males emerge at about the same time as small fly-like insects, mate and die. NC State calls the biology unusual because the scale reproduces in late summer, when most soft scales of ornamentals reproduce in May or early June, and says the eggs hatch as they are laid so the crawlers seem to be born live. Penn State says females give birth to living crawlers in late August or early September, Ohio State says late July and August, and Vermont says late August into September. The crawlers wander briefly and then settle on young twigs to overwinter.

Damage as the sources describe it

Ohio State says the scale removes plant fluid with sucking mouthparts, that heavily infested branches and twigs are weakened and stunted, leaf development may stop and the canopy thins, and that under continuous heavy infestation even mature trees may be killed. NC State describes sparse foliage, dead branches, trunks distorted where the leader branches are killed over the years, and honeydew with black sooty mold. Ohio State calls the sooty mold generally harmless and a nuisance, though it says complete cover of leaves may hinder photosynthesis. Vermont says the mold mainly reduces the sun reaching the leaves, that high populations can cause yellowing, twig dieback and overall decline, and that honeydew attracts wasps and ants. NC State and Ohio State add bees and flies.

Natural enemies and status

Ohio State says several predators and parasites attack the scale but are rarely effective at suppressing populations, especially on smaller magnolias. Vermont says the female dies after producing crawlers but her scale covering may stay on the tree, and Ohio State notes the large old shells often remain from an earlier season. No page names a quarantine or a report line. This page gives no treatment steps, product names, rates or timings. For who may apply pesticides see pesticide licences.